Semi-finished product of seamless metal pipe, forming device and production line of seamless metal pipe

Abstract

The utility model relates to the technical field of superfine metal pipe forming, and particularly discloses a semi-finished product of a seamless metal pipe, a forming device and a production line of the seamless metal pipe. Wherein the semi-finished product of the seamless metal pipe comprises a bending part and two connecting parts which are integrally formed, the two connecting parts are connected with the two sides of the bending part respectively, the bending part is in a sector ring shape, the two connecting parts are obliquely arranged relative to the vertical direction, and the distance between the two connecting parts is gradually reduced in the upward extending direction. The utility model can solve the problems that the gaps of the superfine metal pipe are not tidy enough and the product percent of pass is not high.

Description

Technical Field

[0001] This utility model relates to the field of ultra-fine metal tube forming technology, and in particular to a semi-finished product of seamless metal tube, a forming device, and a production line for seamless metal tube. Background Technology

[0002] Ultra-fine seamless metal tubes are precision components with a wide range of applications, such as medical punctures, which can assist in minimally invasive surgeries. Because the outer diameter of these ultra-fine seamless metal tubes is very small, reaching 0.15mm, their manufacturing process is extremely difficult.

[0003] For example, Chinese utility model patent with publication number CN220240654U discloses a seamless metal tube production line. In this patent document, the seamless metal tube needs to go through multiple processes such as cutting, extrusion, and welding. Among them, the extrusion process is to first pre-press the sheet-like rolled tube raw material into a strip blank with a U-shaped cross section, and then extrude the U-shaped strip blank into a round tube shape through a forming mold.

[0004] However, actual production revealed a problem with this method. Due to the large gap between the two sides of the U-shaped strip blank, when the U-shaped strip blank was directly extruded into an ultra-fine metal tube through the forming mold, the gap of the ultra-fine metal tube was not neat enough. This increased the difficulty of welding the gap in the subsequent process, resulting in a low pass rate. Utility Model Content

[0005] This invention provides a semi-finished product of seamless metal tube, a forming device, and a production line for seamless metal tube, which can solve the problems of uneven gaps and low product qualification rate in ultra-fine metal tubes.

[0006] To solve the above problems, the present invention adopts the following technical solution:

[0007] According to a first aspect of the present invention, an embodiment of the present invention provides a semi-finished seamless metal tube, comprising an integrally formed curved portion and two connecting portions, the two connecting portions being connected to both sides of the curved portion respectively, the curved portion being fan-shaped, the two connecting portions being inclined relative to the vertical direction, and the distance between the two connecting portions gradually decreasing in the upward extending direction.

[0008] In some embodiments, the width of the bent portion is 0.15 mm, and the distance between the outer sides of the upper ends of the two connecting portions is less than 0.15 mm and greater than 0.1 mm.

[0009] In some embodiments, the two connecting portions are symmetrically arranged along the midline of the relative bend.

[0010] In some embodiments, the angular radius of the curved portion is 180°.

[0011] According to a second aspect of the present invention, an embodiment of the present invention provides a forming apparatus for a semi-finished seamless metal tube as described in any of the first aspects above, comprising an upper mold assembly, a lower mold assembly, and a driving assembly, wherein the upper mold assembly is disposed above the lower mold assembly; the lower mold assembly includes a placement groove for placing a strip blank; the upper mold assembly includes an upper punch and two upper concave molds, wherein the width of the lower end of the upper punch is less than the width of the U-shaped groove of the strip blank; the two upper concave molds are respectively disposed on both sides of the upper punch, and each of the bottom ends of the two upper concave molds near the upper punch is provided with a forming notch, wherein the distance between the inner walls of the forming notches of the two upper concave molds gradually decreases in the upward extending direction;

[0012] The driving assembly is connected to the upper punch and the two upper dies. The driving assembly is used to drive the upper punch to first insert into the U-shaped groove of the strip blank, and then drive the two upper dies to move downward so that the inner walls of the forming grooves of the two upper dies press the two sides of the strip blank respectively until the two sides of the strip blank abut against the upper punch to form the semi-finished product of the seamless metal tube.

[0013] In some embodiments, after the semi-finished product of the seamless metal tube is formed, the driving assembly is further used to drive the upper punch to move upward first to the semi-finished product detached from the seamless metal tube, and then drive the two upper dies to move upward to the semi-finished product detached from the seamless metal tube.

