JP2013169563A - Ring rolling method - Google Patents

Abstract

Provided is a ring rolling method capable of suppressing generation of internal voids, that is, voids in a ring rolled product.
A main roll 2 and a mandrel 3 of a ring rolling device are divided by an arbitrary plurality of dividing lines 4 with respect to internal voids generated in a ring-shaped product 9 in hot ring rolling, so that these main rolls are divided. 2, the difference in peripheral speed generated between the mandrel 3 and the workpiece 5 is reduced, or the main roll 2 and the mandrel 3 which are divided into a plurality of pieces are lubricated to generate a periphery between the workpiece 5 By making the difference in speed harmless, it is a rolling method comprising a ring rolling process that suppresses the generation of internal voids in the ring-shaped product 9 by the ring rolling process. This is a ring rolling method that performs rolling while rotating the workpiece 5.
[Selection] Figure 8

Description

  The present invention is obtained by reducing the sliding speed at the time of ring rolling in the ring rolling method, thereby suppressing the generation of voids (hereinafter referred to as “internal voids”) that are internal voids generated inside the ring material. The present invention relates to a processing method for improving the quality of a ring product.

  In fields such as plate rolling, methods for controlling the shape of the rolled material and methods for controlling the rolling speed in addition to controlling the shape of the rolled material have been proposed in order to suppress the generation of internal voids inside the steel material. ing. However, with regard to hot ring rolling, few conventional techniques that focus on improving internal voids can be found. On the other hand, the applicant has proposed a technique that focuses on voids, but has not yet been published. By the way, since this technique prescribes | regulates rolling conditions focusing on crimping | bonding a void, it is a method different from the main method of suppressing generation | occurrence | production of the internal void of this invention.

  On the other hand, in a ring rolling mill, the main roll and mandrel rolls are divided into a plurality of sections in the axial direction to suppress the sliding speed between the roll and the work piece, thereby enabling stable rolling during machining. Means capable of preventing distortion and twist occurring on the surface of the ring material are disclosed (for example, see Patent Document 1).

JP-A-64-75135

  Hot ring rolling is a processing method in which the diameter of the ring material is increased by reducing the thickness of the ring material using a plurality of rolls. Since this method has advantages such as a good yield and a small required processing force, it is widely used for the production of a ring-shaped material having a relatively large diameter.

  Recent ring rolling products have been made near-net shape, and when observed in the axial direction of the workpiece, the peripheral speed of the roll differs depending on the position. Furthermore, a phenomenon in which the peripheral speed of the workpiece varies depending on the position is likely to occur. Thereby, the peripheral speed difference of a roll and a workpiece will arise. Usually, a certain level or more of friction exists between the roll and the workpiece, and a difference in peripheral speed between the two causes local heat generation. This local heat generation may cause defects such as voids in the steel material of the workpiece. In addition, excessive shear strain may be introduced into the workpiece due to a difference in peripheral speed. This shear strain may cause grain boundary fracture and may be a cause of void formation.

  Such voids may be located on the surface or directly below the surface when the forged product is turned and heat treated to form a predetermined bearing. If a material containing voids located on the surface or directly below the surface is processed into a bearing, there is a possibility of causing early defects such as fatigue peeling. Therefore, a processing method that suppresses internal voids, that is, voids in ring rolling products is desired.

  Therefore, the problem to be solved by the present invention is to provide a ring rolling method capable of suppressing the generation of internal voids, that is, voids in a ring rolled product.

  The means of the present invention for solving the above-mentioned problem is to divide each roll of the ring rolling device into an arbitrary plurality of internal voids formed in the product in the hot ring rolling process. Alleviate the difference in the peripheral speed generated between the roll and workpiece, or tilt the rotation main shaft of each of the divided rolls, or apply a lubricant to each of the divided rolls. This is a rolling method that suppresses the generation of internal voids in a ring product, which is a ring rolling product, by detoxifying the difference in peripheral speed generated between the workpieces. That is, it is a ring rolling method in which a main roll and a mandrel are sandwiched with a ring material as a base material, and rolling is performed while rotating the ring material.

  The first means is a method in a ring rolling process in which a main roll and a mandrel sandwich a ring-shaped workpiece as a base material and roll the workpiece while rotating it. Therefore, a portion that contributes to rolling of one or both of the main roll and the mandrel is divided into an arbitrary plurality in the axial direction. The rotation of either one of these arbitrarily divided main rolls or mandrels, or the peripheral speed of the work material by following the rotation shaft of both of them and the ring rolling process of the work material This is a rolling method for ring products in which generation is suppressed.

