WO2004091823A1 - Tube with high dimensional accuracy, and method and device for manufacturing the tube - Google Patents

Abstract

A tube with a high dimensional accuracy manufacturable at low cost and having sufficient fatigue strength throughout the wide range of size requirement of the tube and a method of manufacturing the tube. With a plug (1) inserted into a metal tube (5), the metal tube (5) is pushed and passed through the hole of a die (2) for pushing-out. Thus, the pushed-out tube with the high dimensional accuracy in which one or more of an outer diameter deviation, inner diameter deviation, and circumferential wall thickness deviation are 3.0% or less can be provided.

Description

 Description High dimensional precision tube, its manufacturing method and manufacturing equipment

 The present invention relates to a high dimensional accuracy pipe, a method for manufacturing the same, and a manufacturing apparatus. For example, the present invention relates to a high-dimensional precision pipe, a method for manufacturing a high-dimensional precision pipe, a manufacturing equipment, a manufacturing equipment line, and a manufacturing equipment line applicable to components requiring high dimensional accuracy, such as driving system parts for automobiles. Background art

 Metal pipes such as steel pipes are generally classified into welded pipes and seamless pipes. The welded pipe is manufactured by rounding the width of a strip and welding both ends of the rounded width to each other like an electric steel pipe. On the other hand, seamless pipes are manufactured by drilling a solid billet at a high temperature and rolling it with a mandrel mill. In the case of a welded pipe, the bulge of the welded portion is ground after welding to improve the dimensional accuracy of the pipe, but the wall thickness deviation exceeds 3.0%; In addition, in the case of a fibrous tube, eccentricity and eccentricity occur in the perforation step, and a large thickness deviation is likely to occur due to the deviation. Efforts have been made to reduce this thickness deviation in the post-process, but it is still not possible to reduce it sufficiently, and more than 8.0% remains in the product stage.

 Recently, there has been a strong demand for lighter vehicles as a countermeasure against environmental problems. Drive system components such as drive shafts are being replaced by solid metal rods and hollow metal tubes. These metal pipes for driving system components for automobiles require high dimensional accuracy of 3.0% or less, and more strictly 1.0% or less, in thickness, inner diameter, and outer diameter deviations.

 (4) Vehicle components must withstand fatigue caused by long-distance running of the vehicle. If the accuracy of the wall thickness, inner diameter, and outer diameter of the metal pipe is poor, fatigue fracture will inevitably progress from the irregularities existing on the inner and outer surfaces of the pipe, and the fatigue strength will be significantly reduced. In order to maintain sufficient fatigue strength, it is necessary to improve the accuracy of the wall thickness, inner diameter, and outer diameter of the metal tube.

 Hereinafter, the high dimensional accuracy pipe referred to in the present invention is a pipe in which one or more of the outer diameter deviation, the inner diameter deviation, and the circumferential wall thickness deviation are 3% or less, and each deviation is: It is derived by the following equation.

 Deviation-fluctuation range / (target value or average value) X 100%

Fluctuation range-maximum value-minimum value The following two methods are generally known as means for improving the accuracy of the wall thickness, inner diameter, and outer diameter of a metal tube. Hereinafter, a welded steel pipe and a seamless steel pipe (hereinafter referred to as a steel pipe or a pipe) will be described. One is a method of cold drawing a steel pipe using a die and a plug (so-called cold drawing method) (see Patent Document 5). Another method is a method of pressing a steel pipe into a die hole using a rotary forging machine incorporating a die divided in a circumferential direction (rotary forging press-in method) (see Patent Documents 1, 2, and 3).

 Patent Document 1: Japanese Patent Application Laid-Open No. Hei 9-26 26 63 7

 Patent Document 2: JP-A-9-12662619

 Patent Document 3: Japanese Patent Application Laid-Open No. H10-105612

 Patent Document 4: Patent No. 288584446

 Patent Literature 5: Patent No. 2812 21 51

 However, in the cold drawing method, when the equipment capacity is insufficient, or when the wall thickness of the pipe is so large that the pulling stress cannot be obtained and the reduction ratio must be reduced, the machining tool (plug Insufficient contact between the die and the pipe, and between the extraction plug and the pipe within the gap between the die and the inner surface of the die hole). In the cold traction method, the stress of the pipe is the tensile force. In this case, the smoothness of the inner and outer surfaces of the tube is insufficient, and irregularities are likely to remain. As a countermeasure, the diameter of the pipe is reduced by cold pulling to improve the contact between the inner and outer surfaces of the pipe, the plug, and the die in the machined pile. However, when the pipe is cold-drawn using a die, the larger the diameter reduction rate of the pipe, the greater the roughness due to the convexity of the inner surface of the pipe. As a result, it is difficult to obtain tubes with high dimensional accuracy by the cold drawing method. For this reason, the fatigue strength of the pipe was not sufficient, and a pipe with better dimensional accuracy was strongly demanded. In the cold traction method, the tip of the pipe must be narrowed because the tip of the pipe is sandwiched to apply tension. As a result, they had to be pulled out one by one, resulting in a problem of extremely low processing efficiency. Also, even if the facility has the capacity to increase the diameter reduction rate, the processing distortion due to the diameter reduction is increased, and the pipe is liable to work hardening. After drawing, the pipe is further processed such as bending and smoothing. Due to the work hardening in the drawing, there is a problem that cracks are likely to occur in a subsequent bending step or the like. In order to prevent this, it is necessary to perform heat treatment at a high temperature for a sufficient amount of time after drawing, which significantly increases the manufacturing cost. There was an eager way to do it.

The metal tube pressing device described in Patent Document 4 pulls the metal tube with another device, prevents the tube from breaking due to the pulling, and reduces the tensile force required to form a groove on the inner surface. It does not smooth the inside and outside of the tube.

 In the rotary forging indentation method described in Patent Documents 1 to 3, as a result of dividing the dies of the rotary forging machine and swinging the dies, a step is easily generated in the divided portion, and the outer surface is insufficiently smoothed, Alternatively, uneven stiffness of the dies in the circumferential direction may cause uneven deformation. As a result, the wall thickness accuracy was insufficient, and the target finish dimensional accuracy could not be obtained sufficiently. The fatigue strength of the steel pipe was not sufficient, and improvement was required.

 In the rotary forging indentation method, the wall thickness after pushing in the steel pipe is thicker than the wall thickness before pushing in. This is a limitation due to the use of a rotary forging machine, which has a complicated structure and is difficult to apply a load. In order to increase the wall thickness, the gap is increased closer to the outlet in the machining tool to make the tube easier to deform. Live. If the wall thickness is further increased, the gap will increase, and the tube will not sufficiently adhere to the die surface or plug surface. As a result, there was a drawback in that it was difficult to obtain a high-dimensional precision pipe without smoothing of the pipe surface.

 Also, when manufacturing high dimensional precision pipes, if the frictional force between the plug outer surface and the tube inner surface and between the die inner surface and the tube outer surface is not reduced as much as possible, flaws such as seizure may occur on the pipe surface during processing. However, the surface quality of the pipe after processing deteriorates, and the pipe does not become a product, but force = », and the load at the time of processing is delicate and the processing itself may not be possible, and as a result, the production efficiency may be reduced. It had dropped significantly.

 As a result, in order to obtain a desired thickness after pressing, the thickness before pressing must be reduced. Therefore, in order to prepare pipes of various product sizes and to improve the performance such as the fatigue strength of those pipes, it is necessary to prepare many pipe sizes. However, there are restrictions on the raw pipe manufacturing equipment and many sizes cannot be prepared, so the total required size of pipes! : It was difficult to obtain good dimensions. Also, in the case of automotive parts, the degree of processing of the pipe is changed and used. For example, for some parts, it is considered to reduce the degree of work and omit the heat treatment after processing. For other parts, the degree of work is significantly increased and the strength is increased.

However, in the conventional cold-pulling method and rotary forging indentation method, only the diameter reduction is performed, and the outer diameter of the tube after processing is uniquely determined by the die die, and the wall thickness is also uniquely determined by the die and plug. Therefore, it was almost impossible to produce pipes of the same size with different degrees of processing from the same raw pipe, since only a unique degree of processing could be obtained from the same raw pipe. Therefore, in order to manufacture tubes with the same size but different degrees of processing, prepare multiple sizes of raw tubes and change the diameter reduction ratio. And it took a lot of time and effort to manufacture the pipes.

 As described above, it is difficult to obtain high-precision pipes with conventional technology, and when manufacturing pipes of the same size but different degrees of processing, it is necessary to prepare a large number of Hata pipes of different sizes. There was a problem that was not.

 The present inventors have studied a processing method capable of producing a pipe with higher dimensional accuracy than drawing in order to solve the above problem, and have concluded that punching is a promising weather trap. In the case of punching, as shown in Fig. 10, the plug 1 is inserted into the pipe 4, and the pipe 4 is pushed into the die 2 by the pipe pusher 3 while the plug 1 is floating, so that all the compressive stresses are formed in the machined pile. Works. As a result, the tube has sufficient contact with the plug and the die, regardless of the entry and exit sides of the processing byte. Moreover, even with a small diameter reduction ratio, the inside of the machined tool is in a compressive stress state, so that the pipe and the plug and the pipe and the die are more easily in contact with each other than withdrawal, and the pipe is smooth and smooth. The result is a tube with high dimensional accuracy.

 However, when performing the punching process, the plug was stuck in the tube and the load increased, and as a result, the raw tube to be pushed buckled and processing could not be performed. Causes include insufficient amount of lubricant applied, changes in the surface properties of the tube, deformation of plugs and dies due to frictional heat and heat generated during punching, etc. In order to continue punching, it must first be judged on the spot during machining whether or not machining is possible.

 Conventionally, the operator makes intuitive judgments based on the vibration noise of the pipe pusher or the displacement of the hydraulic meter, or the processing is forcibly performed, the die is broken, the processing is stopped, the punching conditions are reviewed, and the processing is performed again. Was. In other words, the conditions were changed even in a state in which processing was possible, which was considerably looser than the punching processing limit, or the conditions were changed only after the die became cracked due to an extremely severe processing state. As a result, wasteful machining time was required, or the time required to change the dies was extremely long, resulting in low productivity.

In conventional drawing, in order to improve the dimensional accuracy of the pipe, it was necessary to bond the pipe before drawing and then apply a metal stone to form a sufficient lubricating film. Therefore, it is necessary to take sufficient time to form a lubricating film, and pretreatment of the pipe such as pickling is also necessary. Multiple tanks were required. Also, in order to perform the drawing process, it was necessary to apply a knurling process to the pipe end using a rotary forging machine or the like. However, if these equipment rows are placed online and arranged on the inlet side of the drawing equipment, productivity will be reduced and a serious problem will occur, so lubrication will be performed in a separate process. Then, the pipes were put into a line of drawn online equipment for processing.

 In other words, it was difficult to increase the production efficiency of the conventional high-dimensional-precision pipe manufacturing equipment line because of the premise of drawing, which requires a long pretreatment step.

 As described above, with the conventional cold-pulling method and rotary-forging indentation method, it is difficult to obtain a pipe with high dimensional accuracy, and the problem that the surface quality of the pipe may be reduced remains unsolved. Was. In view of the problems with the prior art described above, the present invention provides a wide range of required tube sizes! The objective of the present invention is to provide a dimensional accuracy pipe which can be manufactured at low cost and has sufficient fatigue strength, a method of manufacturing the same, and a production equipment line for producing it with high efficiency. Disclosure of the invention

 The present invention that has achieved the above object is as follows.

 1. The metal pipe is pushed into the hole of the die with a plug inserted in the pipe and passed through. Any of the outer diameter deviation, inner diameter deviation, and circumferential wall thickness deviation manufactured by performing punching. High-precision as-extruded tubes characterized in that at least two of them are not more than 3.0%.

 2. Push the metal tube into the hole of the die with the plug inserted into the tube and pass it through. The metal tube on the exit side of the die is made thinner than that on the entry side. Wherein one or more of the outer diameter deviation, the inner diameter deviation, and the circumferential thickness deviation are not more than 3.0%. .

 3. The high dimensional precision tube according to 1 or 2, wherein the punching is performed while the metal tube is circumscribed entirely around the plug and entirely around the die within the same cross section of the tube.

 4. The small dimensional accuracy tube according to any one of 1. to 3., wherein the die is an integrated die or a fixed die.

 5. A method for manufacturing a dimensional precision tube, wherein a metal tube is pushed into a die with a plug inserted into the tube and passed therethrough.

 6. The method for manufacturing a high-precision pipe described in 5 above, wherein the thickness of the pipe on the outlet side of the die is equal to or less than the thickness of the pipe on the inlet side.

7. The high dimension according to 5. or 6., wherein the punching is performed while the metal pipe is circumscribed entirely around the plug and the die entirely around the same cutting plane of the pipe. Accuracy Pipe manufacturing method. 8. The method for producing a high dimensional precision tube according to any one of 5 to 7, wherein the die is an integrated die, a Z die or a fixed die.

 9. The method of manufacturing a high-precision pipe according to any one of 5. to 8., wherein the plug is a floating plug.

 10. In step 5, in order to improve one or more of the outer diameter deviation, inner diameter deviation, and circumferential wall thickness deviation of the pipe by punching to obtain a high dimensional accuracy pipe, insert a plug into the pipe. A high-efficiency production method for high-dimensional precision pipes, wherein pipes are continuously fed into a die by means of a pipe feeding means on the die entry side while being charged and floated.

 11. The method according to claim 10, wherein the pipe feeding means is a snapper for gripping a pipe before processing. ·

 12. The method according to claim 10, wherein the pipe feeding means is an endless belt for holding the pipe before processing.

 13. The method according to the above-mentioned item 10, wherein the pipe feeding means is an intermittent feeder for alternately intermittently feeding a pipe before processing.

 14. The high-efficiency manufacturing method for a high-dimensional precision pipe according to 10., wherein the pipe feeding means is a press for sequentially pressing the pipe before processing.

 15. The high-efficiency manufacturing method for a high-dimensional precision pipe according to 10., wherein the pipe feeding means is a hole-type roll for holding the pipe before processing.

 16. The high-efficiency method for producing a high-dimensional precision pipe according to 15, wherein the grooved roll is a roll having two or more rolls.

 17. The high-efficiency manufacturing method for a high-precision pipe according to claim 15 or 16, wherein two or more stands of the grooved roll are installed.

 18. In 5., after forming a lubricating coating on the inner and / or outer surface of the tube, insert a plug into the tube, and punch out the tube with a die to obtain high dimensions with good surface quality. Manufacturing method for precision tubes.

 19. The method for producing a high dimensional accuracy tube with a good surface quality on the IE as described above, wherein the tube on which the lubricating film is formed is a steel tube on which oxide scale remains adhered.

 20. The method for producing a high-dimensional precision tube having good surface quality according to item 18 or 19, wherein the lubricating film is formed using a liquid lubricant.