[0014] In some embodiments, the lower end of the upper punch includes an abutment portion and an exit portion, the exit portion being located below the abutment portion and connected to the abutment portion; in the downward extending direction, the width of the abutment portion is uniform, and the width of the exit portion gradually decreases; the driving assembly is used to drive the exit portion of the upper punch into the U-shaped groove of the strip blank, and when both sides of the strip blank abut the abutment portion of the upper punch are in contact with the strip blank, the driving assembly is used to stop driving the two upper dies to move downward.

[0015] In some embodiments, the lower end face of the upper punch is arc-shaped.

[0016] In some embodiments, the inner wall of the molded notch includes a planar portion and an arcuate portion, the arcuate portion being located above and connected to the planar portion, the planar portion being planar in shape, and the arcuate portion being arcuate in shape.

[0017] In some embodiments, the placement groove is adapted to the curved portion, the curved portion is located in the placement groove, and both connecting portions are located above the placement groove.

[0018] According to a third aspect of the present invention, an embodiment of the present invention provides a production line for seamless metal tubes, including a forming device for semi-finished seamless metal tubes as described in any of the second aspects above.

[0019] This utility model has at least the following beneficial effects: For the semi-finished seamless metal tube of this utility model, both of its connecting parts are inclined relative to the vertical direction. In the upward extension direction, the distance between the two connecting parts gradually decreases, which is equivalent to reducing the distance between the two sides of the strip blank. In the subsequent extrusion process, the amount of deformation of the connecting parts is smaller, and it is relatively easy to control the position of the gap of the ultra-fine metal tube, so as to improve the flatness of the gap of the ultra-fine metal tube, reduce the difficulty of subsequent welding of the gap, and improve the product qualification rate. Attached Figure Description

[0020] Figure 1 This is a cross-sectional schematic diagram of a semi-finished seamless metal tube according to an embodiment of the present invention.

[0021] Figure 2 This is a schematic cross-sectional view of a strip-shaped billet in the prior art;

[0022] Figure 3 This is a schematic diagram of the structure of a forming device for a semi-finished seamless metal tube according to an embodiment of the present invention.

[0023] Figure 4 for Figure 3 Enlarged view of point A in the middle;

[0024] Figure 5 This is a schematic diagram of the upper punch according to an embodiment of the present invention;

[0025] Figure 6 This is a schematic diagram of the upper concave mold according to an embodiment of the present invention;

[0026] Figure 7 This is a schematic diagram of the structure of a forming device for a semi-finished seamless metal tube according to an embodiment of the present invention before pre-pressing.

[0027] Figure 8 This is a schematic diagram of a structure for placing a strip-shaped blank into a placement groove according to an embodiment of the present invention;

[0028] Figure 9 This is a schematic diagram of the structure of the upper punch and upper die near the strip blank according to an embodiment of the present invention;

[0029] Figure 10 This is a schematic diagram of the structure of the upper punch after it is inserted into the strip blank according to one embodiment of the present invention;

[0030] Figure 11 This is a schematic diagram of the structure of a strip-shaped blank after being extruded by the upper die according to an embodiment of the present invention;

[0031] Figure 12 This is a schematic diagram of the structure of the upper punch after it detaches from the semi-finished seamless metal tube according to an embodiment of the present invention.

[0032] Figure 13 This is a schematic diagram of the structure of the upper concave mold after it is separated from the semi-finished product of the seamless metal tube according to an embodiment of the present invention.

[0033] Figure 14 This is a schematic diagram of the production line for a seamless metal tube according to an embodiment of the present invention.

[0034] The attached figures are labeled as follows:

[0035] The seamless metal tube is a semi-finished product 10, a bent part 11, and a connecting part 12;

[0036] 20 strip blanks, 21 U-shaped grooves;

[0037] A forming device 100 for semi-finished seamless metal tubes includes an upper mold assembly 110, a lower mold assembly 120, a placement groove 121, a drive assembly 130, an upper punch 140, an abutting part 141, an exiting part 142, an upper concave mold 150, a forming notch 160, a flat part 161, and an arc-shaped part 162.

[0038] Unwinding device 31, feeding device 32, positioning device 33, first stamping device 34, second stamping device 35, pre-pressing device 36, stamping forming device 37, welding device 38, detection device 39, finished product cutting device 40, sorting mechanism 41, pulling device 42, and receiving device 43. Detailed Implementation

[0039] This invention provides the following description with reference to the accompanying drawings to aid in a comprehensive understanding of the various embodiments of the invention as defined by the claims and their equivalents. The description includes various specific details to aid understanding, but these details should be considered exemplary only. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the various embodiments described herein without departing from the scope and spirit of the invention.

