Diameter expansion cold drawing method and device for seamless steel pipe

Abstract

The present invention discloses a method for expanding the diameter of a seamless steel pipe and a device thereof. The blank pipe is arranged on a blank pipe fixing mechanism, and a driving trolley is started. At this time, a first engaging groove of a first pushing plate of the driving trolley is engaged with a rolling wheel of a T-shaped movable part of a first base frame, and the rolling wheel on the other side of the T-shaped movable part is engaged with a first lower fitting groove, and the T-shaped movable part cannot rotate. The driving trolley then drives the first base frame to move in the first guide groove, and then drives the core rod to pass through the blank pipe through the core rod pushing mechanism. The present invention can realize cold drawing and diameter expansion through a single driving trolley, which is convenient to use and effectively reduces the production line manufacturing cost.

Description

Technical Field

[0001] The invention relates to the field of steel pipe processing, and in particular to a diameter expansion cold drawing method and a device for a seamless steel pipe. Background Art

[0002] In steel pipe processing, the expansion and head making of metal pipes are important production processes when metal pipes are subjected to expansion and cold drawing processing. The end of the blank pipe can only pass through the drawing die after the expansion and head making, and serve as the clamping part of the clamp trolley to achieve traction and drawing. The existing expansion first requires the use of one of the driving mechanisms to push the core rod through the blank pipe and install the cold drawing head at the end, and then use another driving mechanism to push the blank pipe pushing mechanism to push the blank pipe for cold drawing and expansion. Multiple driving mechanisms need to be set up to achieve this, and the working time of both needs to be manually controlled, which increases the manufacturing cost of the production line and the difficulty of use. Summary of the invention

[0003] The purpose of the present invention is to provide a method and device for cold drawing a seamless steel pipe to expand the diameter. The present invention can realize cold drawing and expansion through a single driving cart, which is convenient to use and effectively reduces the production line manufacturing cost.

[0004] The technical solution of the present invention is as follows: a method for expanding and cold drawing a seamless steel pipe, wherein the blank pipe is arranged on a blank pipe fixing mechanism, and the driving trolley is started, at which time the first engaging groove of the first pushing plate of the driving trolley is engaged with the rolling wheel of the T-shaped movable part of the first base frame, and the rolling wheel on the other side of the T-shaped movable part is engaged with the first lower fitting groove, and the T-shaped movable part cannot rotate, and the driving trolley then drives the first base frame to move in the first guide groove, and then drives the core rod to pass through the blank pipe through the core rod pushing mechanism; when the first connecting member reaches the outer end of the first lower fitting groove, the rolling wheel on one side of the T-shaped movable part is embedded in the first lower engaging groove, the T-shaped movable part rotates, and the rolling wheel on the other side is disengaged from the first upper engaging groove and slides out along the first upper fitting groove, and the driving trolley and the first The base frame loses connection, and the end of the core rod reaches the other end of the blank tube. A cold drawing head is set at the end of the core rod, and the head expansion positioning mechanism is lowered to position it; the driving trolley continues to move and passes through the first base frame through the through opening. Then, a side roller of the T-shaped movable part on the second base frame contacts the second upper fitting groove and slides into the second upper embedding groove, so that the T-shaped movable part originally located in the second lower embedding groove rotates and disengages from the second lower embedding groove. The driving trolley drives the T-shaped movable part to move on the second lower fitting groove through the second upper embedding groove, and then the blank tube pushing mechanism on the second base frame moves to push the blank tube forward. At this time, the core rod pushing mechanism that cannot move forward causes relative movement between the core rod and the blank tube, and the cold drawing head realizes cold drawing and expansion of the blank tube end.

[0005] The expansion and cold drawing device for seamless steel pipe to implement the above method comprises a transmission base, two ends of the transmission base are respectively provided with a blank tube fixing mechanism and a core rod pushing mechanism, the core rod pushing mechanism is provided with a core rod, the end of the core rod is provided with a cold drawing head, and a head expansion positioning mechanism and a blank tube pushing mechanism are sequentially provided between the blank tube fixing mechanism and the core rod pushing mechanism. The transmission base comprises a seat body, the seat body is provided with a first guide groove, a driving trolley is provided in the first guide groove, one side of the driving trolley is sequentially provided with a first base frame and a second base frame slidably connected, the first base frame is provided with a through hole corresponding to the driving trolley, the side surface of the driving trolley is provided with a first push plate and a second push plate corresponding to the extension direction of the first guide groove, the bottom of the first push plate is provided with a first upper bonding groove penetrating the inner end thereof, the outer end of the first upper bonding groove is provided with a circular first upper fitting groove, the bottom of the second push plate is provided with a second upper bonding groove penetrating the outer end thereof, and the inner end of the second upper bonding groove is provided with a circular first The cam is an angular channel that is formed on a pair of camming axes and on two edges of the cam, the cam being an arc shaped like a circle with the first and second edges of the cam being brought into contact with each other.