21. The lubricating film is formed using a grease-based lubricant. Or the method for producing a high-precision pipe having good surface quality described in 1 9.

 22. The method for producing a high-dimensional precision tube having a good surface quality according to 1 to 8 or 19, wherein the lubricating film is formed using a drying resin.

 23. After applying the drying resin, a liquid obtained by diluting the drying resin with a solvent, or an emulsion of the drying resin to a tube, exposing the tube to hot air or air drying to form the lubricating film. 23. The method for producing a high dimensional accuracy tube having good surface quality according to item 22, wherein

 24. In 5., this is a method for manufacturing high-precision pipes that manufactures pipes of the same size with different processing degrees from pipes of the same size with high dimensional accuracy. A method for producing high-dimensional precision pipes, which is characterized in that the pipes are charged into a die and the pipes are punched out with a die. '

 25. The method for manufacturing a highly dimensionally accurate tube according to the above item 24, wherein the plug is floated in the tube, and the tube is supplied to the die in a continuous gun.

 26. The method of manufacturing a high-precision pipe according to 24 or 25, wherein the plug is a plug in which a tapered angle of an expanded portion is smaller than a tapered angle of a reduced-diameter portion.

 27. The method for manufacturing a high-precision pipe according to any one of 24 to 26, wherein the target outer diameter of the pipe on the outlet side of the die is smaller than the outer diameter of the pipe on the inlet side.

 28. In 5., at the time of manufacturing a high dimensional accuracy pipe by punching a pipe in which a plug is inserted into the hole of the die and passing it through, the angle between the surface of the reduced diameter portion and the processing center axis as the plug Using a plug with a diameter of 5 to 40 ° and a length of the reduced diameter portion of 5 to 10 Omm, and using a die with an angle of 5 to 40 ° between the inner surface of the hole on the inlet side and the processing center axis as the die A stable production method for a high-dimensional precision pipe.

 29. The method for producing a high-precision pipe according to the above description, characterized in that the length of the bearing portion of the plug is 5 to 20 Omm.

 30. The method for stably manufacturing a high-dimensional precision pipe described in 28. or 29., characterized in that the pipe thickness at the outlet side of the die is set to be equal to or less than the pipe thickness at the inlet side. .

 3 1. The method for producing a highly dimensionally accurate pipe according to any one of the items 28 to 30, wherein an integrated fixed die is used as the die.

32. The method for stably manufacturing a high-dimensional precision pipe according to any one of 28 to 31, wherein the plug is floated in the pipe. 33. In 5., while inserting the plug into the pipe and floating it, press the pipe into the die and perform punching. In the method of manufacturing dimensional precision pipes, during the punching process, Is measured, and the measured load is compared with the calculated load calculated from any of the following [Equation 1] to [Equation 3] from the material properties of the untreated tube, and based on the result. A stable manufacturing method for high-dimensional precision pipes, characterized by determining whether or not continuation of press working is possible.

 Record

[Formula 1] _{ff k} X cross section

here, . _k = YS X (1-a X λ), λ = (L / Vn) / k, a = 0.0001 85 to 0.015 5, L: length of pipe, k: secondary radius of section, Ι ^-+ ά ΙΙ / Ι Θ, n: Tube end condition (n = 0.25 to 4), d! : Outer diameter of Hata pipe, d ₂ : Inner diameter of pipe, YS: Yield strength of pipe

(Equation 2) Yield strength of pipe YS X Cross section of pipe

 (Formula 3) Tensile strength of tube TS X Cross-sectional area of tube

 34. If the measured load is less than or equal to the calculated load, it is determined that continuation is possible, and processing is continued. On the other hand, if the measured load is greater than the calculated load, it is determined that a splicer is not used, and processing is interrupted. 33. The stable manufacturing method for a high-precision pipe as described in 33, wherein the die and / or the plug is replaced with another one having a different shape corresponding to the same product pipe size, and then processing is resumed.

 3 5. The method for stably manufacturing pipes according to the above-mentioned 34, wherein the dies and / or plugs used after the replacement are smaller in angle than the dies and plugs before the replacement.

 36. Before punching, a lubricant shall be applied to the raw tube, and the type of the lubricant shall be changed only when the measured load exceeds the calculated load. 5. The stable production method for high dimensional precision pipes described in any of (1) to (5).

 3 7. It has a plug that can be eroded all around the surface of the metal tube, a die with holes that can be eroded all around the outer surface of the tube, and a tube pushing machine that pushes the tube. A manufacturing apparatus for a high-dimensional precision pipe, characterized in that it is possible to perform a punching operation in which the plug is inserted into the pipe and the pipe is pushed into the hole of the die by the pipe pressing machine.

 38. The apparatus for manufacturing a highly dimensionally accurate tube according to item 37, wherein the die is an integrated die and / or a fixed die.

3 9. It is characterized in that the plug is a floating plug 3 7 or 3 8. 2. A high-precision pipe manufacturing apparatus according to claim 1.

 40. The apparatus for manufacturing a high-precision pipe according to any one of 37 to 39, wherein the pipe pressing machine continuously presses the pipe.

 41. The apparatus for manufacturing a high-dimensional precision pipe according to any one of 37 to 39, wherein the pipe pushing machine presses the pipe intermittently.

 4 In 2.3.7, in the method of manufacturing a high-precision pipe in which a plug is inserted into the pipe to make it float, and the pipe is punched out by inserting the pipe into the die either intermittently or intermittently. Die of double bushes of different types are arranged on the same circumference, and one of these dies is moved in the circumferential direction of the arrangement according to the product dimensions, placed in the pass line and used for punching A high-efficiency manufacturing method for a high-dimensional precision tube.

 4 In 3.3.7, in a method of manufacturing a high-dimensional precision pipe, a plug is inserted into a pipe to make it float, and the pipe is continuously or intermittently pushed into a die and punched out. It is characterized in that a plurality of dies having different sizes are arranged on the same straight line, and any one of these dies is moved in the linear direction of the arrangement according to the product dimensions, placed in the pass line, and used for punching. High-efficiency manufacturing method for high-dimensional precision pipes.

 4 4. When changing the product dimensions between the front pipe and the next pipe, after pushing out the front pipe, stop the next pipe at the die entry side, and before or after or during the movement of the die according to the product dimensions of the next pipe. In addition, a plug according to the dimensions of the product is inserted into the next pipe, and the high-efficiency manufacturing method of the high-precision pipe described in 4 2 or 4 3.

 In 4.5.3., The die for passing the pipe, the pushing machine for pushing the pipe into the die of the pass line と, and a plurality of dies are supported in the form of being arranged on the same circumference and conveyed in the circumferential direction. Efficient production equipment for high dimensional precision tubes having any one of the dies in the pass line.

 In 4.6.3.7, the die that passes the pipe, the pusher that pushes the pipe into the die of the pass line. 內, and a plurality of dice that are supported in the same straight line and conveyed in the linear direction A high-efficiency manufacturing equipment for high-dimensional precision pipes that has a die straight-running table that arranges one die in a pass line.

In 4.7.5, in a method for manufacturing a high-precision pipe in which a plug is inserted into a pipe to float the pipe, and the pipe is pressed into a die and punched out, the pipe is disposed near the die exit side. Pass the pipe on the die exit side through a hole mold whose position in a plane perpendicular to the pipe direction is pre-adjusted. And a method for manufacturing a high-dimensional precision pipe characterized by preventing bending of the pipe.

 48. The method for producing a highly dimensionally accurate tube according to claim 47, wherein the tube on the die entrance side and / or the tube exit side is passed through a guide cylinder.

 49. The method for manufacturing a high-precision pipe described in 47. or 48., characterized in that the pipe is continuously pressed into a die.

 50. 37. In the apparatus for manufacturing a high-precision pipe having a die for passing a pipe and a pushing machine for pushing the pipe into the die, a die for passing a pipe is provided immediately adjacent to the die exit side. A fine bend adjusting means having a support substrate movably supported in a plane perpendicular to the pipe passing direction and a hole type moving mechanism supported by the support substrate to move the hole type is provided. And high-precision pipe manufacturing equipment.

 51. A method in which the hole-type moving mechanism pushes one or more points of the hole-shaped outer peripheral portion in a direction orthogonal to the tube-passing direction through a tapered surface of a wedge-shaped mold that moves in the tube-passing direction. 50. The apparatus for manufacturing a high-precision pipe according to the item 50.

 52. The apparatus for manufacturing a high-precision tube according to 51, wherein the movement of the wedge-shaped mold is urged by a screw.

 '53. The method according to claim 50, wherein the hole-type moving mechanism is of a type that pushes or pulls one or two or more portions of the hole-shaped outer peripheral portion in a direction perpendicular to a pipe passing direction. Manufacturing equipment for precision pipes.

 54. The push or pull type push or pull is urged by a fluid pressure cylinder.

 55. The apparatus for manufacturing a high-precision pipe according to any one of 50 to 54, wherein a diameter of the hole is equal to or larger than an outlet diameter of the die.

 56. The apparatus for manufacturing a high-precision pipe according to any one of 50. to 55., wherein the hole is a straight hole or a tapered hole.

 57. The apparatus for manufacturing a high-precision pipe according to any one of 50 to 56, further comprising a guide cylinder through which the pipe on the die entrance side and / or the pipe bend fine adjustment means exit side is passed.

 58. The apparatus for manufacturing a high-precision pipe according to any one of 50 to 57, wherein the pusher is a continuous pusher capable of continuously pushing a pipe.

59. In the line of manufacturing equipment for high-precision pipes with the stamping equipment described in 37. There is a pipe end grinding device that grinds the pipe end face at right angles to the pipe axis direction, a lubricant dip coating tank that dips and applies a lubricant to the pipe, and a drying device that dries the pipe coated with lubricant. And a punching device are arranged in this order.

 60. The high-precision pipe manufacturing equipment line according to 59, wherein a cutting device for cutting the pipe into a short length is arranged on an inlet side of the pipe end face grinding apparatus.

 6 1. In place of the lubricant dip coating tank and the drying device, a lubricant spray coating device that sprays and applies a lubricant to a tube, or a lubricant is sprayed and applied to a tube on the die entry side of the punching device. A row of high-precision pipe manufacturing equipment as described in 59. or 60., characterized in that a lubricant spray coating and drying device for drying after drying is arranged.

 6 2. A die exchanging device for exchanging the dice, a plug exchanging device for exchanging the plug, a bend preventing device for preventing bending of the tube on the die exit side, which is provided along with the punching device. A row of high-precision pipe manufacturing equipment described in any of 59 to 61, characterized in that two or more pipes are arranged. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is an explanatory diagram showing an embodiment of the punching used in the present invention.

FIG. 2 is an explanatory view showing a conventional drawing embodiment.

FIG. 3A is an explanatory view showing an embodiment of a conventional rotary die forging machine in which a split die is mounted and rocked, and is a cross-sectional view including a pipe central axis.

FIG. 3B is an explanatory view showing an embodiment of pushing by a conventional rotary die forging machine in which a split die is mounted and swings, and is a view taken in the direction of arrows AA.

FIG. 4 is a characteristic diagram showing the relationship between the stress in the fatigue test and the number of times of endurance.

FIG. 5 is a vertical cross-sectional view showing an example of the present invention in which a jar is used as a pipe feeding means. FIG. 6 is a longitudinal sectional view showing an example of the present invention using endless pelt as a pipe feeding means.

FIG. 7 is a longitudinal sectional view showing an example of the present invention using an intermittent feeder as a pipe feeding means. FIG. 8 is a longitudinal sectional view showing an example of the present invention in which a hole type roll is used as a pipe feeding means. FIG. 9 is an explanatory diagram of a taper angle of a plug portion.

FIG. 10 is a cross-sectional view showing an outline of the punching process.

FIG. 11 is a schematic diagram showing an embodiment of the method of the present invention using the first example of the device of the present invention. FIG. 12 is a schematic diagram showing an embodiment of the method of the present invention using the second example of the device of the present invention. FIG. 13 is an explanatory diagram of a comparative example (manually replacing the dice).

FIG. 14 is a perspective view showing one embodiment of the present invention.

FIG. 15 is a plan view showing an example of the tube bending fine adjustment means according to the present invention.

FIG. 16 is a cross-sectional view showing one example of the hole-type moving mechanism according to the present invention.

FIG. 17 is a perspective view showing one embodiment of the present invention.

FIG. 18 is a plan view showing an example of the tube bending fine adjustment means according to the present invention.

FIG. 19 is a perspective view showing one of the comparative examples.

FIG. 20 is a perspective view showing one of the comparative examples.

FIG. 21 is a perspective view showing one of the comparative examples.

FIG. 22 is a schematic diagram showing an arrangement of equipment rows according to an embodiment of the present invention.

FIG. 23 is a schematic diagram showing the arrangement of the equipment rows and the pretreatment steps required for drawing as a comparative example. BEST MODE FOR CARRYING OUT THE INVENTION

 In the conventional cold drawing method, when a metal tube was pulled out using a die and a plug, it was difficult to improve the dimensional accuracy of the tube. The reason for this is that the pulling force acts as tension, resulting in insufficient contact between the die and the pipe outer surface and between the plug and the pipe inner surface inside the working tool. As shown in Fig. 2, by inserting the plug 1 into the pipe 5 and pulling the pipe 5 out of the hole of the die 2, the pulling force 9 applied at the exit side of the die 2 allows the pipe 5 to be inserted inside the processing pipe. As a result, tensile stress is generated, and concavities and convexities are generated on the inner and outer surfaces of the pipe from the entrance to the machining tool toward the exit side, and the number increases. In addition, on the inlet side in the processed pite, the inner surface of the pipe deforms along the plug 1 so that the outer surface of the pipe does not contact or only slightly contacts. At the outlet side in the machined pile, the outer surface of the tube contacts the die 2 and deforms, so the surface of the tube does not contact or only slightly contacts. For this reason, there were portions that could be freely deformed on both the inner and outer surfaces of the pipe, and the irregularities could not be sufficiently smoothed, and the dimensional accuracy of the pipe obtained after drawing was low.

In contrast, in the punching method of the present invention, as shown in FIG. 1, the plug 1 is inserted into the tube 5 し て, and the tube 5 is pushed into the hole of the die 2 and passed therethrough. Due to the pushing force 8 applied on the entry side of the die 2, a compressive stress acts on the entire inside of the machining tool. As a result, the pipe 5 has the same cross-section as the plug 1 and the die 2 on both the entry and exit sides of the Within the whole area in the circumferential direction! : Sufficient contact. Moreover, even with a small diameter reduction ratio, the inside of the machined pipe is subjected to compressive stress, so that the pipe and the plug, and the pipe and the die are in direct contact with the entire circumferential direction within the same cross section as compared with the drawing. For this reason, the pipe is easily smoothed, and a pipe with high dimensional accuracy can be obtained.