[0040] In the description of this utility model, the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0041] It should be understood that when one element (e.g., the first element) is “connected” to another element (e.g., the second element), the element may be directly connected to the other element, or there may be an intervening element (e.g., the third element) between the element and the other element.

[0042] An embodiment of this utility model provides a semi-finished seamless metal tube, which is elongated in shape. Figure 1 The cross-sectional structure of the semi-finished seamless metal tube 10 includes an integrally formed bent portion 11 and two connecting portions 12, which can be formed by bending a piece of metal sheet. The two connecting portions 12 are respectively connected to both sides of the bent portion 11. The bent portion 11 is fan-shaped, so that the cross-sectional shape of the semi-finished seamless metal tube 10 is approximately U-shaped.

[0043] Both connecting parts 12 are inclined relative to the vertical direction, and the distance between the two connecting parts 12 gradually decreases in the upward direction. This is equivalent to reducing the distance between the two sides of the strip blank. During the subsequent extrusion forming of the ultra-fine metal tube, because the distance between the two connecting parts 12 is small, the amount of deformation caused by the re-extrusion of the two connecting parts 12 is small. It is relatively easy to control the position of the gap in the ultra-fine metal tube, thereby improving the flatness of the gap, reducing the difficulty of subsequent welding of the gap, and improving the product qualification rate.

[0044] In some embodiments, the width L1 of the bent portion 11 is 0.15 mm, and the diameter of the final seamless metal tube can also be around 0.15 mm. The distance L2 between the outer sides of the upper ends of the two connecting portions 12 is less than 0.15 mm and greater than 0.1 mm, so that the upper ends of the two connecting portions 12 will be relatively close together.

[0045] Furthermore, the thickness of the entire seamless metal tube semi-finished product 10 can be 0.04 mm.

[0046] In some embodiments, the two connecting portions 12 are symmetrically arranged relative to the midline of the bending portion 11. During subsequent extrusion, the two connecting portions 12 approach each other more synchronously, and their deformation is similar, which can further improve the flatness of the gap in the ultra-fine metal tube.

[0047] In some embodiments, the angular radius of the bend 11 is 180°, which is close to a semi-circular shape. When the two connecting portions 12 come close to each other, they form another semi-circular shape together with the solder, thereby forming a relatively regular circular tube shape.

[0048] Before discussing in detail the forming device for the semi-finished seamless metal tube of this utility model, it is necessary to explain the structure of the strip blank, such as... Figure 2 As shown, the strip blank 20 is U-shaped and has a U-shaped groove 21. The forming device for the semi-finished seamless metal tube of this utility model is to extrude the strip blank 20 into a semi-finished seamless metal tube.

[0049] This utility model provides a forming apparatus for a semi-finished seamless metal tube according to any of the above embodiments. Specific details regarding the semi-finished seamless metal tube can be found in the above embodiments and will not be repeated here. Figure 3-6 As shown, the forming apparatus 100 for the semi-finished seamless metal tube includes an upper die assembly 110, a lower die assembly 120, and a drive assembly 130. The upper die assembly 110 is positioned above the lower die assembly 120. The lower die assembly 120 includes a placement groove 121 for placing the strip blank 20. Before extrusion, the strip blank 20 needs to be placed into the placement groove 121. The upper die assembly 110 includes an upper punch 140 and two upper dies 150. The width of the lower end of the upper punch 140 is smaller than the width of the U-shaped groove 21 of the strip blank 20, providing space for the subsequent bending of the two connecting portions 12. Two upper dies 150 are respectively disposed on both sides of the upper punch 140. Each upper die 150 has a forming groove 160 on the bottom end near the upper punch 140. In the upward extending direction, the distance between the inner walls of the forming grooves 160 of the two upper dies 150 gradually decreases. When the upper die 150 is pressed downwards, the two connecting parts 12 can move closer to each other along the inner walls of the forming grooves 160 to bend the two connecting parts 12. The driving assembly 130 is connected to both the upper punch 140 and the two upper dies 150. The driving assembly 130 can drive the upper punch 140 and the two upper dies 150 to move upwards or downwards in the vertical direction.