[0006] In the aforementioned seamless steel pipe expansion cold drawing device, the core rod includes a rod body connected to the core rod pushing mechanism, a connecting rod is provided at the end of the rod body, the diameter of the connecting rod is smaller than the diameter of the rod body, a connecting thread is provided at the end of the connecting rod, and a strip limit block is provided on the side of the connecting rod between the connecting thread and the rod body; the cold drawing head includes a cold drawing body and an annular connecting piece, the inner cavity of the cold drawing body is matched with the rod body, the end of the cold drawing body is provided with a connecting sleeve whose inner cavity is matched with the connecting rod, a strip limit groove is provided in the connecting sleeve and the strip limit block is matched, and the inner cavity of the annular connecting piece is provided with an internal thread matched with the connecting thread.

[0007] In the aforementioned seamless steel pipe expansion and cold drawing device, the T-shaped movable member is elastically rotatably connected to the first base frame and the second base frame via a torsion spring.

[0008] In the aforementioned seamless steel pipe expansion cold drawing device, gaps are left between the first push plate and the second push plate and the corresponding step blocks, and the T-shaped movable part is arranged in the corresponding gaps; the connection between the T-shaped movable part and the first base frame is located above the first lower bonding groove, and the connection between the T-shaped movable part and the second base frame is located above the second lower bonding groove.

[0009] In the aforementioned seamless steel pipe expansion and cold drawing device, a connecting plate is provided at the bottom of the second base frame, and the T-shaped movable part is arranged on the connecting plate.

[0010] Compared with the prior art, the present invention has the following beneficial effects:

[0011] 1. A transmission base of the present invention includes a base body, a first guide groove is provided on the base body, a driving trolley is provided in the first guide groove, a first base frame and a second base frame slidably connected are provided on one side of the driving trolley in sequence, a through hole corresponding to the driving trolley is provided on the first base frame, a first push plate and a second push plate corresponding to the extension direction of the first guide groove are provided on the side of the driving trolley, a first upper fitting groove is provided at the bottom of the first push plate through its inner end, a first circular upper fitting groove is provided at the outer end of the first upper fitting groove, a second upper fitting groove is provided at the bottom of the second push plate through its outer end, and a circular second upper fitting groove is provided at the inner end of the second upper fitting groove; step blocks are provided on both sides of the bottom of the first guide groove, a first supporting block is provided on the middle side of the step block on one side, and a step block end on the other side A second supporting block is provided on the side surface of the first supporting block, a first lower fitting groove penetrating the inner end thereof is provided on the top of the first supporting block, a first circular lower fitting groove is provided on the outer end of the first lower fitting groove, a second lower fitting groove is provided on the top of the second supporting block, and a second circular lower fitting groove is provided on the inner end of the second lower fitting groove; a T-shaped movable member rotatably connected is provided on the first base frame and the second base frame, and rolling wheels are provided on both sides of the end of the T-shaped movable member, and two rolling wheels of the T-shaped movable member of the first base frame correspond to the first upper fitting groove and the first lower fitting groove respectively, and two rolling wheels of the T-shaped movable member of the second base frame correspond to the second upper fitting groove and the second lower fitting groove respectively; the core rod pushing mechanism is arranged on the top surface of the first base frame, and the blank tube pushing mechanism is arranged on the top surface of the second base frame; When the first connecting member reaches the outer end of the first lower bonding groove, the rolling wheel on one side of the T-shaped movable member is embedded in the first lower bonding groove, the T-shaped movable member rotates, and the rolling wheel on the other side disengages from the first upper bonding groove and slides out along the first upper bonding groove, and the driving trolley loses connection with the first base frame. At this time, the end of the core rod reaches the other end of the blank tube, and a cold plate is set at the end of the core rod. The head is pulled out, and the head expansion positioning mechanism is lowered to position it; the driving trolley continues to move, and one side roller of the T-shaped movable part on the second base frame contacts the second upper fitting groove and slides into the second upper fitting groove, so that the T-shaped movable part originally located in the second lower fitting groove rotates and disengages from the second lower fitting groove, and the driving trolley drives the T-shaped movable part to move on the second lower fitting groove through the second upper fitting groove, thereby moving the blank tube pushing mechanism on the second base frame to push the blank tube forward. At this time, the core rod pushing mechanism that cannot move forward causes the core rod and the blank tube to move relative to each other, and the cold drawing head realizes cold drawing and diameter expansion of the end of the blank tube. Only a single driving mechanism of the driving trolley is required to realize the complete processing process, and when in use, only the start and stop of the driving trolley need to be controlled, which is highly convenient to use;When resetting, the control driving trolley moves back, and the two T-shaped movable parts rotate in the opposite direction to reconnect with the first upper fitting groove and the second lower fitting groove, so as to facilitate and quickly carry out the next steel pipe processing. ;