 As a result, when comparing the fatigue strength of these pipes, a pipe manufactured by punching can obtain a sufficient target fatigue strength as compared with a pipe manufactured by conventional drawing. Also, in the case of punching, even if the shrinkage rate is small, the inner and outer surfaces of the pipe can be smoothed, so that the processing distortion is not larger than in the case of drawing, so that the heat treatment load after diameter reduction is lighter and the manufacturing cost is lower. Is lower.

 In the press-fitting using the conventional rotary forging machine 8 shown in Fig. 3, a step is generated because the die is swung 12 using a split die 9 obtained by dividing an integrated type in the circumferential direction. However, in the present invention, such a step is not generated at all, and as a result, the inner and outer surfaces of the pipe can be smoothed, and sufficient fatigue strength can be obtained. Obtainable. In the present invention, for example, a step may be eliminated as an integrated die, or a step due to swing rotation may be prevented as a fixed die. Of course, the dice may be formed as an integral and fixed die to prevent the step.

 Further, in the present invention, the structure of the apparatus can be simplified as compared with a conventional method of swinging a die using a single tally forging machine, and a sufficient load can be applied to processing. Sufficient machining is possible even when the load on the output side is increased to be equal to or less than the thickness on the die entry side. A pipe with good and sufficient fatigue strength can be obtained.

 Conventionally, as a method of reducing the deviation of the outer diameter, the inner diameter, and the thickness deviation in the circumferential direction of a metal pipe to 3.0% or less, a method by machining (processing with partial removal of material) is known. Machining costs were high, work efficiency was poor, and it was difficult to machine long, small-diameter metal tubes. Therefore, it is difficult to apply it to drive shafts of automobile parts.

-As a method of distinguishing the machined metal pipe from the metal pipe (as-punched metal pipe according to the present invention), the surface of the metal pipe is blackened by heating, rolling, etc. in the pre-manufacturing process. While the surface of the machined material has had the black scale removed, there is a method of observing the condition of the tube surface, which can be identified by this method.

Furthermore, the metal pipe is pressed by pressing the steel pipe into a die using a conventional single-tally forging machine. The thickness deviation is several times better than that manufactured by the method (for example, see Patent Documents 1, 2, and 3). In other words, in the past, there was no steel pipe that had been punched out and had any one or more of the outer diameter deviation, radial deviation, and circumferential wall thickness deviation of 3.0% or less. In the present invention, the outer diameter deviation, the inner diameter deviation, and the circumferential thickness deviation, which are indicators of the dimensional accuracy, are obtained as follows.

 The outer diameter (or 內 diameter) deviation can be calculated from the circumferential distribution data of the outer diameter (or inner diameter) measured by rotating the tube with the micrometer in contact with the outer surface (or 內 surface) of the tube. Or the maximum deviation from the target inner diameter) or from the circumferential distribution data of the distance between the tube and the laser oscillation source measured by applying the laser beam to the outer surface (or inner surface) of the tube, The maximum deviation from the target inner diameter is calculated. Alternatively, the outer diameter (or inner diameter) deviation may be determined by calculating the deviation from the true circle in the circumferential direction by analyzing the cross section in the circumferential direction of the pipe.

 The wall thickness deviation in the circumferential direction can be calculated as the difference between the above outer diameter <circumferential distribution data and the above inner diameter distribution data in the circumferential direction, or by analyzing the cross section of the pipe in the circumferential direction using the wall thickness. It is measured directly from the cross-sectional image as the maximum deviation from the target thickness.

 The measurement shall be made at an arbitrary position except 150 from the leading and trailing ends of the pipe; at a pitch of 10 mm or less, and shall be determined from the values of 10 or more measuring points.

 That is, outer diameter deviation, inner diameter deviation and thickness deviation (-circumferential thickness deviation) are defined as follows.

 Outer diameter deviation: (maximum outer diameter-minimum outer diameter) Target outer diameter (or average outer diameter) X 100 (%) Inner diameter deviation: (maximum diameter-minimum diameter) / target inner diameter (or average inner diameter) X 100 ( %) Thickness deviation: (maximum thickness-minimum thickness) / Target thickness (or average thickness) X 100 (%) The high dimensional accuracy pipe of the present invention has the three dimensional accuracy index of-or two or more. Since the metal pipe is 3.0% or less, it can be used as a metal pipe for driving system parts for automobiles that require high dimensional accuracy of 3.0% or less.

 In addition, in the conventional rotary forging press-in method shown in FIGS. 3A and 3B, since the die 4 is used as a divided object and oscillated 12, the step due to the die division or under a high stress is used. Due to non-uniform deformation due to the different stiffness of the dies in the circumferential direction, the circumferential thickness deviation could not be made sufficiently good.

In contrast, in the punching of the present invention, the die does not need to be rocked as a single piece. Therefore, non-uniform deformation does not occur, and as a result, the inner and outer surfaces of the pipe can be smoothed. Furthermore, in the conventional rotary forging and indentation method, it is necessary to feed the pipe 5 in conjunction with the rotation 1 and 2 of the die 4, so that the swing speed cannot be increased to a certain level due to the impact load limit of the die. Low efficiency. Also, in conventional drawing, it is necessary to apply a tension by strongly sandwiching the end of the tube.Therefore, it is necessary to draw out the tube by narrowing the end of the tube. It was remarkably low.

 On the other hand, in the present invention, in order to push the plug and float the plug, it is possible to apply a pushing force 15 to the pipe from the die entry side by using the pipe feeding means 3 to continuously feed the pipe into the die. It is possible. Processing with much higher efficiency than before can be achieved. Here, "continuous feeding" refers to feeding a pipe 5 and the next pipe 5 without interruption, as shown in Fig. 1, and the pipe body is moved in the pipe direction. May be continuous movement or intermittent movement that minimizes downtime.

 Preferred examples of the pipe feeding means 3 include a crater 13 for gripping the pipe 5 before processing (a piece of small pieces for gripping the pipe connected in an endless track; see FIG. 5), and an endless belt for holding the pipe 5 before processing. 1 4 (see Fig. 6), intermittent feeder 15 (see Fig. 7) that grabs the tube before processing and alternately intermittently feeds it. Pore-forming roll 16 (see Fig. 8). The pipe feeding means 3 may be configured by combining one or more of these.

 The pipe feeding means is optimally selected depending on the pipe size (diameter, length, wall thickness), the force required to punch the pipe, the length required for the pipe after punching, etc. It is also important to ensure the necessary punching force while preventing flaws when pinching or pressing.

 In addition, when sandwiching the pipe before processing with the grooved rolls, if two or more rolls are used and Z or two or more rolls are set up, the pipe may be damaged. This is preferable because it is easy to secure a pull-out force without using the same.

 In addition, when the plug is floating, the plug is always in a position where the compressive stress is applied stably even if the die and plug angle and the punching conditions involving the lubrication of the surface of the die plug are varied. Since it is present, good dimensional accuracy can be obtained stably.

Also, when producing high dimensional precision pipes, lubrication between the outer surface of the plug and the inner surface of the pipe and between the inner surface of the die and the outer surface of the pipe does not cause defects such as seizures on the pipe surface during processing. Can be manufactured. Furthermore, since the frictional force is reduced by lubrication, the load required for machining can be reduced, saving machining energy and improving production efficiency.

 As a result of studying various lubrication methods, the inventors have found the following method, which is a requirement of the present invention. That is, punching is performed by forming a lubricating coating on one or both of the inner and outer surfaces of the pipe in advance. As the lubricant used for forming the lubricating film, any of a liquid lubricant, a grease-based lubricant, and a drying resin is preferable. Examples of the liquid lubricant include mineral oil, synthetic esters, animal and vegetable oils and fats, and mixtures of these with additives. Examples of grease-based lubricants include Li-based grease lubricants, Na-based grease lubricants, and those containing additives such as molybdenum disulfide. Examples of the drying resin include a polyacrylic resin, an epoxy resin, a polybutyl resin, and a polyester resin.

 The method of forming a lubricating film using the resin is as follows. The tube is coated with the resin, a liquid obtained by diluting the resin with a solvent, or an emulsion of the resin. And drying with hot air, or air drying. Examples of the solvent for diluting the resin include ethers, ketones, aromatic hydrocarbons, straight-chain / side-chain hydrocarbons, and the like. Examples of the dispersion medium for obtaining the resin emulsion include water, alcohols, and mixtures thereof.

 In order to produce pipes with high dimensional accuracy more efficiently, hot-rolled steel pipes that have been electro-welded as hot rolled steel pipes or seamless steel pipes that have been heated in a furnace are processed as they are without removing oxide scale. Good, and this can reduce processing costs.

 In the conventional cold-pulling method, one-for-one-tally forging and indentation method, only diameter reduction is performed. It was almost impossible to produce pipes of the same outer diameter with different degrees of processing, because only a unique degree of processing could be obtained from the same size of raw pipe. On the other hand, in the present invention, as shown in FIG. 1, the plug 1 has an expanded portion 1A for expanding the tube 4 and a reduced diameter portion 1 for reducing the diameter of the expanded tube 4 in cooperation with the die 2. B is provided. This makes it possible to manufacture tubes of a certain size with different working rates by using raw tubes of the same size. Even if the size of the base tube and the tube after the punching process are constant, the expansion ratio of the plug expansion part will inevitably increase or decrease only by adjusting the expansion ratio of the plug expansion part. This is because the degree of processing of the separated pipes differs.

 Expansion rate = 1-1 D O Z D 1

Diameter reduction = 1-D 2 / Ό 1 However,

 D 0: outer diameter of Qin pipe,

 D 1: Target outer diameter after expansion

 D 2: Target outer diameter after diameter reduction

 In the present invention, from the viewpoint of increasing the production efficiency, it is preferable that tubes are successively supplied to the die in a continuous manner. In this case, if the plug is supported from the die entry side or the exit side, the means such as par and wire used for the support will be an obstacle, and it will be difficult to supply the pipe with a different gun. Therefore, the plug is preferably floated in the tube. In addition, in order to stably perform the punching according to the present invention, it is necessary to stabilize the plug during processing. In other words, it is necessary to prevent deviation from an appropriate position with respect to the die. This point was discussed. The plug receives a surface pressure from the pipe by expanding and reducing the diameter. It was found that if the surface pressure on the reduced diameter side was larger than that on the enlarged diameter side, the plug could be stabilized. To increase the surface pressure on the reduced diameter side more than that on the enlarged diameter side, as shown in Fig. 9, the taper angle 0A of the expanded part 1A of the plug 1 is changed to the taper angle 0A of the reduced diameter part 1B. It is effective to set the angle to less than θB. Here, the taper angle of the plug portion means an angle formed between the surface of the portion and a straight line 17 parallel to the center axis of the plug along the traveling direction of the tube. Preferably, 0 A = 0.3 to 35 ° and 0 B == 3 to 45 °. The other is to make the diameter reduction ratio larger than the expansion ratio. For that purpose, it is effective to make the outer diameter of the pipe on the exit side of the die smaller than the outer diameter of the pipe on the entrance side.

 In the present invention, since an integral fixed die can be used, a step due to the dicing and uneven deformation in the circumferential direction do not occur at all. As a result, both the inner and outer surfaces of the pipe can be smoothed. Further, by using the integral fixed die, a sufficient load can be applied to the processing. By setting the thickness on the die exit side to be equal to or smaller than the thickness on the coterie side, sufficient machining is possible even if the load increases. As a result, a pipe having good dimensional accuracy can be obtained. The range of product pipe sizes that can be manufactured from one raw pipe size is expanded.

However, in order to perform punching stably, it is necessary to use plugs and dies that satisfy the requirements found by the inventors. The requirement is that the angle between the surface of the reduced diameter part of the plug and the machining center axis (the angle of the reduced diameter part) is 5 to 40 °, and the length of the same part (the length of the reduced diameter part) is 5 to 100 mm, and the angle (the die angle) between the inner surface of the hole on the die entrance side and the processing center axis is 5 to 40 °. Preferably further, the plug The length of the bearing (the length of the plug bearing) should be 5-20 Omm. Here, the processing center axis means an axis perpendicular to the diametric cross section of the plug and passing through the center of the same cross section for a plug, and an axis perpendicular to the diametric cross section of the die hole and passing through the center of the same cross section for a die. The bearing portion means a column portion connected to the minimum diameter portion of the reduced diameter portion. The reasons for specifying the plug dies as described above are as follows. (Brag reduction angle: 5 to 40 °)

If the angle of the plug reduced diameter is less than 5 °, the plug may come off together with the material (: tube), while if the angle of the plug reduced diameter exceeds 40 °, , in some cases force ^s plug and the material can not be a punching processing press Oshitsuma' to die

 (Length of the reduced-diameter portion of the plug: 5 to: L0Omm)

 If the reduced diameter of the plug is less than a-5 mm, the plug may come off with the material, while if the reduced diameter of the plug exceeds 10 Omm, the plug and In some cases, the frictional force with the material is increased and both are pressed into the dies and cannot be punched out.

 (Die angle 5 ~ 40

When the die angle is less than 5 ^0, if the cormorant want missing to be plug and because Ri elaborate remain material to the material and there is, on the other hand, if the dice angle and 4 0 ° than, plug and materials However, there are cases in which the die is pressed into the die and punching cannot be performed.

 (Plug bearing length: 5 to 200 mm)

A force is applied to the plug to pull it out of the die due to the reaction force from the material and the die applied to the reduced diameter part. It is necessary to stabilize the plug by applying a pushing force. A good way to do this is to provide a bearing on the plug and use the frictional forces acting on this surface. According to the studies by the inventors, in order to contribute to the sufficient stabilization of the plug by using this frictional force, the length of the plug bearing portion is preferably set to 5 to 200 mm. If the length of the plug bearing is less than 5 mm, the frictional force to push out the plug will be insufficient, and the plug will be easily pushed back to the die entry side due to the reaction force of the material die. If the length of the ring is more than 20 O mm, the frictional force is too large. Therefore, the plug is easily pushed out to the die exit side, and in any case, the position of the plug becomes unstable.

 Further, in the present invention, by floating the plug, a stable compressive stress state can always be obtained even if the die and plug angles and the punching conditions involving the lubrication of their surfaces are complicatedly changed. The plug can be placed in the position where Further, it is preferable to set the thickness of the die on the exit side to be equal to or less than the thickness of the entrance side, because the stability of the punching process is further improved.

 During the punching process, the plug is stuck in the tube and the load increases, and as a result, the pushed-in tube may buckle, making it impossible to perform the process. It is necessary to prevent buckling of the tube beforehand. Therefore, the present inventors focused on the load at the time of punching. In other words, when the plug is tightly packed, the load in the direction of punching increases significantly, so if this load is below a certain value, punching is possible. If not, it is necessary to change the punching conditions to the optimal ones. This specific value is referred to as a punching limit load. If pushing is impossible, the tube to be pushed in will buckle, so if the pushing limit load is set from the formula that expresses the buckling of the tube, pushing can be performed stably with a load less than this. . Although the Euler equation obtained from the elastic modulus of the material is well known as the equation representing the buckling of the tube, the inventors' study showed a value far from the actual phenomenon and could not be applied at all. Therefore, as a result of examining various buckling formulas different from this, it was found that the following formula 4 best represents the actual phenomenon.