  The second means is a method in a ring rolling process in which a main roll and a mandrel sandwich a ring-shaped workpiece as a base material and roll while rotating the workpiece. Therefore, a portion that contributes to rolling of one or both of the main roll and the mandrel is divided into an arbitrary plurality in the axial direction. Either or both of the rotation main shaft of the main roll divided into any plural number and the rotation main shaft of the mandrel divided into any plural number are inclined with respect to the workpiece, and the main division divided into any plural number Rolling of ring products that suppresses the generation of internal voids by ring rolling the work piece with the relative peripheral speed between the roll part and any one or both of the divided mandrels and the work piece minimized. Is the method.

  In the third means, the method of ring rolling the workpiece is aimed at a portion where the difference between the circumferential speed of one or both of the main roll and the mandrel and the circumferential velocity of the workpiece is large. It is a rolling method of a ring product that suppresses the generation of internal voids in the first means or the second means by subjecting a workpiece to ring rolling while applying a lubricant.

  By adopting the above-mentioned means, the present invention can produce a near net shape product of a ring product by ring rolling, and in the first means, each roll of either or both of a main roll and a mandrel The portion that contributes to rolling by contacting with the workpiece is divided into any number of sections in the axial direction, for example, divided into five sections, and either one of these divided main rolls or mandrels is rotated or both By rotating the workpiece, the workpiece is driven at the peripheral speed generated between it and the workpiece, so that each roll part in contact with the workpiece accurately grasps the workpiece and keeps the ring -Ring processing is possible, so between the work piece and each roll part, each roll part rotates independently by friction and occurs between the work piece and each roll part That the difference in peripheral speed can be relaxed, so that the formation of internal voids is suppressed workpiece that is rolled.

  Further, in the second means, the rotation main shaft of each divided roll part of either or both of the main roll and the mandrel is inclined and rotated, and the relative peripheral speed between each divided roll part and the workpiece is minimized. As the ring rolling process is performed, when the work piece is cut in a plane perpendicular to the rolling direction of the ring rolling process, and the cross section has a certain taper angle, the roll spindle is adjusted to the taper angle. Thus, the difference in peripheral speed between the roll portions can be made close to zero, and the formation of internal voids in the rolled workpiece is suppressed.

  In the third means, the work material is provided by applying a lubricant to a portion having a large difference between the peripheral speed of one or both of the main roll and the mandrel and the peripheral speed of the work material rotating in contact with the main roll and the mandrel. And the difference between the peripheral speeds generated between the rolls can be made harmless, and the formation of internal voids in the rolled workpiece can be further suppressed.

It is a figure which shows the cross section of the ring rolling apparatus which concerns on this invention. It is a figure which shows typically the cross section of the main roll and workpiece which are two inclined mandrels symmetrical in the vertical direction, and the part which contributes to rolling is a surface perpendicular | vertical to a rotating shaft. It is a figure which shows the cross section of a drum-shaped mandrel and a workpiece. (A) is a schematic diagram of a workpiece surface divided into five sections, (b) is a cross-sectional view of two vertically inclined mandrels and workpiece, and (c) is the surface of the workpiece. The schematic diagram which gave lubricating oil is shown. It is a figure which shows the various dimensions of the workpiece shown in FIG. It is a figure which shows the cross section of the ring-shaped product which shape | molded both the outer diameter part and the inner diameter part. (A) is an inner diameter part, (b) is an outer diameter part, (c) is typical sectional drawing which shows the ring-shaped product which shape | molded both the inner diameter and the outer diameter, respectively. FIG. 8 is a cross-sectional view schematically showing a main roll and a mandrel divided into five sections forming the ring-shaped product of FIG. 7, wherein (a) is a mandrel, (b) is a main roll, and (c) is a mandrel and main roll. It is sectional drawing which shows this typically. It is sectional drawing which shows typically processing of the ring-shaped product which shape | molded both the outer diameter part and inner diameter part shown in FIG. 6 with the upper and lower main rolls and the upper and lower mandrels. It is a figure which shows typically the cross section of the main roll, the mandrel, and workpiece which ring-roll the workpiece which has a shape.

