CN102974633B - Swell-shrink drawing molding process and device for reducing pipes - Google Patents

Abstract

The invention relates to the processing of metal pipes, in particular to a method and device for expansion and contraction drawing of pipes with different diameters. The process includes the first step of shrinking the neck: the pipe is installed on the frame, and one end of the pipe is fixed by a pushing seat. The middle part is supported by a protective sleeve installed on the support seat, and then the other end of the pipe is necked through the necking push head; the second step of annealing: the necked pipe is annealed through the annealing device; the third step is drawing : Draw the pipe processed in the second step through the drawing chuck to form a different-diameter tube blank; the fourth step annealing: anneal the different-diameter tube blank through an annealing device; the fifth step is drawing with fixed diameter and wall thickness: The different-diameter tube blank after the fourth step of annealing is subjected to drawing treatment with fixed diameter and wall thickness through the drawing chuck to form a finished product of the different-diameter tube. The advantages of the present invention due to the structure are: the processing quality precision of the reducer is improved, and the production of the relatively slender reducer is realized.

Description

Expansion-shrinkage drawing forming process and device for different-diameter pipes

technical field

The invention relates to metal pipe processing, in particular to an expansion-contraction drawing forming process and a device for improving the quality precision of different-diameter pipes and capable of producing relatively slender different-diameter pipes.

Background technique

The so-called reducer, commonly known as the big and small head, is a kind of pipe fitting used for pipe diameter reduction. The most widely used is on the pipelines of chemical plants. Usually divided into concentric reducer and eccentric reducer. The material of the reducer includes stainless steel reducer, alloy steel reducer, No. 20 rigid reducer, etc.

There are national standards for reducing pipes, such as "Steel Butt Welding Seamless Pipe Fittings" GB/T12459-2005, "Steel Butt Welding Pipe Fittings" GB/T13401-2005 and so on.

The diameter specifications of the reducer range from 25 (big head) * 15 (small head) to 1500 (big head) * 1200 (small head). The minimum length of the reducer is 51 mm and the longest is 610 mm.

The reducing pipe usually adopts the shrinking forming process, the expanding forming process, and the stamping forming process.

The shrinking forming process of the reducer is to put the tube blank with the same diameter as the large end of the reducer tube into the forming die, and press along the axial direction of the tube blank to make the metal move along the mold cavity and shrink into shape. According to the diameter of the reducer, it can be divided into one-time press forming or multiple press forming.

Diameter expansion forming is to use a tube blank smaller than the diameter of the large end of the reducer, and use an inner die to expand the diameter along the inner diameter of the tube blank. The diameter expanding process mainly solves the situation that the reducing pipe with a large diameter is not easy to be formed by reducing the diameter. Sometimes, according to the material and product forming needs, the methods of expanding the diameter and reducing the diameter are used in combination.

In addition to using steel pipes as raw materials to produce reducers, some specifications of reducers can also be produced by stamping steel plates. The shape of the die used for stretching is designed with reference to the size of the inner surface of the reducer, and the blanked steel plate is stamped and stretched with the die.

The cold drawing of the prior art is a traditional metal deformation processing technology, which is widely used in the drawing of prestressed steel bars, steel and copper wires, rods, and pipes. The purpose of this stretching and drawing is to obtain high-precision metal materials, such as cold-drawn aluminum tubes, which can produce high-precision aluminum tubes with high finish and high dimensional accuracy; obtain bars with various shapes and specifications, such as producing hexagonal steel Rods, hexagonal aluminum rods, hexagonal copper rods; obtain high economic benefits, save processing time, reduce machining costs, and save metal materials, such as cold-drawn billets. Generally, the equivalent diameter of the drawn material by cold drawing is not very large, but the aspect ratio is particularly large. When the cold drawing process is used for drawing pipes, only a single diameter can be drawn, and the drawing of pipes with different diameters cannot be realized.

The process method and equipment of the prior art cannot process relatively slender reducers.

Contents of the invention

The purpose of the present invention is to provide a method of expansion-contraction drawing forming that improves the quality accuracy of the reducer and can produce relatively slender reducer.