(Equation 4) .ff _fc X

 here,

σ _k = YSX (1-a X λ),

 λ = (L / n) / k,

 a = 0.00 1 85 to 0.01 5 5,

 L: Hata length,

 k: Secondary radius of section,

k ² = (d + ² ) / 1,6

n: Tube end condition (ιι = 0.25-4), d !: Outer diameter of raw pipe,

 d2: Inner diameter of raw pipe,

 Y S: Yield strength of pipe

 To make it possible to perform punching stably, if the measured punching direction load (measured load) does not exceed the value of Equation 4 (calculated load), the punching should be continued as it is. If it exceeds, the punching can be interrupted and interrupted, and the conditions can be changed and the punching can be restarted.

 However, Equation 4 is somewhat complicated, and if it is desired to make a simpler determination, the following Equation 5, which is a simplified version of Equation 4, may be used.

 [Equation 5] Yield strength of pipe Y S X Cross-sectional area of pipe

 Equation 5 shows the maximum push-out limit load about 10% larger than Equation 4, but the present inventors have found that the determination can be made sufficiently simply.

 Also, when punching a very short tube (for example, about 0.2 m or less), or at a stretch, even if the tube is slightly buckled, increase the processing speed and increase the load until the die does not break. In such cases, the following equation 6 may be used.

 [Equation 6] Tensile strength of pipe T S X Cross-sectional area of pipe

 The above measurement load (actual load in the punching direction) can be measured by using a load cell installed on a punch for punching, or by using a die cell that floats a die from a stand and is integrated with the die. The preferred method is to measure. If the measured load exceeds the calculated load calculated by any of Equations 4 to 6, that is, if it is determined that machining is not possible, the punching process is interrupted and the die is stopped. After replacing the plug and / or plug with another shape corresponding to the same product pipe size, it is advisable to resume machining. Here, since dies and / or plugs of other shapes corresponding to the same product pipe dimensions process the same Hata pipe, they may be selected from those set to the same diameter reduction rate. .

 According to the study of the present inventors, it is preferable to make the angles of the dies and plugs used after the replacement (see FIG. 10) smaller than those before the replacement in order to obtain more stable processing conditions. It turned out that there was.

To achieve more stable processing conditions, the type of lubricant applied to the pipe You can change the kind. From the viewpoint of simplicity, when applying lubricant by immersing the tube in the lubricant in the coating tank, it takes time and effort to replace the lubricant in the coating tank. It is difficult to make changes frequently. Therefore, it is important to conduct experiments beforehand and select a lubricant with good performance that can significantly reduce the load in the punching direction.

 On the other hand, in the case of the punching according to the present invention, as shown in FIG. 1, the plug 1 is inserted into the tube 4 and the tube 4 is pushed into the hole of the die 2 and passed therethrough. Here, the plug is capable of contacting the entire inner circumference of the pipe inside the welded pipe, and the hole is capable of contacting the entire outer circumference of the pipe inside the processed pite. Due to the indentation force 11 applied on the entry side of the die 2, a compressive stress is applied to the entire processing pipe portion. As a result, the pipe 4 can sufficiently contact the plug 1 and the die 2 on either the inlet side or the outlet side in the processing pile. In addition, even with a small diameter reduction ratio, the inside of the machined tool is subjected to compressive stress, so that the pipe and the plug and the pipe and the die are more likely to come into contact with each other compared to drawing, and the pipe is easy to smoothen, and high dimensions A pipe with high accuracy can be obtained. In the case of punching, the inner and outer surfaces of the pipe can be smoothed even if the diameter reduction ratio is small, and the processing distortion is smaller than in the case of drawing, so the heat treatment load after diameter reduction is light or heat treatment. Can be omitted, and the manufacturing cost is reduced.

 Therefore, the configuration of the apparatus of the present invention includes a plug 1 capable of contacting the entire inner surface of the metal tube 4, a die 2 having a hole capable of contacting the entire outer surface of the metal tube 4, and a tube pusher for pressing the same tube 4. A metal pipe 4 is inserted into the hole of the die 2 by the pipe pressing machine 3 in a state where the plug 1 is inserted in the pipe 內.

 In addition, in the press-in using the conventional rotary forging machine 8 shown in FIG. 3, a split die 9 obtained by dividing an integral type in a circumferential direction is used, and the split die 9 is further oscillated 12. Due to unevenness caused by unevenness due to the steps caused by the unevenness of the dies or circumferentially different dies under high stress, the wall thickness accuracy could not be sufficiently improved. On the other hand, in the apparatus according to the present invention, which is configured to be able to perform the punching, the metal pipe is passed through the hole of the die having the hole in contact with the entire outer circumference of the pipe in the same cross section, so that the apparatus is formed by the split die. Such a step does not occur at all, and as a result, the inner and outer surfaces of the pipe can be smoothed.

Further, in the present invention, an integrated fixed die is used as the die. The structure of the apparatus can be simplified as compared with a conventional method using a split die mounted on a rotary forging machine. A sufficient load can be applied to the processing. Even if the load is increased by setting the thickness equal or less, sufficient processing is possible. A metal tube with extremely good dimensional accuracy can be obtained in a wide range of product requirements.

 In the present invention, the plug is floated. Even if the punching conditions, such as the die and plug angles, lubrication of the die and plug surfaces, fluctuate in a complicated manner, the plug is always located in a place where compressive stress is applied stably. Therefore, good dimensional accuracy can be obtained stably.

 Furthermore, in the conventional drawing, it was necessary to pull down the tip of the pipe and pull that part, and the pipe had to be processed in a single shot. On the other hand, in the present invention, since the tube is pushed, it is not necessary to shrink the tip of the tube, and the tube can be pushed one after another. If the plug is floated, continuous punching will be possible, which will significantly improve productivity. In addition, when the length of the pipe is short, it is possible to manufacture a pipe with high dimensional accuracy while maintaining high productivity by using a pipe pushing machine that performs an intermittent pushing operation. The tube pushing machine may support and push the body of the tube, or may push one end of the tube.

 Pipes that require stamping have a wide variety of product dimensions. To change the outer diameter of the product during punching, it is necessary to prepare a die with a different hole shape and replace the die each time the outer diameter of the product is changed. The die size of a die is usually represented by a diameter, an angle, and a taper length.

 However, the outer diameter of the product is different for each small lot with a minimum unit of several tons, and each time it is changed, it is necessary to remove the previously used die and install the next die. The mounting accuracy of the unit was strict on the order of ± 0.1 mm, requiring considerable time and effort.

 The inventors of the present invention have found that in order to reduce the time and labor required for the exchange of dies, it is only necessary to prepare dies of various hole types according to the outer diameter of the product, arrange them, and exchange them sequentially. I found it.

In a method of manufacturing a high dimensional precision pipe, in which a plug is inserted into a pipe to make it float, and the pipe is continuously or intermittently pressed into a die and punched out, a plurality of dies having different hole types are formed on the same circumference. Arrange. Only hole-shaped dies corresponding to the target product dimensions are rotated in the circumferential direction of the array, placed in the pass line, and used for punching. If the target product dimensions of the next pipe are different from those of the front pipe, rotate the hole-shaped die corresponding to the outer diameter dimension in the same way, place it on pass line S, and use it for punching. do it. For example, as shown in Fig. 11, for example, as shown in Fig. 11, a die 2 for passing the tube 4, a pusher 2 for pushing the tube 4 into the die 2 in the pass line, and a plurality of dies 2, 20, , 20 are supported in the form of being arranged on the same circumference, and are conveyed in the circumferential direction. This can be easily performed by using an apparatus having a die turntable 19 for arranging any one of the dies 2 in the pass line.

 On the other hand, a plurality of dies with different hole types are arranged on the same straight line, and one of these dies is moved in the linear direction of the arrangement according to the product dimensions and placed in the pass line. Then, it may be used for punching.

 This is, for example, as shown in FIG. 12, a die 2 for passing a tube 4, a pusher 2 for pushing a tube 4 into a die 3 in a pass line, and a plurality of dies 2, 20,. Are arranged in the same straight line and conveyed in a straight line direction. This can be easily carried out by using an apparatus having a die straight platform 23 for arranging any one of the dies 2 in the pass line.

 In addition, plugs need to be inserted efficiently. Efficiency is further improved if plugs can be easily replaced during die replacement. The plug 1 used in the previous processing is left behind in the die 內, so it is removed when the die is replaced. It would be nice to be able to insert the necessary plugs 22 into the tube during the die change.

 For this purpose, in either of the first and second methods of the present invention, when changing the product dimensions between the front tube and the next tube, after the end of the punching of the front tube, move the next tube to the die entry side. Stop. It is preferable to insert a plug 22 corresponding to the product size into the next pipe before, during, or after the die is moved according to the product size of the next pipe. As a result, not only dies but also plugs can be exchanged efficiently.

 When punching is performed, the tube on the die exit side is easily bent. If the pipe is bent, the pipe will not be a product, so it is necessary to have a technology to process the pipe without bending it. With conventional drawing, processing is performed while applying tension one by one across the end of the pipe on the die exit side, so processing efficiency is low, but the pipe is guided in the drawing direction and is difficult to bend. However, in the case of punching, the pipe on the die exit side is free to move, and the pipe can be easily formed due to the processing accuracy of the die, the wall thickness accuracy and surface condition of the pipe before processing, and the uneven lubrication of the die and plug. Bends. For this reason, there has been a strong demand for a technique for preventing the pipe on the die exit side from bending.

Then, the present inventors conducted an experiment in which guide tubes were provided on the entrance side and exit side of the die and guided through the tubes with respect to the bending of the tube after punching. If the guide tube is provided on either the entrance side or the exit side of the die, the tube will not bend easily, and if it is provided on both, the tube will be harder to bend Also, the position of the guide tube becomes harder to bend as it is closer to the die exit.

 Therefore, it is preferable to install the guide tube in the vicinity of the die entrance side and the die exit side. In other words, it should be installed on the die exit side and very close to the die. However, it was found that the bending could not be prevented sufficiently depending on the bending direction of the pipe. In order to sufficiently prevent bending regardless of the bending direction of the pipe, it is necessary to make the gap between the outer surface of the pipe and the inner surface of the guide cylinder almost zero. However, it turned out that there was a problem that the pipe was in contact with the guide cylinder too much to cause flaws, and the punching force was significantly increased.

 The present inventors have found that the bend of the tube has already started just before the die exit side. That is, residual stress is generated in the pipe due to the processing accuracy of the dies, the wall thickness accuracy and surface condition of the pipe before processing, and the uneven lubrication of the dies and plugs, and this residual stress is rapidly released near the die exit side. Therefore, bending is likely to occur. Therefore, if means for finely adjusting the bending direction of the pipe is provided in the immediate vicinity of the die exit side, the bending of the pipe can be sufficiently prevented.

 As a result of intensive studies by the present inventors, a hole type for passing a pipe, a support substrate for movably supporting the hole type in a plane orthogonal to the pipe direction, and a support substrate, The pipe bending fine-adjusting means having a hole-type moving mechanism for moving the hole-type mold while being supported by the apparatus is provided. By using the hole-type moving structure to slightly move in the plane of the support substrate and finely adjusting the position in a plane perpendicular to the pipe passing direction in advance, the tube on the die exit side is passed through the tube. It was understood that the bend could be sufficiently prevented.

 To fine-adjust the hole position, for example, use multiple dummy tubes before actual production, perform a punching experiment at several different hole positions, measure the bending of the tube, and change the hole position. Find the relationship between the minute and the variation in the bending of the tube after punching. If the bend of the pipe is likely to exceed a predetermined threshold during actual production, a method is preferred in which the die is moved to an orientation where the bend becomes smaller based on the above relationship.

 The hole-type moving mechanism is, for example, a method in which one or more points on the outer periphery of the hole-type die are pushed in a direction perpendicular to the tube direction through a tapered surface of a wedge-shaped mold that is moved in the tube direction by screws. Formulas are preferred. Alternatively, it is preferable to use a hydraulic cylinder (hydraulic cylinder, air cylinder, etc.) to directly push or pull one or more points on the outer periphery of the hole-type mold in a direction perpendicular to the pipe direction.

If the hole diameter of the mold is larger than the exit hole diameter of the die, the pipe will be It is preferable because it can be processed smoothly without being clogged. In particular, it is more preferable that the diameter is within +3 mm from the diameter of the exit hole of the die + O mm because fine adjustment is easily performed. Note that the hole-type hole may be a straight hole or a tapered hole.

 In addition, naturally, the supporting substrate is provided with a hollow portion large enough to allow the pipe to pass with a sufficient gap at a position S where the pipe crosses the passage of the pipe exiting the die.

 In addition, if a guide tube is provided on the die entry side and / or the tube bend fine adjustment means exit side, the guide tube for passing the tube entering the die and / or the tube exiting from the tube bend fine adjustment means is provided, the pipe enters the die almost vertically. And / or substantially perpendicularly exits from the tube bending fine adjustment means, which is preferable because bending of the tube can be more easily prevented.

 In the present invention, it is preferable that the tube is continuously fed and pushed into the die. By sending the tubes in a row, the heat generated by friction and processing by the dies and plugs is more stable than in the case of single-shot processing, so bending can be more easily prevented. In the case of punching, as in the case of drawing, it is not necessary to form a lip for the tip of the pipe to be gripped by the drawing machine on the die exit side.Therefore, it is necessary to continuously feed the tail end of the preceding pipe with the tip of the succeeding pipe. With this, production efficiency can be increased.

 In the case of conventional drawing, a sufficient lubricating film is necessary to obtain high dimensional accuracy, and therefore, a good smooth bond treatment was performed. The method involves pre-pickling the tubes to remove any oxide scale, then washing with alcohol to neutralize the acid, and washing with water. Thereafter, the tube was immersed in a tank for performing a bond treatment to form a lubricating film, and then was immersed in a metal stone tank to form a film, and then the tube was dried with hot air. For this reason, these processes require several hours or more, and if these processes are incorporated into a line for drawing out pipes, productivity will be significantly impaired, so that they have been treated in separate processes.

 Compared to this, according to the punching process, even if the diameter reduction ratio is small, it is easy to obtain high dimensional accuracy, so that the lubrication of the pipe is simple and good. That is, the pipe does not need to be pickled, and it is sufficient to dip-coat the lubricant and then dry it with hot air. In particular, in order to perform continuous punching, the squareness of the end face of the pipe is important, and a grinding device for producing this squareness is required.