[0050] When forming the semi-finished product 10 of the seamless metal tube, such as Figure 7 As shown, the conveying mechanism can transport the strip blank 20 to the top of the placement trough 121.

[0051] Then, the conveying mechanism can move the strip blank 20 downwards to place it into the placement groove 121. Alternatively, a drive mechanism connected to the lower die assembly 120 can drive the lower die assembly 120 upwards to place the strip blank 20 into the placement groove 121, forming a shape as shown. Figure 8 The state shown.

[0052] Subsequently, the drive assembly can directly drive the upper punch 140 into the U-shaped groove of the strip blank 20 and proceed with subsequent steps. However, since the distance between the upper punch 140 and the upper die 150 and the lower die assembly is relatively large in the initial position (this is to facilitate product transport), if the upper punch 140 is directly driven into the U-shaped groove of the strip blank 20, the travel of the lower punch 140 is relatively large, making it difficult to control accuracy. Therefore, if... Figure 9As shown, after the strip blank 20 is placed into the placement groove 121, the drive assembly can also drive the upper punch 140 and the upper die 150 to move downward together to get closer to the strip blank 20, shorten the distance between the upper punch 140 and the upper die 150 and the lower die assembly, so as to more accurately control the movement of the upper punch 140 and the upper die 150.

[0053] like Figure 10 As shown, the drive assembly drives the lower end of the upper punch 140 to insert into the U-shaped groove of the strip blank 20, providing conditions for subsequent positioning and connection. The lower end of the upper punch 140 may or may not abut against the strip blank 20.

[0054] like Figure 11 As shown, the drive assembly then drives the two upper dies 150 to move downwards. The inner walls of the forming grooves 160 of the two upper dies 150 press the two sides of the strip blank respectively. As the distance between the inner walls of the forming grooves 160 of the two upper dies 150 gradually decreases in the upward direction, the two sides of the strip blank will gradually move towards the middle until both sides of the strip blank abut against the upper punch 140. The drive assembly stops driving the two upper dies 150 to move downwards to avoid damaging the product. At this time, a semi-finished product 10 of seamless metal tube can be formed.

[0055] In some embodiments, after the seamless metal tube semi-finished product 10 is formed, such as Figure 12 As shown, the drive assembly drives the upper punch 140 to move upward to the semi-finished product 10 that has detached from the seamless metal tube. At this time, the two upper dies 150 respectively abut against the two connecting parts of the semi-finished product 10 of the seamless metal tube to shape the semi-finished product 10 of the seamless metal tube, so as to avoid deformation of the semi-finished product 10 of the seamless metal tube due to the upper punch 140 being pulled upward, and to ensure the quality of the semi-finished product 10 of the seamless metal tube.

[0056] like Figure 13 As shown, after the upper punch 140 disengages from the seamless metal tube semi-finished product 10, the drive assembly then drives the two upper dies 150 upwards until they disengage from the seamless metal tube semi-finished product 10. Thus, the upper die assembly is completely demolded, and the formed seamless metal tube semi-finished product 10 can be removed. Since the two upper dies 150 press against the outer side of the connecting portion, the upward movement of the two upper dies 150 has minimal impact on the seamless metal tube semi-finished product 10. Therefore, this demolding method in this embodiment can reduce the deformation of the seamless metal tube semi-finished product 10, thereby ensuring the quality of the seamless metal tube semi-finished product 10.

[0057] In some embodiments, such as Figure 4 and Figure 5As shown, the lower end of the upper punch 140 includes an abutment portion 141 and an exit portion 142. The exit portion 142 is located below the abutment portion 141 and connected to the abutment portion 141. The abutment portion 141 and the exit portion 142 can be integrally formed. In the downward extending direction, the width of the abutment portion 141 is uniform and within a relatively stable range, while the width of the exit portion 142 gradually decreases.

[0058] During the process of inserting the lower end of the upper punch 140 into the U-shaped groove of the strip blank, the drive assembly drives the exit portion 142 of the upper punch 140 to insert into the U-shaped groove of the strip blank, with the exit portion 142 completely positioned within the U-shaped groove of the strip blank. When both sides of the strip blank abut against the abutment portion 141 of the upper punch 140, the drive assembly stops driving the two upper dies 150 to move downward.