  EMBODIMENT OF THE INVENTION The form for implementing this invention is demonstrated with reference to a table | surface and attached drawing. As shown in FIG. 1, the present invention is a method used in the case of manufacturing a near net shape product 9 by ring rolling a workpiece 5 with a ring rolling device 1. As shown in FIG. 1, this ring rolling device 1 is a ring-shaped workpiece 5 that is ring-shaped with two main rolls 2 that are inclined in an upper and lower V shape and a mandrel 3 in this example. Rolling is performed. In this case, the workpiece 5 is supported by the backup roll 11 located on the opposite side of the center 5a of the ring-shaped workpiece of the workpiece 5. In addition, the rotation main axis of the main roll 2 is indicated by 2a, the rotation main axis of the mandrel 3 is indicated by 3a, the center of the workpiece is indicated by 5a, and the rotation main axis of the backup roll 11 is indicated by 11a.

  The method according to the first aspect of the present invention is the method of the ring rolling device 1 in the axial direction 10 generated between the work 5 and each roll composed of the main roll 2 and the mandrel 3 shown in FIG. This is a method of ring rolling by reducing the difference in peripheral speed. In order to alleviate the difference in the peripheral speed of this method, the part 2b contributing to the rolling of the main roll 2 or the part 3b contributing to the rolling of the mandrel 3 in either one or both of the main roll 2 and the mandrel 3 is provided. Divide into 5 sections in the axial direction 10. As shown in FIG. 3, a portion 3 b contributing to rolling of the mandrel 3 is in contact with the workpiece 5 while the mandrel 3 rotates around the rotation main shaft 3 a. As shown to (a) of FIG. 4, let the part 3b which contributes to the rolling formed by dividing | segmenting the mandrel 3 into 5 sections be each independent part 3c. A rolling method in which the generation of internal voids is suppressed by rotating these independent portions 3c according to the peripheral speed generated between the workpiece 5 and the ring rolling of the workpiece 5 independently. It is.

  The method according to the second aspect of the present invention is the same as the above method in that the ring rolling device 1 includes a main roll 2 and a mandrel 3 shown in FIG. The ring rolling process is performed by relaxing the difference in the peripheral speed in the axial direction 10 generated in the process. In order to alleviate the difference in the peripheral speed of this method, the part 2b contributing to the rolling of the main roll 2 or the part 3b contributing to the rolling of the mandrel 3 in either one or both of the main roll 2 and the mandrel 3 is provided. Divide into 10 axial directions. Next, as shown in FIG. 4 (b), the rotation main shaft 3a of the main roll 2 or the rotation main shaft 3a of the mandrel 3 of either one or both of the divided main roll 2 and mandrel 3 is shown. Inclination of two mandrels 3 whose upper and lower rotating main shafts 3a are inclined by 10 °, and combining these two upper and lower mandrels 3 and ring rolling processing the workpiece 5, suppressed the generation of internal voids. It is a rolling method.

  In the method of the third embodiment, as an embodiment of claim 3, the circumferential direction in the axial direction 10 generated between each roll composed of the main roll 2 and the mandrel 3 of the ring rolling device 1 and the workpiece 5 is used. It is a method to make the difference in speed harmless. For this detoxification, the figure between the peripheral speed of the part 3 and the peripheral speed of the workpiece 5 that contribute to the rolling of either one or both of the rolls composed of the main roll 2 and the mandrel 3 4 (c), a rolling method that includes subjecting the workpiece 5 to ring rolling while applying a lubricant to the portion 8 with a large difference in peripheral speed. In FIG. 4C, the mandrel 3 is removed and only the workpiece 5 is shown, and the width of the outer diameter portion of the workpiece 5 is indicated by 7a.

  Specific examples of the above rolling method are shown below. The ring-shaped product 9, which is the near net shape product 9 a shown in FIG. 7, made of the workpiece 5 after the ring rolling process, is an inner diameter portion shown in FIG. 7A in the inner diameter portion 6 of the workpiece. The width direction of the width 6a is shaped to have a taper of an angle of 10 ° from the axial direction from the width center portion 6b to the width end portion 6c. However, the width direction of the width 7a of the outer diameter portion in the outer diameter portion 7 of the workpiece is not shaped and has an annular surface parallel to the axial direction. Accordingly, as shown in FIG. 5, the outer diameter is 220 mm, the inner diameter of the central portion 6b in the axial direction is 180 mm, and the outer diameter width 7a is 150 mm. As shown in FIG. 7A, the ring-shaped product 9 made of the workpiece 5 is a near-net-shaped product 9a formed into a near-net shape, and the inner diameter surface of the ring-shaped product 9 has a taper of 10 °. Have an angle.