These processes before the punching process are most efficiently performed in the order of squareness of the pipe end face, lubricant dip coating, and drying. From these points, in the present invention, A pipe end surface grinding device that grinds the end surface of the pipe at right angles to the pipe axis direction, a lubricant dip coating tank that dips and applies lubricant to the pipe, and a drying device that dries the pipe coated with the lubricant are provided. Since the equipment rows are arranged in sequence on the entry side of the punching equipment, 髙 dimensional precision pipes can be manufactured efficiently.

 In addition, since it is more efficient that the perpendicularity of the pipe end face is performed immediately after the pipe is cut into a short length, the equipment row of the present invention provides a pipe having a short length at the entry side of the pipe end face grinding device. It is preferable that a cutting device for cutting is arranged at the center.

 Also, if a lubricant that easily forms a film by drying is used as the lubricant, instead of dip coating at the entrance of the punching device and then drying, it is sprayed at the die entrance side of the punching device, just near the die entry side. Then, the tube may be dried, or, if the lubricating property is better, the tube may be punched out in a wet state without drying. Therefore, the equipment line of the present invention comprises a lubricant spray coating apparatus for spraying and applying a lubricant to a pipe on the die entry side of the punching processing apparatus instead of the lubricant dip coating tank and the drying apparatus. Alternatively, a lubricant spray-coating / drying device for spraying and applying a lubricant to the pipe and then drying may be provided.

 In order to further improve the efficiency of the punching process, it is preferable that the dies and plugs can be easily exchanged online and that the pipe does not bend at the die exit side. From these points, in the equipment line of the present invention, in the equipment row of the present invention, a die exchanging device for exchanging the dice, a plug exchanging device for exchanging the plug, and a bending of the pipe on the die exit side are provided in parallel with the punching device. It is preferable that one or two or more of the bending preventing devices for preventing bending are arranged.

 The die (or plug) changer can hold a plurality of dice (or plugs) of different dimensions (and / or shapes) arranged in the order of use, and can transfer and arrange them in sequence to the specified pipe line position e. Is preferred. The bend prevention device uses, for example, a movable disk having a through hole for a tube, and can apply a force in a direction opposite to the direction in which the tube is likely to bend to the tube immediately adjacent to the die exit side. A structured one is preferred.

It should be noted that both the conventional drawing and the punching used in the present invention often require a tube with a surface that has been pickled after the application. And ship it. In the case of drawing, it is necessary to pickle the raw tube in order to form a strong lubricant film when performing the bond processing before processing, and then pickling again to remove the lubricant after drawing. Is essential and must be pickled twice. In comparison, in the case of punching, the lubrication treatment before processing can be simple and the chemical scale can be left attached, so that the lubrication treatment can be put online and incorporated into the equipment row, and the cost is low. Efficient equipment lines are possible. Example 1

 Hereinafter, the present invention will be described more specifically with reference to examples.

 In Example 1.1, a steel pipe having an outer diameter of 40 mm and a wall thickness of 6 mm was subjected to a punching process in the form shown in FIG. Here, we used a plug with a mirror-finished surface that comes into contact with the inner surface of the tube, and an integrated fixed die that had a mirror-finished surface that comes into contact with the outer surface of the tube. The plug was inserted into the pipe with one end fixed. The processing conditions were as follows: Outlet thickness = Inlet thickness, diameter reduction = 10%.

 In Example 1.2, machining was performed in the same manner as in Example 1.1, except that the diameter reduction ratio was 5%.

 In Example 1.3, processing was performed in the same manner as in Example 1.2 except that the plug was floated.

 Further, as Comparative Example 1, in the same manner as in Example 1.2 except that the punching of the form shown in FIG. 1 was replaced with the drawing of the form shown in FIG. Was performed.

 As Comparative Example 2, a split die having the form shown in FIG. 3 was incorporated into a rotary forging machine and used in place of the integrated fixed die in Example 1.2, and was used in place of the punching. Processing was performed in the same manner except that the pressing was performed.

 In addition, as Comparative Example 3, processing was performed in the same manner as in Comparative Example 2, except that the processing conditions were as follows: outlet thickness = entrance thickness + 1 碰 (= 7 sq.).

 The three-dimensional accuracy index was determined for these steel pipes after diameter reduction processing, and these steel pipes were subjected to a fatigue test. The results are shown in Table 1.

The outer diameter and inner diameter deviations shown in Table 1 were obtained by the measurement using the laser light, and the circumferential thickness deviations in the same table were obtained from the difference in the circumferential distribution of these measurement data. As shown in Fig. 4, the endurance limit of the fatigue test shown in Table 1 means that the stress level was varied in a test to determine the number of repetitions (ie, the endurance number) until cracking, while keeping the stress constant. In the graph of the relationship between stress and the number of times of endurance, as the number of times of endurance increases, the number of endurances at the inflection point at which the stress starts to decrease from a decreasing tendency to become substantially constant. That is, in the case of this example, the number of times of endurance at a stress of about 150 MPa.

 According to Table 1, the product pipes of Examples 1.1 to 1.3 had extremely good dimensional accuracy and the best fatigue strength, and especially when the plug was floating, the dimensional accuracy was even better. 13 ). On the other hand, in the conventional drawing, the dimensional accuracy of the product pipe was reduced, and the resultant fatigue strength was also significantly reduced (Comparative Example 1). Even with the rotary forging machine, the dimensional accuracy of the product pipe was reduced (Comparative Example 2), and further reduced when the pipe was thickened (Comparative Example 3), and sufficient fatigue strength could not be obtained.

Example 2

 As an example of the present invention, a steel pipe of Φ 4 O mm X 6 mm t X 5.5 mm L is used as a material, and a plug is floated and charged into the steel pipe by using a mirrored plug and an integrated fixed die. The steel pipe was pressed from the die entry side with a diameter reduction ratio of 5%, and the steel pipe on the die exit side was punched out with the same thickness of 6 mm t as the die entrance side. An intermittent feeder of the type shown in Fig. 7 was used as the pipe feeding means, and the pipes were continuously fed into the die.

 Further, as Comparative Example 1, the drawing in the form of FIG. 2 was performed. In this example, the same steel pipe was used as the material, the plug and the die were used, the plug was inserted into the steel pipe, and the steel pipe was pulled from the die exit side at the same diameter reduction rate, and the wall thickness of the steel pipe on the die exit side was determined. Was reduced to 5.5 mm t.

 Further, as Comparative Example 2, a rotary forging indentation method in the form of FIGS. 3A and 3B was performed. In this example, a rotary forging machine using the same steel pipe as the material and a split die instead of the above-mentioned integrated die was used, the plug was inserted into the steel pipe, and the rotary forging was performed at the same reduction ratio as above. The thickness of the steel pipe on the outlet side of the forging machine was increased to 7 mm t.

The dimensional accuracy (outer diameter deviation, ^ diameter deviation, wall thickness deviation in the circumferential direction) of the steel pipe manufactured by the method of each of these examples was measured, and the machining efficiency was investigated. The results are shown in Table 2. The outer diameter deviation and the inner diameter deviation were determined by image analysis of the cross section of the pipe in the circumferential direction and calculating the deviation from a perfect circle in the circumferential direction. The circumferential wall thickness deviation was directly measured as the maximum deviation from the average wall thickness from the image of the wall cross section by image analysis of the circumferential section of the pipe. According to Table 2, the steel pipe manufactured by punching of the present invention example had remarkably good dimensional accuracy and good heat efficiency. On the other hand, the steel pipe manufactured by drawing in Comparative Example 1 had a reduced dimensional accuracy. Also, the dimensional accuracy of the steel pipe manufactured by the rotary forging press of Comparative Example 2 was reduced. The processing efficiency was extremely low for both drawing and rotary forging.

Example 3

 [Comparative Example 3.1] A Φ40 mm X 6.0 mm tX 5.5 mL ERW steel pipe with hot-rolled scale adhered to the surface was punched out as shown in Fig. 1 under the following conditions A. processed.

 (Condition A) Plug: A mirror plug is inserted into a steel pipe and floated.

 Dies: Integrated fixed dies

 Diameter reduction: 5%

 Steel pipe wall thickness at die exit side: 6.0 mm t (= inlet side wall thickness)

 [Invention Example 3.1] The same steel pipe as above was processed in the same manner as in Comparative Example 1 after applying a liquid lubricant (mineral oil) to both the inner and outer surfaces thereof to form a lubricating film.

 [Example 3.2 of the present invention] A grease-based lubricant (a mixture of Li-based grease lubricant and molybdenum disulfide) was applied to the inner and outer surfaces of the same pipe to form a lubricating film. Processed as in 1.

 [Example 3.3 of the present invention] The same steel pipe as above was coated with a drying resin (polyalkyl resin) on both inside and outside and exposed to hot air (at about 200) to dry to form a lubricating film. Added in the same way as 1.

 [Example 3.4 of the present invention] The same steel pipe as above was coated on both its inner and outer surfaces with a liquid obtained by diluting a drying resin (polyalkyl resin) with a solvent (acetone), and was dried by blowing it into warm air (at about 50). After forming a lubricating coating by the same method, processing was performed in the same manner as in Comparative Example 1.

 [Example 3.5 of the present invention] Emulsion prepared by dispersing a drying resin (polyalkyl-based resin) in a dispersion medium (water) is applied to the inner and outer surfaces of the same steel pipe, and the steel pipe is dried with warm air (about 70). After forming a lubricating film, processing was performed in the same manner as in Comparative Example 1.

 [Comparative Example 3.2] After applying the same liquid lubricant as that of Example 1 of the present invention to the same and the outer surface of the same steel pipe as the above-mentioned steel pipe to form a lubricating coating, the cold drawing method shown in FIG. processed.

 (Condition B) Plug, dice, diameter reduction: Same as Condition A

Wall thickness of steel pipe on die exit side: 5.5 mm t (thickness on entry side) [Comparative Examples 3.3] After applying the same liquid lubricant as that of Example 1 of the present invention to the inner and outer surfaces of the same steel pipe to form a lubricating film, the following conditions C were obtained by the rotary forging indentation method shown in FIG. Added at.

 (Condition C) Plug: Same as Condition Α

 Dice: Split die

 Diameter reduction: Same as condition A

 Steel pipe thickness at die exit side: 7.0 oz t (> inlet thickness)

 Table 3 shows the results of measuring the surface flaw condition and dimensional accuracy (outer diameter difference, inner diameter deviation, wall thickness deviation) of the steel pipes manufactured by the methods of these examples. The outer diameter deviation and the inner diameter deviation are calculated by analyzing the cross section of the pipe in the direction of the circle and calculating the maximum deviation from the true circle (ie, (maximum minimum-minimum size) / perfect circle diameter X 100%) in the circumferential direction. It was determined by calculation. The wall thickness deviation is calculated by analyzing the cross-section of the pipe in the circumferential direction, and calculating the maximum deviation from the wall thickness cross-section image to the average wall thickness (that is, (maximum wall thickness-minimum wall thickness) no average wall thickness x 100%) Was measured directly.

 According to Table 3, in the case of the present invention, in which the punching was performed under lubrication, no cracks were generated on the surface of the steel pipe after processing, good surface quality was obtained, and dimensional accuracy was remarkably good. Was. On the other hand, in Comparative Example 1 in which punching was performed without lubrication, the surface of the processed steel pipe had flaws. In Comparative Example 2 in which the cold drawing method was used under lubrication, the dimensional accuracy was reduced. In Comparative Example 3, which was processed by the lorry forging indentation method under lubrication, the dimensional accuracy was further reduced.

 In this embodiment, a case of so-called double-sided lubrication in which a lubricating film is formed on both the inner and outer surfaces of the pipe is shown. However, the present invention is not limited to this, and a lubricating film is formed on either the inner surface or the outer surface. The so-called one-sided lubrication is also eroded, and it is clear that even with this one-sided lubrication, it is possible to effectively prevent the generation of flaws on the surface on which the lubricating film is formed.

Example 4

 [Honkiaki example]

A steel pipe of 40πΐπι X 6.0 mm t X 5.5 mL was used as a base tube, and this base tube was subjected to the present invention (punching using a plug that can be expanded and reduced in diameter) as outlined in Fig. 1. The pipe was expanded and then reduced in diameter. The target thickness on the die exit side was 6.0 nrat, the same as the entry side. The plug was mirror-finished and floated in the tube. The die used was an integrated fixed die with a mirror-finished inner surface of the die hole. Plug expansion ratio, diameter reduction ratio, taper angle between expanded and reduced diameter parts 0 A and β Β, The target outer diameter D2 of the pipe on the die exit side (after diameter reduction) was set to the value shown in Table 4 for each example. The tubes were fed continuously to the dies.

 [Comparative Example A]

 The raw pipe was reduced in diameter by the cold drawing method shown in Fig. 2 (only diameter reduction is possible). The target thickness on the die exit side was 6.0 mm t, the same as that on the entrance side. The plug was mirror-finished and floated in the tube. As the die, an integrated fixed die having a mirror-finished inner surface of the die hole was used. The plug diameter reduction rate and the target outer diameter of the tube on the die exit side were set to the values shown in Table 4 for each example. The tubes were fed continuously to the dies.

 [Comparative example B]

 The pipe was reduced in diameter by the rotary forging indentation method shown in Fig. 3 (only diameter reduction is possible). The target thickness on the die exit side was 6.0 mm t, the same as the entrance side. The plug was mirror-finished and floated in the tube. The die used was a split die with a mirror-finished inner surface of the die hole. The diameter reduction ratio of the plug and the target outer diameter of the tube on the die exit side were set to the values shown in Table 4 for each example. The tubes were fed continuously to the dies.

 Dimensional accuracy (outer diameter deviation, inner diameter deviation, wall thickness deviation) was measured for steel pipes manufactured under the conditions of each of these examples. The outer diameter deviation and inner diameter deviation are calculated by analyzing the cross-section of the pipe in the circumferential direction and calculating the maximum deviation from the perfect circle (that is, (maximum diameter-minimum diameter) Z perfect circular diameter X 100) in the circumferential direction. Determined by The wall thickness deviation is obtained by analyzing the cross-section of the pipe in the circumferential direction and calculating the maximum deviation from the image of the wall cross section with respect to the average wall thickness (that is, (maximum wall thickness-minimum wall thickness) ) Was measured directly. Also, the cross-sectional hardness was measured as an index of the working degree. In addition, the average outer diameter and average wall thickness of the processed pipe obtained at the same time as the above measurement of the dimensional accuracy were employed as indices for determining whether or not a pipe of a certain size was obtained after the processing. Table 4 shows the results.

