A large-diameter thick-wall steel pipe precision forming die

Abstract

The application relates to the technical field of steel pipe forming, and discloses a large-diameter thick-wall steel pipe precision forming die which comprises an extruding cylinder, an annular inlay groove is arranged at the bottom of the extruding cylinder, an annular metal inlay piece is arranged on the extruding cylinder, the annular metal inlay piece is slidably installed in the annular inlay groove, the annular metal inlay piece is fixedly installed on the extruding cylinder through bolts, the annular metal inlay piece has heat conductivity and can be disassembled, a conical ring groove is arranged on the inner wall of the extruding cylinder, the conical ring groove is used for forming a steel billet, and a cooling mechanism is arranged. The directional flow of the arc-shaped flow guide block and the dense distribution of cooling water at the bending part of the conical ring groove are matched with each other, heat concentratedly generated can be rapidly taken away, local overheating and softening at the bending part are effectively prevented, the generation condition of the mushroom-shaped built-up burr on the inner wall is fundamentally eliminated, the smooth extrusion forming of the steel billet is ensured, the device vibration caused by the built-up burr friction is effectively avoided, and therefore the dimensional accuracy and the quality of the formed steel pipe are ensured.

Description

Technical Field

[0001] This invention relates to the field of steel pipe forming technology, specifically to a precision forming mold for large-diameter thick-walled steel pipes. Background Technology

[0002] In the hot extrusion forming process of large-diameter, thick-walled steel pipes, the performance of the forming die directly determines the final quality and dimensional accuracy of the steel pipe. Due to the large wall thickness, these steel pipes require extremely high extrusion pressure during forming, resulting in huge frictional resistance between the steel billet and the inner wall of the die.

[0003] Existing forming dies face significant technical challenges when handling the bending forming zone of steel billets (i.e., the bend in the conical annular groove). When the steel billet is pressed downwards within the die and passes through the bending transition area of ​​the conical annular groove, the billet material undergoes intense plastic deformation due to the sharp reduction in the inner diameter of the flow channel at this point. This results in concentrated and explosive frictional heat at the contact surface. This instantaneous high temperature not only causes a rapid increase in the temperature of the die (especially at the bend), potentially softening the metal, but more seriously, the high temperature and high pressure environment easily causes the metal on the surface of the steel billet to adhere to the inner wall of the die, forming a mushroom-shaped built-up edge.

[0004] The formation of these "mushroom-shaped built-up edges" not only damages the surface finish of the mold cavity, leading to scratches or raised defects on the surface of the formed steel pipe, but also alters the stress state of the steel billet. During extrusion, the built-up edge causes unstable intermittent friction between the mold and the steel billet, resulting in severe mechanical vibration throughout the forming device. This vibration affects not only the roundness and wall thickness uniformity of the steel pipe, but in severe cases, it can even cause the mold to crack or the equipment to be damaged. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a precision forming mold for large-diameter thick-walled steel pipes, thus solving the problems of existing technologies.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a precision forming mold for large-diameter thick-walled steel pipes, comprising an extrusion cylinder, wherein the bottom of the extrusion cylinder is provided with an annular groove, and the extrusion cylinder is provided with... An annular metal insert, which is slidably installed in an annular groove, is fixedly installed on an extrusion cylinder by bolts, and is thermally conductive and removable; A conical annular groove is provided on the inner wall of the extrusion cylinder, and the conical annular groove is used for forming steel billets; The cooling mechanism includes a spiral racetrack-shaped water tank formed within an annular metal insert. A water outlet pipe and a water inlet pipe are fixedly installed at the bottom and top of the annular metal insert, respectively. Several rectangular mounting slots are formed within the annular metal insert. Two-way shape memory alloy temperature control springs are installed in each of the rectangular mounting slots. Rhomboid pillars are slidably installed in each of the rectangular mounting slots. Several nitinol bumps are embedded on the surface of each of the rhomboid pillars. Guide slopes are provided on each of the rhomboid pillars.

[0007] Preferably, the spiral racetrack-shaped water troughs are distributed from top to bottom, and the pitch of the spiral racetrack-shaped water troughs gradually decreases when they are 30cm away from the bend of the conical annular groove. The spiral racetrack-shaped water troughs maintain a small pitch distribution when they are 30cm away from the bend of the conical annular groove, and the spiral racetrack-shaped water troughs are distributed closely along the inner diameter change direction of the conical annular groove.