  On the other hand, the ring-shaped product 9, which is the near net shape product 9 a shown in FIG. 7, made of the workpiece 5 after the ring rolling process, is an outer portion shown in FIG. 7B in the inner diameter portion 6 of the workpiece. The width direction of the width 7a of the diameter portion is shaped to have a taper of an angle of 10 ° from the axial direction from the width center portion 7b to the width end portion 7c. However, in the inner diameter portion 6 of the workpiece, the width direction of the inner diameter portion 6a is not shaped and has an annular surface parallel to the axial direction. The ring-shaped product 9 made of the workpiece 5 is a near-net-shaped product 9a formed into a near-net shape, and the outer diameter surface of the ring-shaped product 9 has a taper angle of 10 °.

  In the ring rolling method of the workpiece 5, a condition in which the roll is divided as shown by a dividing line 4 so as to satisfy the means of claim 1, and a rotation main shaft of the roll so as to satisfy the means of claim 2. The near net shape is formed by ring rolling according to a method having a condition in which the inner diameter portion 5c is lubricated so as to satisfy the means of claim 3 and a method not having these conditions. Product 9a was produced. Next, the presence or absence of internal voids and the presence or absence of internal voids formed in these near net shape products 9a were evaluated and shown in Table 1. In Table 1, regarding the evaluation of the presence or absence of internal voids, high-accuracy ultrasonic flaw detection was performed and the frequency of the number of defects was evaluated.

  In Table 1, No. of the condition of the evaluation item consisting of roll division, spindle inclination, lubrication and void evaluation. Of No. Since the number is 1 to 64, Table 1 is divided into the following three tables, Table 1-1, Table 1-2, and Table 1-3.

  Table 1-1 shows the condition No. 1-No. 8 has a taper of an angle of 10 ° from the axial direction from the central part 6b of the width 5b of the inner diameter part 6b of the inner diameter part 6 of the workpiece to the end part 6c of the width. This is a ring rolling method for the ring-shaped product 9. 9-No. 16 has a taper of an angle of 10 ° from the axial direction from the width 6b of the central portion of the outer diameter portion 7a of the outer diameter portion 7 of the workpiece to the end portion 7c of the width, as shown in the target shape. This is a ring rolling method of the ring-shaped product 9. These show roll splitting, spindle tilt, lubrication and void evaluation. From Table 1-1, those satisfying any two conditions among the conditions of roll division, spindle inclination, and lubrication were evaluated as “good” and no defects due to the generation of internal voids. Even if only one condition satisfies the conditions of the main shaft inclination, the evaluation is good, and there is no defect due to the generation of internal voids. No. No. 2 shows that the condition roll division is only on the inner diameter side. In the case of No. 10, the roll division of the condition was only on the outer diameter side, and the evaluation of the void was Δ in the case where the main shaft inclination and lubrication were not performed, and there were few and small defects. No. No. 4 that only lubricates, and No. 4 In the case of applying lubrication only to the outer diameter side of 12, a defect due to the generation of a small internal void occurred. No. 1 and no. When the three conditions of roll division, main shaft inclination, and lubrication were not implemented, a large number of large internal voids occurred and a large number of large defects occurred.

  Table 1-2 shows the condition Nos. 17-No. 40, but Table 1-3 shows No. 40. 41-No. 64 is shown. These are the ring-shaped products 9 shown in FIG. 6 in which the inner diameter portion 6 of the workpiece and the outer diameter portion 7 of the workpiece are both shaped, and are shown in the target shapes of Table 1-2 and Table 1-3. A taper having an angle of 10 ° from the axial direction from the central portion 6b of the width 6a of the inner diameter portion 6a of the workpiece to the end portion 6c of the width, and the outer diameter portion of the workpiece 7 is a product produced by the ring rolling method of the ring-shaped product 9 having a taper of an angle of 10 ° from the axial direction from the central portion 7b of the width 7 to the end portion 7c of the width.