Table 4 shows that all of the examples of the present invention have remarkably good dimensional accuracy after processing, and that by changing the combination of plug and die, the raw pipes of the same size have a constant size and different powers. A tube was obtained. On the other hand, in the comparative example, the dimensional accuracy was reduced, and it was not possible to obtain a constant-sized outer diameter or wall thickness when trying to obtain pipes having different working degrees from the same size Hata pipe. In the example of the present invention satisfying one or both of 0 A <0 B and D 2 <D 0, the floating state of the plug in the pipe was further stabilized. The expansion ratio a (%) = (D 1 -D 0) / D 1 X100

 Diameter reduction b (%) = (D 1 -D 2) ZD 1 X100

 Example 5

 (Examples 5.1 to 5.4 of the present invention)

 Using a stainless steel tube with an outer diameter of 40 mm and a wall thickness of 6 mm, the punching process shown in Fig. 1 was tried using a mirror-surfaced plug and an integrated fixed die. Shape condition of plug die used

Table 5 shows (plug angle, diameter of plug, length of plug pairing, and die angle). The plug was floated in the tube. The wall thickness of the tube on the die exit side was set to 5 mm.

 (Comparative Example 5.1-5.4)

 A steel pipe with the same lot as the example of the present invention was used as a raw tube, and the shape conditions of the plug and die used were different as shown in Table 5, and other than the above, the punching process was tried in the same manner as the example of the present invention. did.

 (Conventional example 5.1)

 The steel pipe having the same mouth as the example of the present invention was used as the raw pipe, and the processing by the cold drawing method shown in FIG. 2 was tried by using the mirror plug and the integral fixed die. Table 5 shows the plug and die shape conditions used. The plug was floated in the tube. The wall thickness of the tube on the die exit side was set to 5 ra ni.

 (Conventional example 5.2)

 Using a steel tube of the same lot as the example of the present invention as a raw tube, processing using the rotary forging indentation method shown in Figs. 3A and 3B was attempted using a single-face tally forging machine equipped with a mirror plug and a split die. . Table 5 shows the shape conditions of the plug die used. The plug was floated in the tube. The thickness of the tube on the die exit side was increased to 7 mm.

 Table 5 shows the dimensional accuracy (wall thickness deviation, 內 diameter deviation, outer diameter deviation) measured for the product pipes that could be manufactured by the method of each of the above examples, and the product pipes that could be manufactured. Here, outer diameter deviation and inner diameter deviation are calculated by analyzing the cross-section in the circumferential direction of the pipe and calculating the maximum deviation from a perfect circle (ie, (maximum diameter-minimum diameter) Z perfect circle diameter X100%) in the circumferential direction. It was determined by calculation. The wall thickness deviation is obtained by analyzing the cross-section of the pipe in the circumferential direction and analyzing the wall thickness section from the image of the wall thickness to the maximum deviation from the average wall thickness (that is, (maximum wall thickness-minimum wall thickness) Z average wall thickness X100% ) Was measured directly.

From Table 5, it can be seen that in the present invention example, the punching process can be completed stably, and the dimensional accuracy of the product pipe is It was remarkably good. On the other hand, in all of the comparative examples, the punching process could not be completed, and no product pipe was obtained. In the conventional example, the processing was completed, but the dimensional accuracy of the product tube was reduced.

Example 6

 (Example 6.1)

 Using a steel pipe of φ4 OmmX 6 mm t X 5.5 mL, YS 400 MPa as a raw tube, trial production of a high dimensional precision tube by punching with the diameter reduction ratio set to 13% in the configuration shown in Fig. 10 did. Angle 21 early in production. And a plug having an angle of 21 ° and a taper length of 1 lmm were used. The plug was floated in the tube. The lubricant was applied to each tube before processing by immersing the tube in the lubricant in the coating tank. A fast-drying solvent-diluted polymer lubricant was used as the lubricant.

 During the processing, the load in the punching direction was constantly measured by the above-described measuring method, and the punching was performed while comparing the measured load with the calculated load calculated by the above formula 4. In Equation 4 in this example, as the values of a and n, a = 0.001 85 and n = 1 which are optimal values derived by conducting experiments in advance (when the pipe end state is free to rotate) ) Was used. Since the measured load exceeded the calculated load during the machining of the multiple tubes, machining was interrupted and the machining was interrupted. The machining conditions were changed as follows. That is, dice the angle to 1 1. Replace the plug and the plug at an angle of 1 1. The taper length was changed to 2 Omm. Processing was resumed after this replacement, and the processing of the remaining multiple pipes was completed without difficulty.

 When resuming the above-mentioned exchange, processing is performed by cutting and separating the die entry side and die exit side of the pipe being processed in the previously used die, and the previously used plug is mounted. After removing the previously used dice from the specified mounting position with the inner part of the die of the inserted tube in the same position, attach the next used die to the specified mounting position, and use the same size and size for the next processing. Processing was resumed by inserting a plug for later use into the YS tube. Further, the die exit side portion of the separated pipe could be adopted as a product. The die entry side of the pipe was scrap.

 (Comparative Example 6.1)

Using the same steel pipe as in Example 6.1 as a raw pipe, production of a high-dimensional precision pipe was tried by punching with the diameter reduction ratio set to 13% in the form shown in FIG. Angle 2 1 early in manufacturing. Dice and the angle 2 1. A plug having a taper length of 2 Oram was used. Plug in tube Floating. The lubricant was applied to each tube before processing by dipping the tube in the lubricant in the coating tank. As the lubricant, a fast-drying solvent-diluted polymer lubricant was used. During processing, the load in the punching direction was not measured, and the condition change in the event of an abnormality was left to the operator's discretion.

 Since the dies broke during the processing of the multiple tubes, the processing was interrupted, the dies and plugs were replaced with the same ones as the initial one, and the lubricant in the lubricant coating tank was changed to a faster one with a higher molecular weight. After replacing the solvent with a dry solvent-diluted polymer lubricant, and then restarting the processing, the die was cracked during the processing of multiple pipes from the restart. Therefore, the machining was interrupted and the machining conditions were changed as follows. That is, dice the angle 1 1. Replace the plug and set the angle to 1 1. The taper length was changed to 2 O mm. Processing was resumed after this replacement, and processing of the remaining multiple pipes was completed without difficulty.

 (Comparative Example 6.2)

 Using the same steel pipe as in Example 6.1 as a raw pipe, production of a high-dimensional precision pipe was attempted by drawing with a diameter reduction ratio of 13%. Initially, a 21 ° angle die and a plug with an angle of 21 ° and a tape length of 2 O mm were used. The plug was floated in the tube. In addition to the bond processing and the application of metal stone は, the required pipe piercing (not necessary for punching) was performed for drawing.

 During processing, the load in the pull-out direction was not measured, and conditions were changed at the time of abnormality, and this was left to the discretion of the operator.

 Since the dies broke during the machining of the multiple tubes, machining was interrupted and the machining conditions were changed as follows. That is, dice the angle 1 1. And the plug was changed to an angle of 11 ° and a taper length of 2 Om m. Processing was resumed after this exchange, and processing of the remaining multiple pipes was completed without difficulty.

Table 6 shows the change conditions during processing, the relative processing time, and the loss during processing for the examples and comparative examples, together with the results of investigations on the dimensional accuracy of the products. The relative machining time is shown as a value obtained by dividing the time required for machining in each case (total machining time Z total number of machining pieces) by that of Comparative Example 1. The dimensional accuracy was indicated by the thickness deviation and the outer diameter deviation. These deviations were calculated from the data obtained by analyzing the cross-section of the pipe in the circumferential direction. The thickness deviation was calculated as a value for the average wall thickness, and the outer diameter deviation was calculated as a value for a perfect circle (target outer diameter). As is clear from Table 6, the present invention was able to stably and efficiently manufacture a dimensional accuracy tube.

Example 7

 Hereinafter, the present invention will be described more specifically with reference to examples.

 The apparatus of Example 7.1 is a plug 1 having an entrance end diameter MD, a central part diameter of 30 tongues, and an exit end diameter of 28 min with a mirror-finished surface to be brought into contact with the inner surface of the pipe, and an integrated fixed die, which It is composed of a die 2 with a hole diameter 40πιηι with a mirror-finished surface and a hydraulic cylinder, and can be operated in either the "continuous pushing" or "intermittent pushing" operation mode, and applies a pushing force to the pipe in the set operation mode. As shown in Fig. 1, plug 1 is a fixed plug whose one end is fixed and inserted into the pipe, and the operation mode of pipe press 3 is "intermittent pressing". Set to. Using this apparatus, a carbon steel pipe having an outer diameter of 40 mm and a thickness of 6 nmi was punched out to obtain a product pipe having an outer diameter of 38 strokes and a thickness of 6 mm.

 In Example 7.2, a carbon steel pipe having an outer diameter of 40 mn and a thickness of 6 mm was punched out in the same manner as in Example 7.1 except that the plug 1 was replaced with a fixed plug and a floating plug was used. A product tube having an outer diameter of 38 inm and a wall thickness of 6 mm was obtained.

 Example 7.3 is the same as Example 7.2 except that the setting of the operation mode of the pipe pushing machine 3 is changed from “intermittent pressing” to “continuous pressing”. A carbon steel pipe of mm was punched out to obtain a product pipe with an outer diameter of 38 mm and a wall thickness of 6 mm.

 Also, as Comparative Example 1, a plug 5 having an inlet end diameter of 28 mm, a central portion diameter of 28 mm, and an outlet end diameter of 26 nmi having a mirror-finished surface to be brought into contact with the inner surface of the tube, and an integrated fixed die having a mirror-finished inner surface of the hole As shown in Fig. 2, a die 6 with a hole exit diameter of 38 mm and a pipe drawing machine 7 composed of a hydraulic cylinder, which can be operated by "intermittent drawing" and applies a pulling force to the pipe in a set operation mode as shown in Fig. 2 The device combined with was constructed. Plug 5 was a fixed plug that was fixed in one end and inserted into the pipe. Using this apparatus, a carbon steel pipe with an outer diameter of 40 mm and a wall thickness of 7 mm was drawn out to obtain a product pipe with an outer diameter of S8imX and a wall thickness of 6 hires. In Comparative Example 1, it took time to pull the steel pipe tip and pass it through the die hole.

Also, as Comparative Example 2, in Example 7.1, the same plug 5 as in Comparative Example 1 was used instead of plug 1, and the split die 9 (the outlet of this) was incorporated into rotary forging machine 8 instead of die 2. The inner diameter of the side is the same as the diameter of the hole exit of the die 2.) The outer diameter is 40 nm. 38 positions A product tube with X thickness of 6ωη was obtained.

 Table 7 shows the results of measuring the dimensional accuracy of these product tubes. The method of measuring the deviation of the wall thickness, inner diameter, and outer diameter in the circumferential direction shown in Table 7 is as follows.

 The outer diameter (or inner diameter) deviation is defined as the maximum deviation from the true circle from the circumferential distribution data of the outer diameter (or inner diameter) measured by rotating the tube with the micrometer in contact with the outer (or inner) surface of the tube. Calculated. The circumferential thickness deviation was directly measured from the image of the thickness section as the maximum deviation from the target thickness. Note that the outer diameter deviation and the inner diameter deviation may be calculated from the circumferential distribution data of the distance between the tube and the laser oscillation source measured by irradiating a laser beam, instead of contacting the micrometer. Further, the circumferential thickness deviation may be calculated as a difference between the circumferential diameter distribution data of the outer diameter and the circumferential diameter distribution data of the above diameter.

 The wall thickness deviation (circumferential wall thickness deviation), 內 diameter deviation, and outer diameter deviation are defined as follows. Wall thickness deviation = (maximum wall thickness-minimum wall thickness) Z target wall thickness (or average wall thickness) X100 (%) Bore deviation-(max. Diameter deviation-(maximum outer diameter-minimum outer diameter) / Target outer diameter (or average outer diameter) X100 (%) From Table 7, it is found that the product pipes of the devices of Examples 7.1 to 7.3 have extremely high dimensional accuracy. Good, especially when floating (Example 7.2), and a product tube with high dimensional accuracy was obtained even after continuous punching (Example 7.3). On the other hand, the dimensional accuracy of the product pipe was reduced by the conventional drawing (Comparative Example 7.1). The dimensional accuracy of the product tube was reduced even by pushing with a rotary forging machine (Comparative Example 7.2).

Example 8

 (Example 8.1 of the present invention)

φ4 OmmX 6 mm t X 5.5 mL steel pipe was used as the material, and as shown in Fig. 11, a plurality of dies 2 corresponding to the product dimensions of each pipe were previously placed on the die turntable 19 in the order of pipe processing. , 20, 1, and 20 are assembled, and then a die 2 corresponding to the product dimensions of the front pipe 4 is arranged in the pass line, and the front pipe 4 is pressed into the die 2 by the indenter 2 to perform punching. After finishing, the die turntable 19 is rotated to feed a plurality of dies in order.Instead of the die 2, a die 20 corresponding to the outer diameter of the product of the next pipe 7 is arranged in the pass line. Before the die 20 was placed in the pass line, the plug 22 was inserted into the next pipe 5, and subsequently, the next pipe 7 was pressed into the die 20 by the indenter 2 to perform punching. By repeating this process, high dimensional precision tubes of various product dimensions were manufactured. (Example 8.2 of the present invention)

 φ4 OmmX 6mm tX 5.5 mL steel pipe was used as the material, and as shown in Fig. 12, a plurality of dies 2, 3 corresponding to the product dimensions of each 20, 20 ', and then arrange the dies 2 according to the product dimensions of the front tube 4 in the pass line, and press the front tube 4 into the die 2 with the pushing machine 2 to perform the punching process. After the completion, the die straightening table 23 was moved straight forward to feed a plurality of dies, and instead of the dies 2, the dies 20 corresponding to the outer diameter of the product of the next pipe 7 were arranged in the pass line. At this time, the plug 22 was inserted into the next pipe 5 before the die 20 was placed in the pass line. Subsequently, the next pipe 7 was pushed into the die 20 by the pushing machine 2 to perform punching. By repeating this process, high-precision tubes of various product dimensions were manufactured.

 (Comparative Example 8.1)

 4 OmmX 6mm tX 5.5mL steel pipe was used as the raw material, and a plurality of dies with different hole types were prepared and punched out as shown in Fig.13. The die 2 to be used first was placed in the pass line, and the front pipe 4 was first pushed into the die 2 by the pushing machine 3 to complete the punching process. Next, instead of the die 2, the die 20 corresponding to the outer diameter of the product of the next pipe 7 was manually arranged in the pass line. At this time, the plug 22 was inserted into the next pipe 7 in the pass line before the die 20 was placed in the pass line. Then, the next pipe 7 was pushed into the die 20 by the pushing machine 2 to perform a punching process. By repeating this process, high-precision tubes with various product dimensions were manufactured.

 (Comparative Example 8.2)

 4 OmmX 6mm tX 5.5 mL steel pipe was used as the raw material, and a plurality of different-hole dies were prepared and pulled out as shown in Fig. 13. The die 2 to be used first was placed in the pass line, and first, the front pipe 4 was pushed into the die 2 by the pushing machine 2 to complete the punching process. Next, instead of the die 2, the die 20 corresponding to the outer diameter of the product of the next pipe 7 was manually arranged in the pass line. At this time, the next pipe 7 was once moved out of the pass line, plug 22 was inserted, and then returned into the pass line. Then, the next pipe 7 was pushed into the die 20 by the pushing machine 2 to perform a punching process. By repeating this process, high-precision tubes with various product dimensions were manufactured.