[0008] Preferably, the cooling mechanism further includes spiral ribs fixedly installed on the inner wall of the spiral racetrack-shaped water tank. The spiral ribs are distributed on one side near the conical annular groove and are arranged along the path of the spiral racetrack-shaped water tank.

[0009] Preferably, the rectangular mounting slots are symmetrically distributed, and none of the rectangular mounting slots are on the same horizontal line in the transverse direction.

[0010] Preferably, a plurality of the two-way shape memory alloy temperature control springs are respectively disposed on the opposite side of the plurality of rectangular mounting slots, one end of the plurality of two-way shape memory alloy temperature control springs is fixedly connected to the bottom inner wall of the rectangular mounting slot, and the other end of the plurality of two-way shape memory alloy temperature control springs is in a free state.

[0011] Preferably, the ends of the rhomboid prisms that are far apart from each other are in contact with the ends of the rhomboid prisms that are far apart from ...

[0012] Preferably, a plurality of the nickel-titanium bumps are distributed on the upper and lower surfaces of the rhomboid prism, and the plurality of the upper and lower surfaces are triangular inclined surfaces.

[0013] Preferably, the plurality of the guide slopes and the plurality of upper and lower surfaces all face the water-facing side.

[0014] Preferably, both the outlet pipe and the inlet pipe are connected to the spiral racetrack-shaped water tank, and the spiral racetrack-shaped water tank is provided with several arc-shaped guide blocks.

[0015] Preferably, the plurality of arc-shaped guide blocks are distributed in groups of three on one side away from the conical annular groove within the spiral racetrack-shaped water tank. The middle one and the two behind the plurality of arc-shaped guide blocks are arranged asymmetrically in a triangle. Claw-shaped grooves are formed on the corresponding arc-shaped guide blocks in the plurality of arc-shaped guide blocks. The main channel in the plurality of claw-shaped grooves is wide at both ends and narrow in the middle. The part where the water inlet end of the two branch channels in the plurality of claw-shaped grooves communicates with the branch channel is relatively narrow. The ends of the two branch channels in the plurality of claw-shaped grooves are respectively connected to different positions of the narrower part of the main channel.

[0016] This invention provides a precision forming mold for large-diameter, thick-walled steel pipes. Compared with existing technologies, it has the following advantages: 1. By incorporating a cooling mechanism, the increased water temperature causes the nitinol bumps on the surface of the rhombic prism to harden into cylinders. When water flows along the upper and lower surfaces of the rhombic prism and converges at the rear, the asymmetry in flow velocity and pressure on both sides causes water to detach alternately, forming vortices. The nitinol bumps force the water flow into intense turbulence, reducing scale buildup in the gaps between the bumps and increasing vortex formation. Larger vortices increase heat dissipation efficiency, and the vortices vibrate up and down as they detach from the rhombic prism. Vibration removes scale buildup from the surface of the rhomboid column, preventing scale from forming vortices and reducing heat dissipation efficiency. When the nickel-titanium protrusions stand at high temperatures, the water flow rate increases further, enhancing heat dissipation and quickly carrying away the concentrated heat at the conical annular groove bend. Combined with the reduced pitch at the 30cm bend of the conical annular groove, the contact area between the water flow and the groove increases, effectively preventing localized overheating and softening at the bend and fundamentally eliminating the conditions for mushroom-shaped built-up edge formation on the inner wall. This not only ensures smooth extrusion of the steel billet but also effectively avoids equipment vibration caused by built-up edge friction, thus ensuring the dimensional accuracy and quality of the formed steel pipe.

[0017] 2. By setting up rhomboid columns, the vortex generated by the falling rhomboid columns in the front row becomes the power source for the rear rhomboid columns, causing them to vibrate violently. The vibration energy of multiple rhomboid columns not only effectively improves the self-cleaning force, but this collective resonance can also effectively peel off the thermal boundary layer tightly attached to the inner side of the spiral racetrack-shaped water tank, achieving regional synchronous cooling at the bend of the conical annular groove. Each row of rhomboid columns and the nickel-titanium protrusions on their surfaces continuously compress the flow cross-sectional area, forming a multi-stage cascaded Venturi effect. The water flow is progressively compressed and accelerated as it passes through the rhomboid columns, and is continuously broken up as it repeatedly passes through the nickel-titanium protrusions. This not only maximizes the flow velocity at the rear, but also keeps the entire flow in a high-intensity turbulent state, pushing the heat exchange efficiency to its peak and ensuring that the steel billet can pass smoothly through the bend of the conical annular groove, reducing the occurrence of vibration.