  In this case, if both the outer diameter and inner diameter are inclined, the No. 26, 27, 28, 38, 39, 40 or No. 50, 51, 52 and no. As shown in 62, 63 and 64, the evaluation was “good”, and no defect of the internal void was detected. No. No. 36 roll division was performed only on the outer diameter side, spindle inclination was performed only on the inner diameter side, and lubrication was applied only on the inner diameter side. No. 46 was divided into only the inner diameter side, the main shaft was tilted only on the outer diameter side, and lubrication was applied only on the inner diameter side. No. 58 was divided into both outer and inner diameters, the main shaft was tilted only on the outer diameter side, and lubrication was applied only on the inner diameter side. In the case where 60 rolls were divided on both the outer and inner diameters, the spindle was tilted only on the inner diameter side, and lubrication was applied only on the outer diameter side, the evaluation was also “good”, and no defects in internal voids were detected.

  No. In No. 22, roll division was not performed, the main shaft was inclined only on the outer diameter side, and lubrication was applied only on the inner diameter side, and defects due to a small number of small internal voids occurred on the inner diameter side. No. In No. 24, the roll was not divided, the main shaft was inclined only on the inner diameter side, and lubrication was applied only on the outer side, and defects due to a small number of small internal voids occurred on the outer diameter side. No. In the case of No. 34, only the outer diameter side was divided into rolls, only the outer diameter side was inclined to the main shaft, and only the inner diameter side was lubricated, and Δ was defective due to a small number of small internal voids on the inner diameter side. No. In No. 35, only the outer diameter side was divided into rolls, the main axis was inclined only on the inner diameter side, and no lubrication was given. In Δ, defects due to a small number of small internal voids occurred on the outer diameter side. No. In No. 37, the roll was divided only on the outer diameter side, the main shaft was inclined only on the inner diameter side, and lubrication was imparted only on the inner diameter side, and defects due to a small number of small internal voids occurred on the outer diameter side. No. In the case where only the inner diameter side of 44 was divided into rolls and only the outer diameter side was tilted with the main shaft and no lubrication was given, a defect due to a small number of small internal voids occurred on the inner diameter side. No. When the inner diameter side of 45 was divided into rolls, the main shaft was inclined only on the outer diameter side, and lubrication was imparted only on the outer diameter side, Δ caused defects due to a small number of small internal voids on the inner diameter side. No. When the outer and inner diameter sides of 53 were divided into rolls, the main shaft was not inclined, and lubrication was not applied, Δ was a defect due to a small number of small internal voids at the outer and inner diameters. No. When the outer and inner diameter sides of 54 were divided into rolls, the main shaft was not inclined, and lubrication was imparted only on the outer diameter side, a defect due to a small number of small internal voids occurred on the inner diameter side. No. When the outer and inner diameter sides of 55 were divided into rolls, the main shaft was not inclined, and lubrication was applied only to the inner diameter side, a defect was caused by a small number of small internal voids on the outer diameter side. No. When the outer and inner diameter sides of 56 were divided into rolls, the main shaft was inclined only on the outer diameter side, and lubrication was not applied, Δ caused defects due to a small number of small internal voids on the inner diameter side. No. In the case where the outer and inner diameter sides of 57 were divided into rolls, the main shaft was inclined only on the outer diameter side, and lubrication was applied only on the outer diameter side, defects due to a small number of small internal voids occurred on the inner diameter side. No. In the case where the outer and inner diameter sides of 59 were divided into rolls, the main shaft was inclined only on the inner diameter side, and lubrication was not applied, Δ was a defect due to a small number of small internal voids on the outer diameter side. Furthermore, no. In the case where the outer and inner diameter sides of 61 were divided into rolls, the main shaft was inclined only on the inner diameter side, and lubrication was applied only on the outer diameter side, defects due to a small number of small internal voids occurred on the outer diameter side.