Table 8 shows the processing efficiency and the dimensional accuracy of the product in the inventive examples and comparative examples. Machining efficiency was evaluated by the number of steel pipes punched out per unit working time.Table 8 shows the machining efficiency of Comparative Example 2. The efficiency is shown as a relative value assuming that it is 1. The dimensional accuracy was indicated by the thickness deviation and the outer diameter deviation. These deviations were calculated from the data obtained by image analysis of the circumferential section of the pipe. The thickness deviation was calculated as a value for the average thickness, and the outer diameter deviation was calculated as a value for a perfect circle (target outer diameter).

 As is clear from Table 8, the present invention significantly improved the punching efficiency.

Example 9

 Hereinafter, the present invention will be described in more detail with reference to Examples.

 (Example 9.1)

 As shown in FIG. 14, a pipe bending fine-adjustment means 24 was installed immediately near the exit side of the die 2. Although not shown in the figure, a reciprocating gun pusher was installed on the dice 2 entry side, which continuously pushed the die 4 into the dice 2 with the tube 4 interposed between endless tracks.

 As shown in FIG. 15, the pipe bending fine-adjustment means 24 supports a hole type 26 having a hole 27 through which the pipe passes by a support substrate 28 so as to be movable in a plane orthogonal to the pipe passing direction. Then, the hole type moving mechanism 29 supported by the supporting substrate 28 is used to move one or more of the four points on the outer periphery of the hole type 26 in a direction perpendicular to the pipe passing direction (hole type movement). In the direction 3 3), the pressing force is adjusted by screwing a wedge-shaped mold 30 with a tapered surface in contact with the outer periphery of the bore 26 as shown in Fig. 16. It was provided by moving it in the pipe direction 25 with the screw 31. In FIG. 16, when the adjustment screw 31 is turned clockwise, the wedge-shaped die 30 rises, and the hole die 26 in contact with the tapered surface moves leftward. After the fine adjustment of the hole shape position, the fixing screw 32 is tightened to fix the hole shape 26 to the support substrate 28.

 Using this device, a steel pipe of φ4 O mm X 6 mm t X 5.5 r L is used as a material, and this material is continuously fed while a plug 1 is inserted into the pipe and floating, and a die 2 is formed. An attempt was made to manufacture a high-precision pipe by punching into a hole. The steel pipe after the punching process passed through the hole 27 of the die 26 near the die 2 exit side. The hole 27 of the hole type 26 is a straight hole, and the hole diameter is set to be 0.5 mm larger than the exit hole diameter of the die 2 (φ35 mm in this example).

Before the actual production trial, a plurality of dummy tubes were used, and the bending of the tube was measured by performing a punching experiment with several different hole positions, and the variation in the hole position and the bending of the tube after punching were measured. The relationship with variation was sought. During the actual production trial, when the bend of the pipe is about to exceed a predetermined threshold, fine adjustment of the position of the hole is performed by moving the hole in the direction in which the bend becomes smaller based on the relationship. Was. (Example 9.2)

 As shown in Fig. 17, the pipe bend fine adjustment means 24 is installed near the exit side of the die 2, and the guide cylinder 35 is installed immediately near the entry side of the die 2, and the pipe bend fine adjustment means 24 is installed. A guide cylinder 36 was installed immediately near the exit side. Although not shown in the figure, a continuous pushing machine was installed on the entry side of the entry side guide cylinder 3 5, in which the tube 4 was sandwiched between endless tracks and fired with a gun and pushed into the die 2.

 As shown in FIG. 18, the pipe bending fine-adjustment means 24 supports a hole type 26 having a hole 27 through which the pipe passes so as to be movable on a support substrate 28 in a plane orthogonal to the pipe passing direction. Then, the hole type moving mechanism 29 supported by the supporting substrate 28 is used to move one or more of the four points on the outer periphery of the hole type 26 in a direction perpendicular to the pipe passing direction (hole type movement). A method of pushing or pulling in the direction 3 3) was adopted, and the pushing or pulling force was applied by a small hydraulic cylinder 34 in contact with the outer periphery of the hole 26. By adjusting the pressure difference between the two hydraulic cylinders 34 facing each other in FIG. 18, the bore 26 moves in the direction facing the two hydraulic cylinders 34. After the fine adjustment of the hole position, the pressure difference between the opposing hydraulic cylinders 34 is reduced to zero, and the hole 26 is fixed to the support substrate 28.

 Using this device, a steel pipe of Φ 4 O mm X 6 mm t X 5.5 mL is used as a material, and this material is fed by a continuous gun while floating by inserting a plug 1 into the pipe. An attempt was made to manufacture a high-precision pipe by punching into die 2. The steel pipe before the punching worked penetrated through the inlet side guide cylinder 35, and the steel pipe after the punching worked through the hole 27 of the die 26 near the die 2 outlet side and the outlet side guide cylinder 36 in order. The hole 27 of the hole type 26 is a tapered hole, and the diameter of the largest diameter portion (located on the inlet side) is 2.5 mm compared to the exit hole diameter of the die 2 (φ33 mm in this example). I took it big. The hole diameter of the minimum inner diameter portion (located on the outlet side) of the hole mold 26 was the same as the outlet hole diameter of the die 2. In addition, the inlet and outlet side guide cylinders 35 and 36 have inner diameters that are 0.5 mm larger than the outer diameter of the same side pipe so that the pipes are not damaged. Before the actual production trial, multiple dummy pipes were used, and the bending of the pipe was measured by performing a punching experiment with several different hole positions, and the variation in the hole position and the bending of the pipe after punching were measured. The relationship with the variation was determined. During the actual production trial, when the bend of the pipe is about to exceed a predetermined threshold, fine adjustment of the position of the hole is performed by moving the hole to the direction in which the bend becomes smaller based on the above relationship. Was.

 (Comparative Example 9.1.1)

As shown in Fig. 19, a guide cylinder 35 is installed near the entrance side of the die 2, and The guide cylinder 36 was installed. Although not shown in the figure, a continuous indenter was installed on the entrance side of the entrance side guide cylinder 35, in which the pipe 4 was continuously inserted into the die 2 with the tube 4 sandwiched by an infinite path.

 '' Using this device, a φ4 O mm X 6 mm t X 5.5 mL steel pipe is used as a material. 2 (in this example, the exit hole diameter was 33 mm). The steel pipe before the punching worked penetrated the inlet guide cylinder 35, and the steel pipe after the punching worked penetrated the outlet guide cylinder 36.

 (Comparative Example 9.2)

 As shown in FIG. 20, nothing was installed near the entrance and the exit of the die 2. Although not shown, a continuous indenter was installed on the dice 2 inlet side, in which the pipe 4 was intermittently inserted into the endless track and pushed into the dice 2.

 Using this device, a steel pipe of Φ 4 O mm X 6 mmt X 5.5 mL is used as the material, and this material is continuously fed while the plug 1 is inserted into the pipe and floating, and the die 2 (this In the example, we tried to manufacture a high dimensional accuracy pipe by punching into the outlet hole diameter * 35 mm).

 (Comparative Example 9.3)

 As shown in FIG. 21, nothing was installed near the entrance and the exit of the die 2. No pusher was installed on the die 2 inlet side, and a puller 37 was installed on the die 2 outlet side. Using this device, a steel pipe of Φ4 O mm X 6 mm t X 5.5 mL is used as a material, and this material is floated by inserting a plug 1 into the tube, and a drawing machine 37 is used to draw the material. An attempt was made to produce a high dimensional precision pipe by drawing the steel pipe from the die 2 (in this example, the exit hole diameter is 35 mm) in the drawing direction 38 while holding the tip.

 Table 9 shows the results of investigating the bending and dimensional accuracy of the pipes manufactured by the methods of the above examples and comparative examples. The bending of the pipe was evaluated by applying a straight line ruler to the pipe, and the maximum value of the gap between the pipe and the straight ruler at the center of the pipe per 50 O mm in length. The dimensional accuracy of the pipe was indicated by the wall thickness deviation and the outer diameter deviation (the maximum value of the data of multiple pipes manufactured in each case). These deviations were obtained from the data obtained by image analysis of the circumferential cross section of the pipe. The wall thickness deviation was calculated as a value for the average wall thickness, and the outer diameter deviation was calculated as a value for a perfect circle (target outer diameter).

As is clear from Table 9, it was possible to sufficiently prevent bending of the pipe after punching while obtaining extremely good dimensional accuracy according to the present invention. Example 10

 As an embodiment of the present invention, an equipment row as shown in FIG. 22 was configured. 3 9 is a punching device. This device performs a punching process by inserting a plug 1 into a tube and floating the tube while continuously pushing the tube into a die 2 with a pressing device 4 3. The punching device 39 is provided with a die exchanging device 45, a plug exchanging device 44, and a bending preventing device 46, which are configured as described above, as preferred embodiments.

 On the entry side of the punching device 39, a pipe end surface grinding device 40, a lubricant immersion coating tank 41, and a drying device 42 are arranged in this order from the upstream side. The pipe end surface grinding device 40 is configured to be capable of right-angle grinding in which the end surfaces of pipes arranged on a table are cut at right angles in the pipe axis direction with a grinding tool. The lubricant immersion coating tank 41 stores a drying liquid lubricant emulsion, and the pipe is immersed in the emulsion bath to apply the lubricant to the pipe. The drying device 42 is configured to be able to dry the tubes arranged on the table after the application of the lubricant by blowing hot air. At the entry side of this equipment row, there is provided a tube holder 47 that receives the raw tube sent from the previous process and passes it to the tube end surface grinding device 40, and at the exit side it is stamped. A pipe dispensing stand 48 for dispensing pipes that have become product pipes to subsequent processes is provided.

 Using this equipment row, the element with the oxide scale adhered has various dimensions in the range of outer diameter of 25 to 12 O mm φ, wall thickness of 2 to 8 mm, and length of 5 to 13 m. The pipe was subjected to a pipe end perpendicularity process, dip coating with lubricant, drying, and punching to obtain a product pipe.

 On the other hand, Fig. 23 shows a row of manufacturing equipment by conventional drawing as a comparative example. In this equipment line, a pipe receiving stand 47 is provided on the inlet side of the drawing apparatus 50, and a tube tapping table 48 is provided on the outlet side. The drawing apparatus 50 is equipped with a plug 1 on the side. The pipe is drawn out of the die 2 by the drawing apparatus 50 while being inserted and floated. In addition, a plug changing device S44 and a die changing device 45 configured in the same manner as in the example were provided in the drawing device 50. In this equipment row, the same scaled pipe as in the example cannot be pulled out as it is, and the pipe that has passed through the first pretreatment step shown in Fig. 23 and the second pretreatment step next to it is drawn out. Must be a tube.

The first pretreatment step is indispensable as a means for forming a strong lubricating film for the drawing process, and cuts a scaled Hata pipe into a short length → removes the scale by pickling → neutralizes the acid with a strong force → Washing → Bond treatment Applying metal stone 鹼 → Drying consists of many sequential steps. The plurality of immersion tanks or apparatuses for performing the first pretreatment step are the same as the drawing apparatus 50. 配備 Deployed on the line, the productivity is reduced. In addition, the second pretreatment step is indispensable as a means for causing the drawing apparatus 50 to hold the pipe, for example, as a means for forming a pipe tip using a rotary forging machine. If it is deployed on the same line as the device 50, productivity will drop, so it is deployed on a separate line.

 Using the equipment row of this comparative example, the same scaled tube as in the example was subjected to the drawing process on the pre-processed tubes that were sequentially processed in the first and second pre-processing steps to obtain product tubes. .

 Table 10 shows the time required for production and the dimensional accuracy of the product tubes examined for the examples and comparative examples. The required manufacturing time is evaluated by the total processing time / total number of processed pipes from a given lot of scaled Hata pipes to product pipes.Table 10 shows the evaluation value of the comparative example as 1 and the relative ratio to that. Indicated. The dimensional accuracy was indicated by the thickness deviation and the outer diameter deviation. These deviations were obtained from data obtained by image analysis of the circumferential cross section of the pipe. The wall thickness deviation was calculated as a value for the average wall thickness, and the outer diameter deviation was calculated as a value for a perfect circle (target outer diameter).

 As is evident from Table 10, the present invention was able to efficiently produce a high dimensional accuracy tube. Industrial applicability

The high dimensional accuracy pipe of the present invention has remarkably good dimensional accuracy and as a result has good fatigue strength, and can be manufactured at low cost. It has an excellent effect of contributing to Also, according to the manufacturing method of the present invention, a wide range of required pipe sizes! : It has an excellent effect that a metal pipe with extremely good dimensional accuracy can be manufactured at low cost.

table 1

* Eyes

Table 2

 Machining method Outer wall thickness Outer diameter deviation 內 Diameter deviation Circumferential direction Machining efficiency:

 Thickness deviation Number of pieces that can be machined per hour (%) (%) (%) (pieces) Example of the present invention Same as the punching-in side 0.50 0.5 0.5 0.5 \ 130 Comparative example 2.1 Pulling out Thinning 4. 0 4. 6 5. 0 40 Comparative example 2.2 Rotary single forging push Thickening 3. 8 4. 0 4. 560

Including

Table 3 Processing method Lubricating film Lubricant Thickness deviation of flaw occurrence 內 Diameter deviation Outer diameter deviation Existence Existence (%) (%) (%) Comparative example 3.1 Punching A, Intangible lubricant Yes 2.0 0.21 0.5 Example of the present invention 3.1 Punching out Liquid lubricant not used 0.5 0.5.0.5 0.5 Example of the present invention 3.2 Punching out No grease type lubricant None 0.5 0.5.0.5 0.5 Example of the present invention 3.3 Pressing out Yes Drying resin None 0.3 0.3 0.3 Example of the present invention 3.4 Punching out Solvent diluting solution of drying resin c, 0.3 0.3 0.3 0.3 Invention example 3.5 Punching out Drying resin Emarjo, 0.3 0.3 0.3 0.3 Comparative example 3.2 Extraction with liquid lubricant / ,, 4.5 3.5 3.5 Comparative example 3.3 Press-in-With liquid lubricant None 4.5 4.0 3.5

* Rotary forging indentation method

Table 4

 :-

* ² : Target outer diameter of the tube on the die exit side

Plug and die shape conditions Dimensional accuracy

 Machining method Plug diameter reduction Plug diameter reduction Plug bear Die angle Manufacturable Thickness deviation Inner diameter deviation Outer diameter deviation Part angle Part length Ring part length No