The technical solution adopted in order to realize the above-mentioned object of the present invention is: a kind of expansion-contraction drawing forming process of the different-diameter pipe, it is characterized in that: this process comprises

The first step of necking: install the pipe on the frame, one end of the pipe is fixed by the push seat, the middle part is supported by the protective sleeve installed on the support seat, and then the other end of the pipe is necked by the neck push head ;

The second step of annealing: annealing the necked pipe through the annealing device;

The third step of drawing: drawing the pipe processed in the second step through the drawing chuck to form a different-diameter pipe blank;

The fourth step of annealing: annealing the blank of the reducing pipe through the annealing device;

The fifth step is to expand the tube, sizing and wall thickness drawing: through the drawing chuck, the different diameter tube blank after the annealing treatment in the fourth step is expanded, that is, the sizing and wall thickness drawing process is performed to form the finished product of the different diameter tube .

Through the above method, the processing quality precision of high-diameter pipes is improved, and the production of relatively slender pipes with different diameters is realized. Specifically, it is possible to manufacture pipes with a diameter of less than 150 mm and a length of less than 4 meters.

Another object of the present invention is to provide an expansion-contraction drawing manufacturing device that improves the quality accuracy of the reducer and can produce relatively slender reducer.

The technical solution adopted in order to realize the above-mentioned purpose of the present invention is: a kind of expansion-contraction drawing-forming device of reducing pipe, wherein the device comprises

The frame (1) and the hydraulic station (2), the pushing baffle (3) fixed on one end of the frame (1), the pushing seat (4) fixed on the pushing baffle (3), the pipe (5 ) is fixed in the pushing seat (4);

The other end of the frame (1) has a movable mold base (6), and the movable mold base (6) moves along the guide post (8) to the end of the pipe (5) under the push of the sleeve (7), and the guide post (8) ) is fixed on both sides of the frame (1), one end of the pipe sleeve (7) is connected with the movable mold base (6), and the other end of the pipe sleeve (7) is fixed on the piston of the hydraulic cylinder controlled by the hydraulic station (2). Rod (9) end;

The pipe (5) is necked by the necking push head installed on the movable die base (6), the necking push head includes a die sleeve (10) fixed on the movable die base (6), and is set on The necking mold (11) in the die set (10), the pipe (5) passes through the necking mold (11), and the movable mold base (6) is pushed through the pipe sleeve (7), and the pipe (5) is in the necking mold ( 11) is pushed and deformed, so that the diameter of the other end of the pipe (5) becomes smaller to achieve necking;

Remove the necking push head from the movable mold base (6) and install it on the fixed mold base (12). The fixed mold base (12) is located at the necking of the pipe (5). The fixed mold base (12) Fix on the frame (1) to realize the positioning of the pipe (5) at the constriction of the pipe (5); the necking of the pipe (5) is clamped by the drawing chuck installed on the movable mold base (6) The drawing chuck includes the core head I (13) fixed with the movable mold seat (6), the core head I (13) is provided with a movable mold cover (14), and the movable mold cover (14) Fixed on the movable mold base (6), a pair of clamping flaps (15) are symmetrically arranged in the movable mold sleeve (14). The outer wall of the clamping flap (15) has a taper, and the inner wall has sharp ring teeth. The clamping flaps ( 15) It forms a drawing die with the core head I (13), and there is a gap between the clip flap (15) and the core head I (13) for the pipe wall of the pipe (5) to penetrate, and the clip flap (15) and the core The head I (13) clamps the pipe wall of the pipe (5) in the gap, and on the outer wall of the movable die sleeve (14) is provided a valve clutch mechanism (16 ); after the flap clutch mechanism (16) controls the flap (15) and the core head I (13) to clamp the pipe wall of the pipe (23), the movable mold base (6) moves away from the pipe along with the sleeve (7) ( 5) The end of the necking port moves to realize the drawing deformation of the pipe (5), so that the pipe (5) forms a different-diameter pipe blank;

Unload the necking push head fixed on the fixed die base (12), and position it through the sizing die (28) fixed on the fixed die base (12) at the variable diameter of the reducer blank; place the core Rod (17) penetrates from the large-diameter end of the reducing pipe blank, and one end of the mandrel (17) is fixed on the pushing baffle (3) after passing through the small-diameter end of the reducing pipe blank, and the mandrel (17) ) has a core head II (29), and the core head II (29) is limited on the inner wall of the pipe (5) at the diameter reduction; replace the drawing die of the above-mentioned drawing chuck, and the drawing after replacement The mold clamps the large-diameter end of the different-diameter tube blank, and the movable mold base (6) moves away from the large-diameter end of the different-diameter tube blank along with the sleeve (7), and the pipe (5) moves with the pipe fixed on the movable mold base (6). The drawing chuck moves integrally, the inner diameter of the small-diameter section of the pipe (5) expands under the action of the core head II (29) of the mandrel (17), and the outer diameter of the small-diameter section of the pipe (5) is fixed on the fixed mold base The sizing mold (28) on (12) is formed in a limited position to realize the sizing and wall thickness of the small-diameter section of the blank of the different-diameter pipe.