  No. In the case where the 17 rolls were not divided, the main shaft was not tilted, and the lubrication was not applied, XX showed defects due to a large number of large internal voids on both the outer diameter side and the inner diameter side. No. In the case where the 18 rolls were not divided, the main shaft was not inclined, and lubrication was applied only to the outer diameter side, defects due to numerous internal voids occurred on the inner diameter side. No. In the case where 19 rolls were not divided, the main shaft was not inclined, and the lubrication was applied only to the inner diameter side, defects due to numerous internal voids occurred on the outer diameter side. No. When 20 rolls were not divided and the main shaft was inclined only on the outer diameter side, and lubrication was not applied, the defect was caused by many internal voids on the inner diameter side. No. In the case where the main shaft is inclined only on the outer diameter side and lubrication is applied only on the outer diameter side without dividing the roll 21, defects due to numerous internal voids occurred on the inner diameter side. No. In the case where the main shaft was inclined only on the inner diameter side and the lubrication was not applied, no defects were generated due to many internal voids on the outer diameter side. No. In the case where the roll was divided only on the outer diameter side of 29 and the main shaft was not inclined and lubrication was not applied, defects due to numerous internal voids occurred on the inner diameter side. No. In the case where only the outer diameter side of 30 was divided into rolls, the main shaft was not inclined, and lubrication was applied only to the outer diameter side, defects due to numerous internal voids occurred on the inner diameter side. No. In the case where only the outer diameter side of 32 was divided into rolls, the main axis was inclined only on the outer diameter side, and lubrication was applied only on the outer diameter side, defects due to numerous internal voids occurred on the inner diameter side. No. In the case where only the outer diameter side of 33 was divided into rolls, the main axis was inclined only on the outer diameter side, and lubrication was applied only on the outer diameter side, defects due to numerous internal voids occurred on the inner diameter side. No. In the case where only the inner diameter side of 41 was divided into rolls and the main shaft was not inclined and lubrication was not given, defects due to numerous internal voids occurred on the outer diameter side. No. In the case where only the inner diameter side of 42 was divided into rolls, the main shaft was not tilted, and lubrication was applied only on the outer diameter side, defects due to numerous internal voids occurred on the outer diameter side. No. In the case where only the inner diameter side of 43 was divided into rolls, the main shaft was not inclined, and lubrication was given only to the inner diameter side, defects due to numerous internal voids occurred on the outer diameter side. No. In the case where only the inner diameter side of 47 was divided into rolls, only the inner diameter side was tilted with the main shaft, and no lubrication was given, defects due to numerous internal voids occurred on the outer diameter side. No. When the inner diameter side of 48 was divided into rolls, the main shaft was inclined only on the inner diameter side, and lubrication was applied only on the outer diameter side, defects due to numerous internal voids occurred on the outer diameter side. Furthermore, no. In the case where only the inner diameter side of 49 was divided into rolls, only the inner diameter side was tilted with the main shaft, and lubrication was applied only to the inner diameter side, defects due to numerous internal voids occurred on the outer diameter side.

  FIG. 8 is a view showing a state in which the workpiece 5 is subjected to ring rolling using the main roll 2 or the mandrel 3 or the main roll 2 and the mandrel 3 divided into five sections. 8A, the portion 3b that contributes to the rolling of the mandrel 3 having a vertically symmetrical shape is provided in a drum shape, and the portion 3b that contributes to the drum-shaped rolling is divided into five sections by the dividing line 4. FIG. . On the other hand, the main roll 2 has a section 2b that contributes to rolling in a straight section. By ring rolling with the main roll 2 and the mandrel 3, a ring-shaped product 9 in which the central portion of the inner peripheral surface bulges out is obtained.

  FIG. 8 (b) shows a portion 2b that contributes to rolling in a concave shape by providing a portion 2b that contributes to rolling in the main roll 2 having a concave shape in the center of a vertically symmetrical shape. Was divided into 5 sections by dividing line 4. On the other hand, the mandrel 3 has a section 3b that contributes to rolling in a straight section. By performing ring rolling with the main roll 2 and the mandrel 3, a ring-shaped product 9 in which the central portion of the outer peripheral surface bulges out is obtained.

  8C, the portion 3b contributing to the rolling of the mandrel 3 having a vertically symmetrical shape is provided in a drum shape, and the portion 3b contributing to the drum-shaped rolling is divided into five sections by the dividing line 4. . Furthermore, a portion 2b that contributes to rolling is provided on the main roll 2 that has a shape in which the central portion of the vertically symmetric shape is recessed in a concave shape, and the portion 2b that contributes to rolling in a shape recessed in this concave shape is divided into five sections by dividing lines 4 Divided into By performing ring rolling with the main roll 2 and the mandrel 3, a ring-shaped product 9 in which the central portion of the inner peripheral surface and the outer peripheral surface bulges out is obtained.