(°) (mm) Sa (mm) (.) (%) (%) (%) Example of the present invention 5.1 Pressing 21 1 1 20 2 1 Possible 0.50, 5 0.5 Example of the present invention 5.2 Pressing 1 1 20 1 5 1 3 Permissible 0.5 0.5 0.5 0, 5 Example of the present invention 5.3 Punching 5 90 4 5 Permissible 0.8.0.8 0.8 0.7 Example of the present invention 5.4 Punching 40 5 35 40 Permissible 0. 3 0.4 0.4 0.3 Comparative example 5.1 Stamping 4 1 1 4 4.5 No-1 Comparative example 5.2 Stamping 45 1 1 2 10 45 No-1-Comparative example 5.3 Stamping 2 1 4 4. 5 2 1 No-1 Comparative Example 5.4 Pressing 5 105 210 5 No-1 Conventional 5.1 Drawing 2 1 1 1 20 2 1 Possible 4.5 5 3.5 3.5 Conventional 5.2 Rotary forging 2 1 1 1 20 2 1 OK 4.5 5 4.0 3.5 Insertion

Table 6

Table 7 Machining mode Die plug Outer wall thickness Circumferential direction Inner diameter deviation Outer diameter deviation Thickness deviation

(%) (%) (%) Example 7.1 Punching (Intermittent) —Fixed Body Type Fixed Equivalent to entry side 0.5 0.5.0.5 0.5 Example 7.2 Punching (Intermittent) Integrated Type Fixed Floating Equivalent to entry side 0.4 0.4 0.5 0.3 Example 7.3 Punching (Continuous)-Body fixed Floating Equivalent to the entry side 0.3 0.3 0.3 0.3 Comparative example 7.1 Pulling (Continuous)-Body fixed Fixed Thinning 5.0 4. 0 4.0 Comparative Example 7.2 Pressing (Intermittent) Split Type p Tally Fixed Thickening 4. 5 4.0 3.5

Table 8

 Machining efficiency Thickness deviation (%) Outer diameter deviation (%) Example of the present invention 8.1 10 0.5 .5 Example of the present invention 8.2 10 0.5 .5 0.5 Comparative example 8.1 1.2 0.8 .0.7 Comparative example 8.2 1 0.8 0.8 0.7

Table 9

Table 10

 Processing method Production time Wall thickness deviation (%) Outer diameter deviation

 (Relative ratio) (%) Example Pressing 0.1 0.5 0.6 Comparative Example Pulling 1 3.5 3.2

Claims

The scope of the claims 1. Any one of outer diameter deviation, inner diameter deviation, and circumferential wall thickness deviation manufactured by punching a metal tube by inserting it into the die and pushing it through the hole of the die with the plug inserted into the tube. Highly dimensionally as-punched tubing characterized by one or more than 3.0%. 2. The metal tube is pushed into the hole of the die with the plug inserted into the tube, and the metal tube is pressed and passed, and the thickness of the metal tube on the exit side of the die is made smaller than that of the entrance side. 2. The as-punched height according to claim 1, wherein one or more of the manufactured outer diameter deviation, inner diameter deviation, and circumferential thickness deviation are not more than 3.0%. Dimensional precision tube. 3. The high dimensional accuracy according to claim 1, wherein the punching is performed while the metal pipe is circumscribed around the plug and circumscribed around the die within the same cross section of the pipe. tube. 4. The high dimensional precision tube according to any one of claims 1 to 3, wherein the die is an integrated die and / or a fixed die. 5. A method for manufacturing a high dimensional precision tube, comprising: pressing a metal tube into a hole of a die while inserting a plug into the tube, thereby performing punching. 6. The method according to claim 5, wherein the thickness of the pipe on the exit side of the die is equal to or less than the thickness of the pipe on the entry side. 7. The high dimensional accuracy according to claim 5, wherein the punching is performed while the metal pipe is circumscribed around the plug and the die is circumscribed in the same cross section of the pipe. Pipe manufacturing method. 8. The method according to claim 5, wherein the die is an integrated die, a Z die or a fixed die. 9. The method according to any one of claims 5 to 8, wherein the plug is a floating plug. 10. In claim 5, when improving one or more of the outer diameter deviation, the inner diameter deviation, and the thickness deviation in the circumferential direction of the pipe by the punching process to obtain a high dimensional accuracy pipe, A high-efficiency manufacturing method for high-dimensional precision pipes, characterized in that pipes are continuously fed into a die (2) by means of a pipe feeding means on the die entry side while a plug is inserted and floated. 11. The method according to claim 10, wherein the pipe feeding means is a jar for gripping a pipe before processing.  12. The method according to claim 10, wherein the pipe feeding means is an endless belt for holding the pipe before processing. 13. The method according to claim 10, wherein the pipe feeding means is an intermittent feeder for intermittently feeding a pipe before processing by alternately gripping the pipe before processing. 14. The method according to claim 10, wherein the pipe feeding means is a press for sequentially pressing the pipes before processing. 15. The method according to claim 10, wherein the tube feeding means is a hole-type roll for sandwiching the tube before processing. . 16. The method according to claim 15, wherein the rolls are two or more rolls. . 17. The method according to claim 15, wherein two or more stands are provided for the rolls. 16 High-efficiency manufacturing method for high-precision pipes described in 6. 18. The high surface quality of claim 5, wherein after forming a lubricating film on the inner surface and / or outer surface of the tube, a plug is inserted into the tube and the tube is punched out with a die. Manufacturing method for dimensional accuracy tubes. 19. The method according to claim 18, wherein the pipe on which the lubricating film is formed is a steel pipe with the oxide scale remaining attached. 20. The method according to claim 18 or 19, wherein the lubricating film is formed using a liquid lubricant. 21. The method according to claim 18 or 19, wherein the lubricating film is formed using a grease-based lubricant. 22. The method according to claim 18 or claim 19, wherein the lubricating film is formed using a dry resin. 23. Applying the drying resin, a liquid obtained by diluting the drying resin with a solvent, or an emulsion of the drying resin to a tube, and then subjecting the tube to hot air or air drying to form the lubricating film. The method for producing a high-dimensional precision tube having good surface quality according to claim 22, characterized in that: 24. The method for manufacturing a high-dimensional precision pipe according to claim 5, wherein pipes of a constant size having different working rates are manufactured with high dimensional accuracy from raw pipes of the same size, wherein the pipe can be expanded and reduced in diameter. A method for producing a high-dimensional precision pipe, comprising inserting a plug into a pipe and punching the pipe with a die. 25. Floating the plug in the tube and continuously supplying the tube to the die 25. The method for producing a high-precision pipe according to claim 24, wherein: 26. The method for manufacturing a high-precision pipe according to claim 24, wherein the plug is a plug having a tapered angle of an expanded portion less than a tapered angle of a reduced diameter portion. 27. The method of manufacturing a dimensional accuracy pipe according to any one of claims 24 to 26, wherein a target outer diameter of a pipe on an outlet side of the die is smaller than an outer diameter of a pipe on an inlet side of the die. Method. 28. In manufacturing a high dimensional accuracy pipe according to claim 5, wherein a pipe having a plug inserted therein is pressed into a hole of a die and passed therethrough, a surface of a diameter reduced as the plug is a processing center. The angle between the axis and the axis is 5 to 40. A plug with a reduced diameter portion of 5 to 10 Omm in length and a die with an angle of 5 to 40 ° between the inner surface of the hole on the inlet side and the processing center axis are used as the die. A stable manufacturing method for high-dimensional precision pipes. 29. The method for stably manufacturing a high dimensional precision tube according to claim 28, wherein the length of the bearing portion of the plug is set to 5 to 20 Omm. 30. The high dimensional precision pipe according to claim 28 or 29, wherein the thickness of the pipe at the exit side of the die is set to be equal to or less than the thickness of the pipe at the entrance side. Stable manufacturing method. 31. The method for stably manufacturing a high-dimensional precision tube according to any one of claims 28 to 30, wherein an integrated fixed die is used as the die. 32. The method for stably manufacturing a high-dimensional precision pipe according to any one of claims 28 to 31, wherein the plug is floated in the pipe. 33. The method for manufacturing a high-precision pipe according to claim 5, wherein the plug is inserted into the pipe and the pipe is floated while the pipe is pushed into a die and passed therethrough. Measure the load in the punching direction, and measure the measured load and the material of the raw pipe as the pipe before processing. High dimensional accuracy characterized by comparing the calculated load calculated from one of the following [Equation 4] to [Equation 6] based on the material characteristics and judging whether or not to continue punching based on the result. Pipe Stability Manufacturing method. Record [Equation 4] _{σ ΐ £ ΧTube} cross-sectional area Here, a _k = YS X (1-a X λ), λ = (L / V "n) / k, a -O. 00 185 to O. 0 1 5 5, L: pipe ft, k ： Secondary radius, kz-

/ l S, n: pipe end condition (n = 0.25 to 4), d ₁ : outer diameter of pipe, d ₂ : inner diameter of pipe, YS: yield strength of pipe (Equation 5) Yield strength of pipe YSX pipe cross-sectional area  (Equation 6) Tensile strength of tube T S X Cross-sectional area of tube 34. If the measured load is less than the calculated load, it is determined that continuation is possible and processing is continued, while if the measured load is greater than the calculated load, it is determined that continuation is not to be performed, and processing is interrupted. 34. The method for stably manufacturing a high-dimensional precision pipe according to claim 33, wherein the processing is restarted after exchanging the die and / or the plug for another shape corresponding to the same product pipe size. 35. The method of claim 34, wherein the dies and / or plugs used after the replacement have smaller dies and / or plug angles than those before the replacement. 36. A lubricant is applied to the raw tube before the punching process, and the type of the lubricant is changed only when the measured load exceeds the calculated load. 35. A method for stably manufacturing a high-precision pipe according to any one of to 35. 37. It has a plug that can contact the entire circumference of the metal pipe, a die with a hole that can be eroded all around the outer surface of the pipe, and a pipe pushing machine that pushes the pipe. An apparatus for manufacturing a high-dimensional precision pipe, characterized in that it is possible to execute a punching operation in which the plug is inserted into the pipe and the pipe is pushed into the hole of the die by the pipe pressing machine. 38. The apparatus according to claim 37, wherein the die is an integrated die, a Z die or a fixed die. 39. The method of claim 37, wherein the plug is a floating plug. 38. A high-precision pipe manufacturing apparatus according to item 8. 40. The apparatus for manufacturing a high-dimensional precision pipe according to any one of claims 37 to 39, wherein the pipe pressing machine continuously presses the pipe. 41. The apparatus for manufacturing a high-precision pipe according to any one of claims 37 to 39, wherein the pipe pushing machine intermittently pushes the pipe. 42. The method for manufacturing a high-precision pipe according to claim 37, wherein a plug is inserted into the pipe to float the pipe, and the pipe is continuously or intermittently pressed into a die and punched out. Different dies are arranged on the same circumference, and one of these dies is moved in the circumferential direction of the arrangement according to the product dimensions, placed in the pass line, and used for punching. Highly efficient manufacturing method of high dimensional accuracy tube. 43. The method for manufacturing a high-precision pipe according to claim 37, wherein the pipe is inserted and floated by inserting a plug into the pipe, and the pipe is continuously or intermittently pressed into a die and punched. Are arranged on the same straight line, and one of these dies is moved in the linear direction of the arrangement according to the product dimensions, placed in the pass line, and used for punching. High-efficiency manufacturing method for high-dimensional precision pipes. 4 4. When changing the product dimensions between the front pipe and the next pipe, after pushing out the front pipe, stop the next pipe at the die entry side, and before and after or during the movement of the die according to the product dimensions of the next pipe. 4. The method of claim 4, wherein a plug corresponding to the dimensions of the product is inserted into the next pipe. 45. In Claim 37, a die for passing a pipe, a pushing machine for pushing a pipe into a die in a pass line, and a plurality of dies are supported in the form of being arranged on the same circumference and are supported in the circumferential direction. A high-precision pipe high-efficiency manufacturing device that has a die turntable that conveys and arranges one of the dies in a pass line. 46. In Claim 37, a die for passing a tube, a pushing machine for pushing a tube into a die in a pass line, and a plurality of dies are supported in a form of being arranged on the same straight line and conveyed in the straight line direction. And a high-precision tube high-efficiency production device having a die straight-running table for arranging one of the dies in a pass line. 47. The method for manufacturing a high-precision pipe according to claim 5, wherein a plug is inserted into the pipe to float the pipe, and the pipe is pressed into a die to perform punching. A method for manufacturing a high-dimensional precision pipe, characterized in that the pipe is prevented from being bent by passing the die outlet side pipe through a hole having a pre-adjusted position in a plane perpendicular to the direction. 48. The method according to claim 47, wherein the pipe on the die entrance side and / or the hole-shaped exit side is passed through a guide cylinder. 49. The method according to claim 47, wherein the tube is continuously pressed into a die. 50. The apparatus for manufacturing a high-precision pipe according to claim 37, further comprising: a die for passing the pipe, and a pushing machine for pushing the pipe into the die, wherein a die for passing the pipe is provided immediately near the die exit side; A fine bend adjusting means having a support substrate movably supporting the die in a plane orthogonal to the pipe direction and a die moving mechanism supported by the support substrate to move the die is provided. A high-precision pipe manufacturing apparatus characterized in that: 5 1. A method in which the hole-type moving mechanism pushes one or more points of the hole-shaped outer peripheral portion through a taper surface of a wedge-shaped mold that moves in the tube-flow direction in a direction perpendicular to the tube-pass direction. That it is The apparatus for manufacturing a high-precision pipe according to claim 50, characterized in that: 52. The apparatus according to claim 51, wherein the movement of the wedge-shaped mold is urged by a screw. 53. The method according to claim 50, wherein the hole-type moving mechanism pushes or pulls one or two or more points of the hole-shaped outer periphery ^ in a direction orthogonal to the direct pipe direction. High dimensional precision tube manufacturing equipment. 54. The apparatus for manufacturing a high-precision pipe according to claim 53, wherein the push or pull of the push or pull method is urged by a fluid pressure cylinder. 55. The apparatus for manufacturing a high-precision pipe according to any one of claims 50 to 54, wherein a hole diameter of the die is equal to or larger than an exit hole diameter of the die. 56. The apparatus for manufacturing a high-dimensional precision tube according to any one of claims 50 to 55, wherein the hole of the hole type is a straight hole or a taped hole. 57. The high dimensional precision tube according to any one of claims 50 to 56, further comprising a guide tube through which the tube on the die entrance side and / or the tube bending fine adjustment unit exit side is passed. manufacturing device. . 58. The apparatus for manufacturing a high-precision pipe according to any one of claims 50 to 57, wherein the pusher is a continuous pusher capable of continuously pushing a pipe. 59. A production line for high-precision pipes having the punching device according to claim 37, wherein the pipe end face grinding device grinds the pipe end face at right angles to the pipe axis direction, and the pipe is lubricated. Manufacturing a high dimensional precision pipe characterized by arranging a lubricant dip coating tank for dipping and applying a lubricant, a drying device for drying a pipe coated with a lubricant, and the stamping device in this order. Equipment row.