[0012] 2. The core rod of the present invention comprises a rod body connected to the core rod pushing mechanism, the end of the rod body is provided with a connecting rod, the diameter of the connecting rod is smaller than the diameter of the rod body, the end of the connecting rod is provided with a connecting thread, and the side of the connecting rod between the connecting thread and the rod body is provided with a strip limit block; the cold-drawn head comprises a cold-drawn main body and an annular connecting piece, the inner cavity of the cold-drawn main body is matched with the rod body, the end of the cold-drawn main body is provided with a connecting sleeve whose inner cavity is matched with the connecting rod, the connecting sleeve is provided with a strip limit groove which is matched with the strip limit block, and the inner cavity of the annular connecting piece is provided with an internal thread which is matched with the connecting thread; when the core rod passes through the blank tube, the cold-drawn main body is directly sleeved on the core rod, and it is ensured that the strip limit block is engaged with the strip limit groove, and then the internal thread of the annular connecting piece is connected with the connecting thread to fix the cold-drawn main body. Compared with the traditional cold-drawn head which needs to be installed by twisting the whole, direct sleeve installation is more labor-saving. At the same time, the combination of the strip limit block and the strip limit groove can prevent the cold-drawn head from being accidentally twisted, thereby improving the reliability of use.

[0013] 3. In the present invention, gaps are left between the first push plate and the second push plate and the corresponding step blocks, and the T-shaped movable part is arranged in the corresponding gaps; the connection between the T-shaped movable part and the first base frame is located above the first lower fitting groove, and the connection between the T-shaped movable part and the second base frame is located above the second lower fitting groove; ensuring that the T-shaped movable part is not blocked during rotation, thereby improving the reliability of the device during operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the structure of the present invention;

[0015] Figure 2 It is a structural schematic diagram of the transmission base of the present invention;

[0016] Figure 3 It is a partial structural schematic diagram of the first push plate of the present invention;

[0017] Figure 4 It is a partial mechanism schematic diagram of the second push plate of the present invention;

[0018] Figure 5 It is a structural schematic diagram of the first lower engaging groove of the present invention;

[0019] Figure 6 is a partial structural schematic diagram of the second chassis of the present invention;

[0020] Figure 7 It is a structural schematic diagram of the cold drawing head of the present invention;

[0021] Figure 8It is a schematic diagram of the cross-sectional structure of the core rod and the cold-drawn head of the present invention.

[0022] Reference numerals

[0023] 1. Transmission base; 2. Billet tube fixing mechanism; 3. Core rod pushing mechanism; 4. Core rod; 5. Cold drawing head; 6. Head expansion positioning mechanism; 7. Billet tube pushing mechanism; 8. Base body; 9. First guide groove; 10. Driving trolley; 11. First base frame; 12. Second base frame; 13. Passing port; 14. First push plate; 15. Second push plate; 16. First upper fitting groove; 17. First upper fitting groove; 18. Second upper fitting groove; 19. Second upper fitting groove; 20 , step block; 21, first support block; 22, second support block; 23, first lower fitting groove; 24, first lower engaging groove; 25, second lower fitting groove; 26, second lower engaging groove; 27, T-shaped movable part; 28, rolling wheel; 29, rod body; 30, connecting rod; 31, connecting thread; 32, strip limit block; 33, cold-drawn body; 34, annular connecting part; 35, connecting sleeve; 36, strip limit groove; 37, internal thread; 38, connecting plate. DETAILED DESCRIPTION

[0024] The present invention is further described below in conjunction with the accompanying drawings and embodiments, but they are not intended to limit the present invention.