[0059] Therefore, the distance between the upper ends of the two connecting parts of the seamless metal tube semi-finished product 10 will be determined by the width of the abutment part 141. Since the width of the abutment part 141 is uniform, even if the insertion depth of the upper punch 140 into the U-shaped groove of the strip blank has a large error, the distance between the upper ends of the two connecting parts of the seamless metal tube semi-finished product 10 can remain relatively uniform, which reduces the difficulty of forming.

[0060] Meanwhile, after the seamless metal tube semi-finished product 10 is formed, the drive assembly drives the upper punch 140 to move upward to detach from the seamless metal tube semi-finished product 10. Since the width of the exit part 142 gradually decreases in the downward extension direction, the exit part 142 is less likely to touch the two connecting parts of the seamless metal tube semi-finished product 10, and thus less likely to cause the seamless metal tube semi-finished product 10 to detach, further ensuring the quality of the seamless metal tube semi-finished product 10.

[0061] In some embodiments, such as Figure 4 and Figure 5 As shown, the lower end face of the upper punch 140 is arc-shaped, which makes the lower end face of the upper punch 140 smoother and less likely to scratch the semi-finished product 10 of the seamless metal tube, thus ensuring the quality of the semi-finished product 10 of the seamless metal tube and improving the product qualification rate.

[0062] In some embodiments, such as Figure 4 and Figure 6 As shown, the inner wall of the molding notch 160 includes a flat portion 161 and an arc-shaped portion 162. The arc-shaped portion 162 is located above the flat portion 161 and connected to the flat portion 161. The flat portion 161 is planar and the arc-shaped portion 162 is arc-shaped.

[0063] During the downward pressing of the upper die 150, the two sides of the strip blank first abut against the flat parts 161 of the two forming notches 160 respectively. As the upper die 150 presses down further, the two sides of the strip blank abut against the arc-shaped parts 162 of the two forming notches 160 respectively, and bend towards the middle in an arc shape as the arc-shaped parts 162 are formed, so that the end of the connecting part of the semi-finished seamless metal tube 10 is arc-shaped, which is compatible with the ring structure. In the subsequent forming of the seamless metal tube, it is easier to form a regular seamless metal tube.

[0064] In some embodiments, such as Figure 4 As shown, the placement groove 121 is adapted to the bending part, and the bending part is located in the placement groove 121 to stably place the bending part of the strip blank. Both connecting parts are located above the placement groove 121, and the inner wall of the forming notch 160 can be squeezed to the connecting parts.

[0065] In some embodiments, the aforementioned driving components can employ commonly used mold-driving mechanisms, such as hydraulic cylinders or pneumatic cylinders. Multiple driving components can be provided, with the upper punch 140, upper die 150, and lower mold assembly 200 driven by different driving components. Alternatively, only one set of driving components can be provided, using common mold-based sliding control to allow a portion of the upper punch 140, upper die 150, and lower mold assembly 200 to close or open first. Therefore, the specific structure of the driving components will not be described in detail.

[0066] The present invention also provides a production line for seamless metal tubes, including a forming device for semi-finished seamless metal tubes according to any of the above embodiments. For a detailed description of the forming device for semi-finished seamless metal tubes, please refer to the above embodiments, which will not be repeated here.

[0067] In some embodiments, such as Figure 14 As shown, the seamless metal tube production line also includes an unwinding device 31, a feeding device 32, a positioning device 33, a first stamping device 34, a second stamping device 35, a pre-pressing device 36, a stamping forming device 37, a welding device 38, an inspection device 39, a finished product cutting device 40, a sorting mechanism 41, a material pulling device 42, and a material receiving device 43. The unwinding device 31, feeding device 32, positioning device 33, first stamping device 34, second stamping device 35, pre-pressing device 36, seamless metal tube semi-finished product forming device 100, stamping forming device 37, welding device 38, inspection device 39, finished product cutting device 40, sorting mechanism 41, material pulling device 42, and material receiving device 43 are arranged sequentially along the material conveying direction.

[0068] The unwinding device 31 is used to unwind the coiled material and output a strip of metal sheet; the feeding device 32 is used to convey the metal sheet backward; the positioning device 33 is used to position the metal sheet; the first stamping device 34 is used to stamp positioning holes on the metal sheet; the second stamping device 35 is used to punch and cut the metal sheet to form a hollow area on the metal sheet; the pre-pressing device 36 is used to pre-press the metal sheet to form a U-shaped strip blank; the seamless metal tube semi-finished product forming device 100 is used to form the strip blank into a seamless metal tube semi-finished product; the stamping forming device 3... 7 is used to stamp the semi-finished seamless metal tube into a round tube shape of ultra-fine metal tube; welding device 38 is used to fully weld the gap of the ultra-fine metal tube to obtain a seamless metal tube; detection device 39 is used to detect whether the obtained seamless metal tube is qualified; finished product cutting device 40 is used to cut the seamless metal tube from the material strip; sorting mechanism 41 sorts the cut seamless metal tubes, and qualified products and unqualified products are placed separately; pulling device 42 is used to pull the remaining material strip backward to transport the material strip; and collecting device 43 is used to roll up the material strip for easy storage and transportation.