[0018] 3. By incorporating claw-shaped grooves, when scale-laden cooling water flows through the arc-shaped guide blocks, some of the cooling water enters the branch channels and main channel of the claw-shaped grooves. The cooling water entering the main channel, due to its wide-narrow-wide structural design, experiences increased flow velocity upon exiting from the outlet, creating a high-speed water jet that directly impacts the inner side of the spiral racetrack-shaped water tank, enhancing heat dissipation. Simultaneously, the high-speed jet possesses extremely strong shearing force, rebounding behind the inner side of the spiral racetrack-shaped water tank. The impact of this rebound washes away scale from the surfaces of the two arc-shaped guide blocks, keeping the surfaces of the arc-shaped guide blocks and the inside of the spiral racetrack-shaped water tank clean and preventing a decrease in thermal conductivity due to scaling. The cooling water also enters through the two branch channels of the claw-shaped grooves. Because the section connecting to the main channel is relatively narrow, the cooling water discharged from the branch channel also has an impact force. This force can not only impact different locations in the narrow area (throat) of the main channel to prevent the throat of the main channel from being blocked by scale, but also increase the impact force of the main channel, ensuring the heat dissipation effect of the main channel and the effective cooling of the flat area of ​​the conical annular groove. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a front cross-sectional view of the present invention; Figure 3 This is a schematic cross-sectional view of the front portion of the present invention; Figure 4 For the present invention Figure 3 A magnified structural diagram of A in the middle; Figure 5 For the present invention Figure 3 A magnified structural diagram of B in the diagram; Figure 6 For the present invention Figure 3 A magnified structural diagram of C; Figure 7 This is a schematic diagram of the internal structure of the present invention; Figure 8 This is a partial cross-sectional schematic diagram of the single-group arc-shaped guide block mechanism of the present invention.