[0025] Embodiment: A cold-drawn expansion device for a seamless steel pipe, as shown in the attached Figure 1 As shown, it comprises a transmission base 1, two ends of the transmission base 1 are respectively provided with a blank tube fixing mechanism 2 and a core rod pushing mechanism 3, a core rod 4 is provided on the core rod pushing mechanism 3, and a cold drawing head 5 is provided at the end of the core rod 4, and a head expansion positioning mechanism 6 and a blank tube pushing mechanism 7 are sequentially provided between the blank tube fixing mechanism 2 and the core rod pushing mechanism 3, as shown in the attached Figure 2 To Attachment Figure 6As shown, the transmission base 1 includes a base body 8, a first guide groove 9 is provided on the base body 8, a driving trolley 10 is provided in the first guide groove 9, a guide rail is provided on the first guide groove, a driving wheel adapted to the guide rail is provided at the bottom of the driving trolley, a first base frame 11 and a second base frame 12 which are slidably connected are provided on one side of the driving trolley 10 in sequence, a through opening 13 corresponding to the driving trolley 10 is provided on the first base frame 11, and a first push plate 14 and a second push plate 15 corresponding to the extending direction of the first guide groove 9 are provided on the side of the driving trolley 10. The bottom of the first push plate 14 is provided with a first upper fitting groove 16 that passes through its inner end, and the outer end of the first upper fitting groove 16 is provided with a circular first upper fitting groove 17, and the bottom of the second push plate 15 is provided with a second upper fitting groove 18 that passes through its outer end, and the inner end of the second upper fitting groove 18 is provided with a circular second upper fitting groove 19, and the first upper fitting groove and the second upper fitting groove are both inclined downward; both sides of the bottom of the first guide groove 9 are provided with step blocks 20, and the middle side of the step block 20 on one side is provided with a first support block 21, and the side of the step block 20 on the other side is provided with a first support block 21. A second support block 22 is provided on the side of the end of the step block 20, a first lower fitting groove 23 is provided on the top of the first support block 21, which passes through the inner end thereof, a first circular lower fitting groove 24 is provided on the outer end of the first lower fitting groove 23, a second lower fitting groove 25 is provided on the top of the second support block 22, which passes through the outer end thereof, a second circular lower fitting groove 26 is provided on the inner end of the second lower fitting groove 25, and both the first lower fitting groove and the second lower fitting groove are arranged to face upward in an inclined manner; the first bottom frame 11 and the second bottom frame 12 are both provided with a T-shaped movable member for rotational connection The two rolling wheels 28 are arranged on different sides of the end of the T-shaped movable member 27. The two rolling wheels 28 of the T-shaped movable member 27 of the first chassis 11 correspond to the first upper bonding groove 16 and the first lower bonding groove 23 respectively, and the two rolling wheels 28 of the T-shaped movable member 27 of the second chassis 12 correspond to the second upper bonding groove 18 and the second lower bonding groove 25 respectively; the core rod pushing mechanism 3 is arranged on the top surface of the first chassis 11, and the blank tube pushing mechanism 7 is arranged on the top surface of the second chassis 12; as shown in the attached Figure 7 To Attachment Figure 8As shown, the core rod 4 includes a rod body 29 connected to the core rod pushing mechanism 3, a connecting rod 30 is provided at the end of the rod body 29, the diameter of the connecting rod 30 is smaller than the diameter of the rod body 29, a connecting thread 31 is provided at the end of the connecting rod 30, and a strip-shaped limit block 32 is provided on the side of the connecting rod 30 between the connecting thread 31 and the rod body 29; the cold drawing head 5 includes a cold drawing body 33 and an annular connecting piece 34, the inner cavity of the cold drawing body 33 matches with the rod body 29, the end of the cold drawing body 33 is provided with a connecting sleeve 35 whose inner cavity matches with the connecting rod 30, the connecting sleeve 35 is provided with a strip-shaped limit groove 36 that matches with the strip-shaped limit block 32, and the inner cavity of the annular connecting piece 34 is provided with a connecting sleeve 35 that matches with the connecting rod 30 An internal thread 37 that matches the thread 31; the T-shaped movable member 27 is elastically rotatably connected to the first base frame 11 and the second base frame 12 via a torsion spring, so that it has a reset capability and can quickly fit with each groove; there is a gap between the first push plate 14 and the second push plate 15 and the corresponding step block 20, and the T-shaped movable member 27 is arranged in the corresponding gap; the connection between the T-shaped movable member 27 and the first base frame 11 is located above the first lower fitting groove 23, and the connection between the T-shaped movable member 27 and the second base frame 12 is located above the second lower fitting groove 25; a connecting plate 38 is provided at the bottom of the second base frame 12, and the T-shaped movable member 27 is arranged on the connecting plate 38.