[0069] The terms and words used in the foregoing description and claims are not limited to their literal meaning, but are merely used by the applicant to enable a clear and consistent understanding of the present invention. Therefore, those skilled in the art should understand that the foregoing description of various embodiments of the present invention is for illustrative purposes only, and not intended to limit the present invention as defined by the appended claims and their equivalents.

Claims

1. A semi-finished seamless metal tube, characterized in that: It includes an integrally formed curved part and two connecting parts. The two connecting parts are respectively connected to the two sides of the curved part. The curved part is fan-shaped and the two connecting parts are inclined relative to the vertical direction. The distance between the two connecting parts gradually decreases in the upward direction.

2. The semi-finished seamless metal tube according to claim 1, characterized in that: The width of the curved portion is 0.15 mm, and the distance between the outer sides of the upper ends of the two connecting portions is less than 0.15 mm and greater than 0.1 mm.

3. The semi-finished product of the seamless metal tube according to claim 1, characterized in that: The two connecting parts are symmetrically arranged along the midline of the relative bend.

4. A forming apparatus for a semi-finished seamless metal tube as described in any one of claims 1-3, characterized in that: The device includes an upper mold assembly, a lower mold assembly, and a drive assembly. The upper mold assembly is positioned above the lower mold assembly. The lower mold assembly includes a placement groove for placing a strip-shaped blank. The upper mold assembly includes an upper punch and two upper dies. The width of the lower end of the upper punch is smaller than the width of the U-shaped groove of the strip-shaped blank. The two upper dies are respectively positioned on both sides of the upper punch. Each of the two upper dies has a forming notch on the bottom end near the upper punch. In the upward extending direction, the distance between the inner walls of the forming notches of the two upper dies gradually decreases. The driving assembly is connected to the upper punch and the two upper dies. The driving assembly is used to drive the upper punch to first insert into the U-shaped groove of the strip blank, and then drive the two upper dies to move downward so that the inner walls of the forming grooves of the two upper dies press the two sides of the strip blank respectively until the two sides of the strip blank abut against the upper punch to form the semi-finished product of the seamless metal tube.

5. The forming apparatus for a semi-finished seamless metal tube according to claim 4, characterized in that: After the seamless metal tube semi-finished product is formed, the driving component is also used to drive the upper punch to move upward first to the semi-finished product that has detached from the seamless metal tube, and then drive the two upper dies to move upward to the semi-finished product that has detached from the seamless metal tube.

6. The forming apparatus for a semi-finished seamless metal tube according to claim 4 or 5, characterized in that: The lower end of the upper punch includes an abutment portion and an exit portion. The exit portion is located below the abutment portion and connected to it. In the downward extending direction, the width of the abutment portion is uniform, while the width of the exit portion gradually decreases. The driving assembly is used to drive the exit portion of the upper punch into the U-shaped groove of the strip blank. When both sides of the strip blank abut the abutment portion of the upper punch are in contact with the strip blank, the driving assembly is used to stop driving the two upper dies to move downward.

7. The forming apparatus for a semi-finished seamless metal tube according to claim 4 or 5, characterized in that: The lower end face of the upper punch is arc-shaped.

8. The forming apparatus for a semi-finished seamless metal tube according to claim 4 or 5, characterized in that: The inner wall of the formed groove includes a flat portion and an arc-shaped portion. The arc-shaped portion is located above the flat portion and connected to the flat portion. The flat portion is planar and the arc-shaped portion is arc-shaped.

9. The forming apparatus for a semi-finished seamless metal tube according to claim 4 or 5, characterized in that: The placement groove is adapted to the curved part, the curved part is located in the placement groove, and both connecting parts are located above the placement groove.

10. A production line for seamless metal tubes, characterized in that: The apparatus includes a forming device for a semi-finished seamless metal tube as described in any one of claims 4-9.

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