Through the above structure, the device shown in the present invention improves the processing quality precision of high-diameter pipes and realizes the production of relatively slender pipes with different diameters. Specifically, it can be said that it can manufacture pipe blanks with a diameter of less than 150 mm and a length of less than 4 meters. of pipes.

The above method and device produced can be widely used in light rail vehicles, subway vehicles or high-speed rail vehicles and other needs

Description of drawings

The invention can be further illustrated by the non-limiting examples given in the accompanying drawings.

Accompanying drawing 1 is the structural representation of the present invention.

Accompanying drawing 2 is the structure diagram of pushing seat of the present invention.

Accompanying drawing 3 is the structure schematic diagram of the necking pushing head of the present invention.

Accompanying drawing 4 is the schematic structural diagram of the drawing collet of the present invention.

Accompanying drawing 5 is the structural diagram of A in accompanying drawing 4.

Accompanying drawing 6 is the structural schematic view of the device of the present invention when the shrink tube is drawn.

Accompanying drawing 7 is the schematic diagram of the drawing structure of the device of the present invention for sizing and wall thickness.

In the figure: 1. Rack; 2. Hydraulic station; 3. Push baffle; 4. Push seat; 5. Pipe material; 6. Moving mold seat; 7. Pipe sleeve; 8. Guide column; Piston rod; 10, mold sleeve; 11, necking mold; 12, fixed mold base; 13, core head I; 14, movable mold sleeve; , rotating shaft; 19, spring; 21, remote control lever; 22, fixing bolt; 23, clamping plate; 24, bolt; 25, support seat; 26, jacket; 27, protective cover; head II.

Detailed ways

Below in conjunction with accompanying drawing and embodiment the present invention will be further described:

A method for expanding and shrinking drawing and forming of different diameter pipes, characterized in that: the process includes

The first step of necking: install the pipe on the frame, one end of the pipe is fixed by the push seat, the middle part is supported by the protective sleeve installed on the support seat, and then the other end of the pipe is necked by the neck push head ;

The second step of annealing: annealing the necked pipe through the annealing device;

The third step of drawing: drawing the pipe processed in the second step through the drawing chuck to form a different-diameter pipe blank;

The fourth step of annealing: annealing the blank of the reducing pipe through the annealing device;

The fifth step is to expand the tube, sizing and wall thickness drawing: through the drawing chuck, the different diameter tube blank after the annealing treatment in the fourth step is expanded, that is, the sizing and wall thickness drawing process is performed to form the finished product of the different diameter tube . The shrinking forming process, expanding forming process and stamping forming process of the prior art cannot process the relative pipe material into a different diameter pipe, but the relative pipe material can be processed into a different diameter pipe through the above process, and the processing of the high reducer pipe is improved. mass precision. Specifically, it can be said that it can manufacture pipes with a diameter of less than 150 mm and a length of less than 4 meters.

In order to further improve the quality of the necking place, so as to improve the quality accuracy of the reducer, in the above embodiment, preferably: the first step of necking and the second step of annealing are alternately processed in multiple passes; in the first step During the necking, the necking mold of a necking push head is replaced every time the necking is narrowed.

In order to further improve the quality of drawing and sizing and wall thickness, so as to improve the quality accuracy of the reducer, in the above embodiment, preferably: the third step of drawing and the fourth step of annealing are alternate multi-pass processing ; In the third step of drawing, the drawing die of a drawing chuck is replaced every time drawing; the drawing die used in the last pass draws the inner diameter and outer diameter of the pipe to be less than the design value.

In the above embodiment, preferably: during the annealing, the temperature in the furnace of the annealing device is uniform, and the temperature difference does not exceed 2°C; the heating time is strictly controlled to ensure that the material is thoroughly burned and the structure of the material is transformed uniformly; There is no sand on the inner and outer surfaces of the pipe.