[0026] The seamless steel pipe expansion cold drawing method of the above-mentioned device is used to set the blank pipe on the blank pipe fixing mechanism, and the driving trolley is started. At this time, the first engaging groove of the first pushing plate of the driving trolley is engaged with the rolling wheel of the T-shaped movable part of the first base frame, and the rolling wheel on the other side of the T-shaped movable part is engaged with the first lower bonding groove, and the T-shaped movable part cannot rotate, and the driving trolley then drives the first base frame to move in the first guide groove, and then drives the core rod to pass through the blank pipe through the core rod pushing mechanism; when the first connecting part reaches the outer end of the first lower bonding groove, the rolling wheel on one side of the T-shaped movable part is embedded in the first lower engaging groove, the T-shaped movable part rotates, and the rolling wheel on the other side disengages from the first upper engaging groove and slides out along the first upper bonding groove, and the driving trolley and the first base frame are connected. The frame loses connection, at this time the end of the core rod reaches the other end of the blank tube, a cold drawing head is set at the end of the core rod, and the head expansion positioning mechanism is lowered to position it; the driving trolley continues to move and passes through the first base frame through the through opening, and then a side roller of the T-shaped movable part on the second base frame contacts the second upper fitting groove and slides into the second upper embedding groove, so that the T-shaped movable part originally located in the second lower embedding groove rotates and disengages from the second lower embedding groove, and the driving trolley drives the T-shaped movable part to move on the second lower fitting groove through the second upper embedding groove, and then the blank tube pushing mechanism on the second base frame moves, pushing the blank tube forward, and the core rod pushing mechanism that cannot move forward at this time causes the core rod and the blank tube to move relative to each other, and the cold drawing head realizes cold drawing and diameter expansion of the blank tube end.