[0020] In the diagram: 1. Extrusion cylinder; 101. Annular metal insert; 102. Conical annular groove; 103. Spiral racetrack-shaped water tank; 104. Water outlet pipe; 105. Water inlet pipe; 106. Arc-shaped guide block; 1061. Claw-shaped groove; 107. Spiral rib; 108. Rectangular mounting groove; 109. Two-way shape memory alloy temperature control spring; 110. Rhomboid column; 111. Guide slope; 112. Nickel-Titanium protrusion. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] See Figures 1-8 The present invention provides the following two technical solutions: First embodiment: A precision forming mold for large-diameter thick-walled steel pipes, including an extrusion cylinder 1, the bottom of which is provided with an annular groove, and the extrusion cylinder 1 is provided with... An annular metal insert 101 is slidably installed in an annular groove. The annular metal insert 101 is fixedly installed on the extrusion cylinder 1 by bolts. The annular metal insert 101 is thermally conductive and removable. A conical annular groove 102 is provided on the inner wall of the extrusion cylinder 1. The conical annular groove 102 is used for forming steel billets. The cooling mechanism includes a spiral racetrack-shaped water trough 103 within an annular metal insert 101. A water outlet pipe 104 and a water inlet pipe 105 are fixedly installed at the bottom and top of the annular metal insert 101, respectively. Several rectangular mounting slots 108 are provided within the annular metal insert 101. Two-way shape memory alloy temperature control springs 109 are installed within each of the rectangular mounting slots 108. Rhomboid pillars 110 are slidably installed within each of the rectangular mounting slots 108. Several nitinol protrusions 112 are embedded on the surface of each rhomboid pillar 110, and guide slopes 111 are provided on each rhomboid pillar 110. The spiral racetrack-shaped water trough 103 is distributed from top to bottom. The pitch of the spiral racetrack-shaped water trough 103 gradually decreases 30cm from the bend of the conical annular groove 102. The spiral racetrack-shaped water tank 103 maintains a small pitch distribution at a bend of 20cm, closely following the inner diameter variation of the conical annular groove 102. The cooling mechanism also includes spiral ribs 107 fixedly installed on the inner wall of the spiral racetrack-shaped water tank 103. The spiral ribs 107 are distributed on one side close to the conical annular groove 102 and are set along the path of the spiral racetrack-shaped water tank 103. Several rectangular mounting slots 108 are symmetrically distributed, and none of the rectangular mounting slots 108 are on the same horizontal line in the transverse direction. Several two-way shape memory alloy temperature control springs 109 are respectively set on the side of the several rectangular mounting slots 108 that are far away from each other. One end of the several two-way shape memory alloy temperature control springs 109 is fixedly connected to the bottom inner wall of the rectangular mounting slots 108, and the other end of the several two-way shape memory alloy temperature control springs 109 is in a free state. The two-way shape memory alloy temperature control spring 109 bends and pushes the rhomboid column 110 towards the inner side of the spiral racetrack-shaped water tank 103. At this time, the water flow in the spiral racetrack-shaped water tank 103 will not only impact the inner side of the spiral racetrack-shaped water tank 103 under the guidance of the guide slope 111, but also increase the water flow speed and accelerate the heat transfer rate. When the water flows through the upper and lower surfaces of the rhomboid column 110, the temperature rise will cause the nitinol bumps 112 on the surface of the rhomboid column 110 to become hard cylinders. When the water flows along the upper and lower surfaces of the rhomboid column 110 and converges behind it, due to the asymmetry of the flow velocity and pressure on both sides, it will alternately fall off to form vortices. When the water flows through the nitinol bumps 112, it will instantly disrupt the original smooth laminar flow and force it to become violent turbulent flow. The flow can reduce the adhesion of scale in the gaps of the NiTiNo bump 112, and the turbulence generated will increase the formation of vortices. The two vortices passing through the rhomboid column 110 will separate from the rhomboid column 110. The vortices not only increase the heat dissipation efficiency by breaking the thermal boundary layer and stirring the water, but also make the rhomboid column 110 vibrate up and down when it separates from the rhomboid column 110. The vibration will remove the scale that has fallen on the surface of the rhomboid column 110, preventing the scale from covering the rhomboid column 110 and preventing the rhomboid column 110 from generating vortices, which would reduce the heat dissipation efficiency. When the NiTiNo bump 112 stands up at high temperature, it will squeeze the flow channels at the top and bottom of the rhomboid column 110, which will further increase the water flow rate and further improve the heat dissipation effect. It can quickly remove the heat concentrated at the bend of the conical annular groove 102.

[0023] The second implementation method differs from the first implementation method mainly in that: Figure 4 and Figure 6 As shown, the ends of several rhomboid prisms 110 that are far apart from each other are in contact with several two-way shape memory alloy temperature control springs 109. The ends of several rhomboid prisms 110 that are far apart from the two-way shape memory alloy temperature control springs 109 slide and extend into the spiral racetrack-shaped water tank 103. Several NiTiNo bumps 112 are distributed on the upper and lower surfaces of the rhomboid prisms 110. Several upper and lower surfaces are triangular slopes. Several guide slopes 111 and several upper and lower surfaces all face the water-facing side.

[0024] Because the annular metal insert 101 contains multiple rhomboid pillars 110, the vortex caused by the falling off of the front row of rhomboid pillars 110 becomes the power source for the rear row of rhomboid pillars 110, causing the rear row of rhomboid pillars 110 to also vibrate violently. The vibration energy of multiple rhomboid pillars 110 can not only effectively improve the self-cleaning force, but this collective resonance can also effectively peel off the thermal boundary layer inside the spiral racetrack-shaped water tank 103, achieving regional synchronous cooling at the bend of the conical annular groove 102. Each row of rhomboid pillars 110 and the nickel-titanium protrusions 112 on their surfaces are constantly compressing the flow cross-sectional area, forming a multi-stage series Venturi effect. When the water flows through the rhomboid pillars 110, it will be squeezed and accelerated step by step, and continuously broken up when repeatedly passing through the nickel-titanium protrusions 112, which not only maximizes the flow velocity at the rear.