  FIG. 9 shows that the upper and lower main rolls 2 are tilted inward by 10 ° in order to form a ring-shaped product 9 in which the central part of the inner peripheral surface and the outer peripheral surface bulges in a convex shape. The figure shows a figure in which each mandrel 3 is tilted outward by 10 ° and rotated, while the workpiece 5 is rotated around the center 5a of the workpiece to be ring-rolled. Therefore, these are examples of the ring rolling process of the invention according to claim 2.

  In rotation processing such as ring rolling processing, when the workpiece 5 has a shape, the peripheral speed of the workpiece 5 varies depending on the location. When the ring-shaped product 9 shown in FIG. 10 is considered, the diameter of the workpiece 5 is larger than the diameter 5c of the small diameter portion of the left workpiece, and the diameter 5b of the large diameter portion of the right workpiece. For this reason, the peripheral speed of the workpiece 5 is such that the diameter 5c portion of the small diameter portion of the left workpiece is faster than the diameter 5b portion of the large diameter portion of the right workpiece. On the other hand, the diameter of the main roll 2 is such that the diameter 2d of the large diameter portion of the left main roll is larger than the diameter 2e of the small diameter portion of the right main roll. For this reason, the peripheral speed of the main roll is such that the diameter 2d portion of the large diameter portion of the left main roll is faster than the diameter 2e portion of the small diameter portion of the right main roll. Thus, in the ring rolling process, when the shape of the outer diameter portion 7 of the workpiece 5 becomes complicated, the difference in the peripheral speed between the workpiece 5 and the roll at the outer diameter increases. Similarly, when the shape of the inner diameter portion 6 of the workpiece becomes complicated, the difference in the peripheral speed between the workpiece 5 and the roll at the inner diameter increases. As described above, when the difference between the peripheral speeds of the workpiece 5 and the roll becomes large, slipping occurs between the workpiece 5 and the roll as described above, and therefore, local frictional heat generation occurs in the portion. This is a chance to deteriorate the quality of the ring-shaped product 9.

DESCRIPTION OF SYMBOLS 1 Ring rolling apparatus 2 Main roll 2a Rotation main shaft 2b Part contributed to rolling 2c Independent part 2d Diameter of main roll large diameter part 2e Diameter of main roll small diameter part 3 Mandrel 3a Rotation main axis 3b Part contributed to rolling 3c Independent 4 Dividing line 5 Work material 5a Center of work material 5b Diameter of large diameter portion of work material 5c Diameter of small diameter portion of work material 6 Inner diameter portion of work material 6a Width of inner diameter portion 6b Center of width Part 6c Width end part 7 Outer diameter part of workpiece 7a Width of outer diameter part 7b Center part of width 7c End part of width 8 Site with large difference in peripheral speed 9 Ring product 9a Near net shape product 9b Ring shape Product center 10 Axis direction 11 Backup roll 11a Spindle

Claims (3)

  Contributes to rolling one or both of the main roll and mandrel in the ring rolling process in which the base roll and mandrel are sandwiched with a ring-shaped workpiece and rolled while rotating the workpiece. The portion is divided into an arbitrary number in the axial direction, and the workpiece is driven by the rotation of either the main roll or the mandrel divided into these arbitrary plural numbers or the rotation shafts of both, and the peripheral speed, A rolling method for a ring product that suppresses the generation of internal voids, characterized by subjecting the workpiece to ring rolling.   Contributes to rolling one or both of the main roll and mandrel in the ring rolling process in which the base roll and mandrel are sandwiched with a ring-shaped workpiece and rolled while rotating the workpiece. Divide the part into any number of parts in the axial direction, and tilt either or both of the rotation main shaft of the main roll divided into any number of these and the rotation main shaft of the mandrel divided into any number of parts The workpiece is subjected to ring rolling processing with a minimum relative peripheral speed between the work material and one or both of the main roll part divided into any plurality and the mandrel divided into any plurality. A rolling method for ring products that suppresses the occurrence of internal voids.   The method of ring rolling a workpiece is to aim at a site where the difference between the circumferential speed of one or both of the main roll and the mandrel and the circumferential velocity of the workpiece is large and apply the lubricant while applying the lubricant to that site. The rolling method of a ring product that suppresses generation of internal voids according to claim 1 or 2, wherein the work material is subjected to ring rolling.

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