Claims

1. A method for cold drawing a seamless steel pipe, characterized in that: The blank tube is set on the blank tube fixing mechanism and the driving trolley is started. At this time, the first engaging groove of the first pushing plate of the driving trolley is engaged with the rolling wheel of the T-shaped movable part of the first base frame, and the rolling wheel on the other side of the T-shaped movable part is engaged with the first lower fitting groove. The T-shaped movable part cannot rotate, and the driving trolley then drives the first base frame to move in the first guide groove, and then drives the core rod to pass through the blank tube through the core rod pushing mechanism; when the first connecting part reaches the outer end of the first lower fitting groove, the rolling wheel on one side of the T-shaped movable part is embedded in the first lower engaging groove, the T-shaped movable part rotates, and the rolling wheel on the other side disengages from the first upper engaging groove and slides out along the first upper fitting groove, the driving trolley loses connection with the first base frame. At this time, the core rod When the end reaches the other end of the blank tube, a cold drawing head is arranged at the end of the core rod, and the head expansion positioning mechanism is lowered to position it; the driving trolley continues to move and passes through the first base frame through the through opening, and then a side roller of the T-shaped movable part on the second base frame contacts the second upper fitting groove and slides into the second upper fitting groove, so that the T-shaped movable part originally located in the second lower fitting groove rotates and disengages from the second lower fitting groove, and the driving trolley drives the T-shaped movable part to move on the second lower fitting groove through the second upper fitting groove, and then the blank tube pushing mechanism on the second base frame moves, pushing the blank tube forward, and at this time, the core rod pushing mechanism that cannot move forward causes the core rod and the blank tube to move relatively, and the cold drawing head realizes cold drawing and diameter expansion of the blank tube end; The method adopts a seamless steel pipe expansion cold drawing device, which comprises a transmission base (1), wherein two ends of the transmission base (1) are respectively provided with a blank tube fixing mechanism (2) and a core rod pushing mechanism (3), a core rod (4) is provided on the core rod pushing mechanism (3), a cold drawing head (5) is provided at the end of the core rod (4), an expansion head positioning mechanism (6) and a blank tube pushing mechanism (7) are sequentially provided between the blank tube fixing mechanism (2) and the core rod pushing mechanism (3), the transmission base (1) comprises a base body (8), a first guide groove (9) is provided on the base body (8), a driving trolley (10) is provided in the first guide groove (9), and one side of the driving trolley (10) is sequentially provided with a first chassis (11) which is slidably connected to the first chassis (11) and the first chassis (11) which is slidably connected to the first chassis (11) and the first chassis (11) and the first chassis (11) are sequentially provided with a ... and the first chassis (11) are sequentially provided with a first chassis (11) which is slidably connected to the first chassis (11) and the first chassis (11) and the first chassis (11) and the first chassis (11) are sequentially provided with a first chassis (11) and the first chassis ( 11) and a second base frame (12), the first base frame (11) is provided with a through opening (13) corresponding to the driving trolley (10), the side of the driving trolley (10) is provided with a first push plate (14) and a second push plate (15) corresponding to the extension direction of the first guide groove (9), the bottom of the first push plate (14) is provided with a first upper fitting groove (16) penetrating the inner end thereof, the outer end of the first upper fitting groove (16) is provided with a circular first upper engaging groove (17), the bottom of the second push plate (15) is provided with a second upper fitting groove (18) penetrating the outer end thereof, the inner end of the second upper fitting groove (18) is provided with a circular second upper engaging groove (19); both sides of the bottom of the first guide groove (9) are provided with step blocks (20), wherein a first supporting block (21) is provided on the side of the middle part of the step block (20) on one side, and a second supporting block (22) is provided on the side of the end part of the step block (20) on the other side, a first lower fitting groove (23) penetrating the inner end of the first supporting block (21) is provided on the top, and a first circular lower fitting groove (24) is provided on the outer end of the first lower fitting groove (23), a second lower fitting groove (25) penetrating the outer end of the second supporting block (22) is provided on the top, and a second circular lower fitting groove (26) is provided on the inner end of the second lower fitting groove (25); the first base frame (11) and the second base frame (12) are both provided with a rotatably connected T-shaped movable member (27), and the two ends of the T-shaped movable member (27) are provided with a plurality of movable members. The two sides are provided with rolling wheels (28); the two rolling wheels (28) of the T-shaped movable member (27) of the first base frame (11) correspond to the first upper bonding groove (16) and the first lower bonding groove (23) respectively; the two rolling wheels (28) of the T-shaped movable member (27) of the second base frame (12) correspond to the second upper bonding groove (18) and the second lower bonding groove (25) respectively; the core rod pushing mechanism (3) is arranged on the top surface of the first base frame (11), and the blank tube pushing mechanism (7) is arranged on the top surface of the second base frame (12); gaps are left between the first push plate (14) and the second push plate (15) and the corresponding step blocks (20), and the T-shaped movable member (27) is arranged in the corresponding gaps;The connection between the T-shaped movable member (27) and the first base frame (11) is located above the first lower fitting groove (23), and the connection between the T-shaped movable member (27) and the second base frame (12) is located above the second lower fitting groove (25).

2. The method for expanding and cold drawing a seamless steel pipe according to claim 1, characterized in that: The core rod (4) comprises a rod body (29) connected to the core rod pushing mechanism (3); a connecting rod (30) is provided at the end of the rod body (29); the diameter of the connecting rod (30) is smaller than the diameter of the rod body (29); a connecting thread (31) is provided at the end of the connecting rod (30); a strip-shaped stop block (32) is provided on the side of the connecting rod (30) between the connecting thread (31) and the rod body (29); the cold drawing head (5) comprises a cold drawing body (33) and an annular connecting piece (34); the inner cavity of the cold drawing body (33) matches the rod body (29); a connecting sleeve (35) is provided at the end of the cold drawing body (33) whose inner cavity matches the connecting rod (30); a strip-shaped stop groove (36) matching the strip-shaped stop block (32) is provided in the connecting sleeve (35); an inner cavity of the annular connecting piece (34) is provided with an internal thread (37) matching the connecting thread (31).

3. The method for expanding and cold drawing a seamless steel pipe according to claim 1, characterized in that: The T-shaped movable member (27) is elastically rotatably connected to the first base frame (11) and the second base frame (12) via a torsion spring.

4. The method for expanding and cold drawing a seamless steel pipe according to claim 1, characterized in that: A connecting plate (38) is provided at the bottom of the second base frame (12), and the T-shaped movable member (27) is arranged on the connecting plate (38).

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