Referring to accompanying drawings 1 to 7, the expansion and contraction drawing and forming device of the reducer in the accompanying drawing, wherein the device includes

The frame 1 and the hydraulic station 2, the pushing baffle 3 fixed on one end of the frame 1, the pushing seat 4 fixed on the pushing baffle 3, and one end of the pipe 5 is fixed in the pushing seat 4;

The other end of the frame 1 has a movable mold base 6, and the movable mold base 6 moves to the end of the pipe material 5 along the guide column 8 under the push of the pipe sleeve 7. The guide column 8 is fixed on both sides of the frame 1, and the pipe sleeve 7 One end of one end is connected with the movable mold base 6, and the other end of the pipe sleeve 7 is fixed on the end of the piston rod 9 of the hydraulic cylinder controlled by the hydraulic station 2;

The pipe material 5 is necked by the necking pushing head installed on the movable mold base 6, the necking pushing head comprises a die cover 10 fixed on the movable die base 6, and the necking die arranged in the die cover 10 11. The pipe material 5 passes through the necking die 11, and the movable mold base 6 is pushed through the pipe sleeve 7, and the pipe material 5 is pushed and deformed in the necking die 11, so that the diameter of the other end of the pipe material 5 becomes smaller to achieve necking; (the above process The necking of the process is realized by this structure).

The above-mentioned necking push head is removed from the movable mold base 6 and installed on the fixed mold base 12, the fixed mold base 12 is located at the necking place of the pipe material 5, and the fixed mold base 12 is fixed on the frame 1 to realize the 5 Position the pipe material 5 at the constriction; the drawing chuck installed on the movable mold base 6 clamps the necking position of the pipe material 5 for drawing, and the drawing chuck includes a core fixed integrally with the movable mold base 6 The head I13 and the core head I13 are provided with a movable mold cover 14, the movable mold cover 14 is fixed on the movable mold seat 6, and a pair of clamping flaps 15 are symmetrically arranged in the movable mold sleeve 14. The outer wall of the clamping flap 15 has a taper, The inner wall has sharp ring teeth, and the clip 15 and the core head Ⅰ13 form a drawing die, and there is a gap between the clip 15 and the core Ⅰ13 for the pipe wall of the pipe 5 to penetrate, and the clip 15 and the core Ⅰ13 connect the pipe The pipe wall of 5 is clamped in the gap, and a valve clutch mechanism 16 is provided on the outer wall of the movable die sleeve 14 to control the clutch valve 15 and the pipe material 5; the valve clutch mechanism 16 controls the valve valve 15 and the core head I13 to connect the pipe After the pipe wall of 5 is clamped, the movable mold seat 6 moves away from the necking port end of the pipe 5 along with the pipe sleeve 7, so as to realize the drawing deformation of the pipe 5, so that the pipe 5 forms a different-diameter pipe blank; The drawing at the reducing diameter is realized through this structure).

Unload the above-mentioned constriction pushing head fixed on the fixed die base 12, and position it through the sizing die 28 fixed on the fixed die base 12 at the variable diameter place of the reducer blank; The large-diameter end of the blank penetrates, and one end of the mandrel 17 passes through the small-diameter end of the different-diameter pipe blank and is fixed on the pushing baffle 3. The other end of the mandrel 17 has a core head II29, and the core head II29 is limited It is located on the inner wall of the pipe material 5 at the variable diameter; replace the drawing die of the above-mentioned drawing chuck, and clamp the large-diameter end of the blank of the different-diameter pipe through the replaced drawing die, and the movable die seat 6 moves away from the pipe sleeve 7 The large-diameter end of the different-diameter pipe blank moves, and the pipe material 5 moves integrally with the drawing chuck fixed on the movable mold base 6. The outer diameter of the small-diameter section is formed by the sizing mold 28 fixed on the fixed mold base 12 to realize the sizing and wall thickness of the small-diameter section of the different-diameter pipe blank. In this embodiment, the pipe material 5 is fixed in the pushing seat 4 by a fixed pin, and the necking die 11 adopted by the necking pushing head has a plurality of necking dies 11 according to the designed pushing amount, and each necking pushes one by one. Replace a necking die 11; the drawing die structure formed by the tab 15 of the drawing chuck and the core head 15 is used as a drawing die, and the die structure is also used as a drawing die for sizing and wall thickness, according to the design The drawing amount and the design drawing amount of fixed diameter and wall thickness determine the number of drawing dies, and multi-pass drawing is carried out according to the number of drawing dies, so as to improve the quality and precision of the finished pipe with different diameters. In this embodiment, the necking, drawing and expansion of the pipe material 5 are actually achieved through the cooperation of the necking and pushing head, the drawing chuck and the mandrel 17 to form a shaped reducer. (In the fifth step of the above-mentioned process, pipe expansion, sizing and wall thickness drawing are realized through this structure).

In order to facilitate the control operation of the pipe material 5, in the above-mentioned embodiment, preferably: the flap clutch mechanism 16 includes a rotating shaft 18 installed on the flap clutch mechanism 16 and a driving rod inserted into a spring 19, and the spring 19 Located on the outer wall of the flap clutch mechanism 16, the clutch between the flap 15 and the pipe 5 is moved by adjusting the lever. When the flap clutch mechanism 16 is pushed to the right, the flap will move to the left. At this time, the piston rod 9 pulls the sleeve 7 Drive the movable mold base 6 to move to the right, the movable mold base 6 drives the movable mold cover 14 to move to the right, the movable mold cover 14 gives a centripetal pressure to the clamping valve 15, the clamping valve 15 moves to the right along with the movable mold base 6, and the movable mold The inner wall of the sleeve 14 tightly clamps the outer wall of the clamping flap 15, and the ring teeth of the clamping flap 15 firmly bite the pipe material 5, and the core head Ⅰ13 is supported inside the pipe material 5, and the pipe material 5 is powerful, and is pulled to the right by the pulling chuck to carry out drawing deformation.

In order to facilitate the remote control of the flap clutch mechanism 16 , in the above embodiment, preferably: a remote control lever 21 is installed on the top of the flap clutch mechanism 16 .

For the convenience of assembly, in the above embodiment, preferably, the pushing seat 4 and the pushing baffle 3 are fixed together by fixing the fixing bolt 22 through the pushing seat 4 , the pushing baffle 3 and the clamping plate 23 in sequence.

For ease of assembly, in the above embodiment, preferably: the core head I13 is fixed integrally with the movable mold base 6 through bolts 24 .

Since the pipe material 5 is relatively long, under the strong hydraulic thrust, the pipe will collapse or bend, and the middle part of the pipe is a weak link. Therefore, in the above-mentioned embodiment, it is preferred that a protective device is provided at the middle part of the pipe material 5 to prevent the pipe material 5 from deforming. Support base 25, support base 25 is fixed on the frame 1, and overcoat 26 is installed on support base 25, and protective cover 27 is housed in the overcoat 26. This structure effectively prevents the pipe material 5 from being deformed in the process of necking, drawing and expanding to form a shaped reducer, thereby reducing scrap rate and production cost. In this embodiment, the support base 25 can be replaced by the fixed die base 12, the outer cover 26 is installed on the fixed die base 12, and the protective cover 27 is installed in the outer cover 26 to realize the protection of the pipe material 5. In the actual use process, the support base 25 is multiple, evenly distributed in the middle part of pipe material 5.

In the above structure, the expansion-contraction drawing forming device of the same reducing pipe can effectively realize the necking, drawing and pipe expansion in the process of making the pipe material 5 into the reducing pipe. At the same time, through the above-mentioned five-step process, the The processing of the pipe material 5 improves the quality and precision of the finished product of the reducing pipe.

Referring to accompanying drawing 7, pipe material 5 shown in accompanying drawing 7 is exactly the different-diameter pipe that has formed, and just becomes the forming different-diameter pipe after the small-diameter section expands.

Apparently, all the embodiments described above are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

To sum up, the present invention improves the processing quality precision of the reducer and realizes the production of the relatively slender reducer.

Claims (6)

1. An expansion-contraction drawing forming device for a different-diameter pipe, characterized in that: the device includes The frame (1) and the hydraulic station (2), the pushing baffle (3) fixed on one end of the frame (1), the pushing seat (4) fixed on the pushing baffle (3), the pipe (5 ) is fixed in the pushing seat (4); The other end of the frame (1) has a movable mold base (6), and the movable mold base (6) moves along the guide post (8) to the end of the pipe (5) under the push of the sleeve (7), and the guide post (8) ) is fixed on both sides of the frame (1), one end of the pipe sleeve (7) is connected with the movable mold base (6), and the other end of the pipe sleeve (7) is fixed on the piston of the hydraulic cylinder controlled by the hydraulic station (2). Rod (9) end; The pipe (5) is necked by the necking push head installed on the movable die base (6), the necking push head includes a die sleeve (10) fixed on the movable die base (6), and is set on The necking mold (11) in the die set (10), the pipe (5) passes through the necking mold (11), and the movable mold base (6) is pushed through the pipe sleeve (7), and the pipe (5) is in the necking mold ( 11) is pushed and deformed, so that the diameter of the other end of the pipe (5) becomes smaller to achieve necking; Remove the necking push head from the movable mold base (6) and install it on the fixed mold base (12). The fixed mold base (12) is located at the necking of the pipe (5). The fixed mold base (12) Fix on the frame (1) to realize the positioning of the pipe (5) at the constriction of the pipe (5); the necking of the pipe (5) is clamped by the drawing chuck installed on the movable mold base (6) The drawing chuck includes the core head I (13) fixed with the movable mold seat (6), the core head I (13) is provided with a movable mold cover (14), and the movable mold cover (14) Fixed on the movable mold base (6), a pair of clamping flaps (15) are symmetrically arranged in the movable mold sleeve (14). The outer wall of the clamping flap (15) has a taper, and the inner wall has sharp ring teeth. The clamping flaps ( 15) It forms a drawing die with the core head I (13), and there is a gap between the clip flap (15) and the core head I (13) for the pipe wall of the pipe (5) to penetrate, and the clip flap (15) and the core The head I (13) clamps the pipe wall of the pipe (5) in the gap, and on the outer wall of the movable die sleeve (14) is provided a valve clutch mechanism (16 ); after the flap clutch mechanism (16) controls the flap (15) and the core head I (13) to clamp the pipe wall of the pipe (5), the movable mold seat (6) moves away from the pipe along with the sleeve (7) ( 5) The end of the necking port moves to realize the drawing deformation of the pipe (5), so that the pipe (5) forms a different-diameter pipe blank; Unload the necking push head fixed on the fixed die base (12), and position it through the sizing die (28) fixed on the fixed die base (12) at the variable diameter of the reducer blank; place the core Rod (17) penetrates from the large-diameter end of the reducing pipe blank, and one end of the mandrel (17) is fixed on the pushing baffle (3) after passing through the small-diameter end of the reducing pipe blank, and the mandrel (17) ) has a core head II (29), and the core head II (29) is limited on the inner wall of the pipe (5) at the diameter reduction; replace the drawing die of the above-mentioned drawing chuck, and the drawing after replacement The mold clamps the large-diameter end of the different-diameter tube blank, and the movable mold base (6) moves away from the large-diameter end of the different-diameter tube blank along with the sleeve (7), and the pipe (5) moves with the pipe fixed on the movable mold base (6). The drawing chuck moves integrally, the inner diameter of the small-diameter section of the pipe (5) expands under the action of the core head II (29) of the mandrel (17), and the outer diameter of the small-diameter section of the pipe (5) is fixed on the fixed mold base The sizing mold (28) on (12) is formed in a limited position to realize the sizing and wall thickness of the small-diameter section of the blank of the different-diameter pipe. 2. The expansion and contraction drawing and forming device for different-diameter tubes according to claim 1, characterized in that: the flap clutch mechanism (16) includes a rotating shaft (18) installed on the flap clutch mechanism (16) and a threaded Insert the lever in the spring (19). The spring (19) is located on the outer wall of the flap clutch mechanism (16). By adjusting the lever, the clutch between the flap (15) and the pipe (5) is activated. When the flap clutch mechanism ( 16) Push it to the right, and the flap will move to the left. At this time, the piston rod (9) pulls the sleeve (7) to drive the movable mold base (6) to move to the right, and the movable mold base (6) drives the movable mold sleeve (14 ) moves to the right, the movable die sleeve (14) exerts a centripetal pressure on the valve (15), the valve (15) moves to the right along with the movable die base (6), and the inner wall of the movable die sleeve (14) is firmly stuck The outer wall of the clamping flap (15), the annular teeth of the clamping flap (15) tightly bite the pipe (5), and the core head I (13) is supported inside the pipe (5), and the pipe (5) is powerful and pulled Pull the chuck to the right for drawing deformation. 3. The expansion-contraction drawing and forming device for different-diameter tubes according to claim 1 or 2, characterized in that: a remote control rod (21) is installed on the top of the flap clutch mechanism (16). 4. The expansion-contraction drawing and forming device for different-diameter pipes according to claim 1, characterized in that: the fixing bolts (22) pass through the pushing seat (4), the pushing baffle (3) and the clamping plate ( 23), fix the pushing seat (4) and the pushing baffle (3) as one. 5. The expansion-contraction drawing forming device for different-diameter tubes according to claim 1, characterized in that: the core head I (13) is fixed integrally with the movable mold base (6) by bolts (24). 6. The expansion-contraction drawing and forming device for different-diameter pipes according to claim 1, characterized in that: a support seat (25) to prevent deformation of the pipe (5) is provided in the middle of the pipe (5), and the support seat (25) Be fixed on the frame (1), an overcoat (26) is installed on the support base (25), and a protective cover (27) is housed in the overcoat (26).