[0025] The third implementation method differs from the first and second implementation methods mainly in that: Figure 1 , Figure 2 , Figure 3 , Figure 5 and Figure 8 As shown, both the outlet pipe 104 and the inlet pipe 105 are connected to the spiral racetrack-shaped water tank 103. Several arc-shaped guide blocks 106 are arranged inside the spiral racetrack-shaped water tank 103. The arc-shaped guide blocks 106 are distributed in groups of three on one side of the spiral racetrack-shaped water tank 103 away from the conical annular groove 102. The middle one and the two behind the arc-shaped guide blocks 106 are arranged in a triangular asymmetrical arrangement. Claw-shaped grooves 1061 are opened on the corresponding arc-shaped guide blocks 106. The main channel of the claw-shaped grooves 1061 is wide at both ends and narrow in the middle. The part where the water inlet end of the two branch channels of the claw-shaped grooves 1061 is connected to the branch channel is relatively narrow. The ends of the two branch channels of the claw-shaped grooves 1061 are respectively connected to different positions of the narrow part of the main channel.

[0026] After the water flows into contact with several sets of arc-shaped guide blocks 106, the water flow impacts the inner wall of the conical annular groove 102 under the guidance of the three arc-shaped guide blocks 106. Combined with the guidance provided by the spiral ribs 107, this allows the hot and cold liquids to mix, improving heat dissipation. When the cooling water flows through the arc-shaped guide blocks 106, some of it enters the branch channels and main channel of the claw-shaped groove 1061. The cooling water entering the main channel, due to its wide-narrow-wide structural design, experiences increased flow velocity when discharged from the outlet, forming a high-speed water flow that directly impacts the inner side of the spiral racetrack-shaped water tank 103, further enhancing heat dissipation. Meanwhile, the high-speed jet possesses extremely strong shearing force, rebounding from the inner side of the spiral racetrack-shaped water channel 103. The impact force of the rebound can wash away the scale on the surface of the two arc-shaped guide blocks 106 behind, keeping the surface of the arc-shaped guide blocks 106 and the inside of the spiral racetrack-shaped water channel 103 clean and preventing a decrease in thermal conductivity due to scale buildup. When the cooling water flows, it enters from the two branch channels of the claw-shaped groove 1061. Because the part connecting to the main channel is relatively narrow, the cooling water discharged from the branch channels also has an impact force, which can impact different positions in the narrow area (throat) of the main channel, preventing the throat of the main channel from being blocked by scale and ensuring the heat dissipation effect of the main channel.

[0027] Furthermore, all content not described in detail in this specification is existing technology known to those skilled in the art, and the model parameters of each electrical appliance are not specifically limited; conventional equipment can be used.

[0028] In use, cooling water is introduced into the spiral racetrack-shaped water tank 103 through the inlet pipe 105 and discharged through the outlet pipe 104, forming a stable cooling circuit. During the extrusion forming process of the steel billet placed in the conical annular groove 102, the steel billet experiences intense friction due to the reduction in inner diameter when passing through the bend of the conical annular groove 102, causing the temperature in that area to rise sharply. The heat is rapidly transferred to the annular metal insert 101, and the side of the annular metal insert 101 closer to the conical annular groove 102 absorbs more heat. The two-way shape memory alloy temperature control spring 109 bends and pushes the rhomboid column 110 towards the inner side of the spiral racetrack-shaped water tank 103. At this time, the water flow in the spiral racetrack-shaped water tank 103 not only flows in the guide... The flow, guided by the inclined surface 111, impacts the inner side of the spiral racetrack-shaped water tank 103, increasing the water flow velocity and accelerating the heat transfer rate. As the water flows through the upper and lower surfaces of the rhombic column 110, the temperature rise causes the Nitino bumps 112 on the surface of the rhombic column 110 to become hard cylinders. When the water flows along the upper and lower surfaces of the rhombic column 110 and converges behind it, due to the asymmetry of flow velocity and pressure on both sides, it will alternately break off to form vortices. When the water flows through the Nitino bumps 112, it will instantly disrupt the originally smooth laminar flow, forcing it to turn. The flow becomes intense turbulence. This turbulence reduces scale buildup in the gaps of the NiTiNo bumps 112. The resulting turbulence increases vortex formation. The two vortices passing through the rhombus 110 will detach from it. These vortices not only increase heat dissipation efficiency by disrupting the thermal boundary layer and agitating the water, but also cause the rhombus 110 to vibrate vertically as it detaches. This vibration dislodges scale from the surface of the rhombus 110, preventing scale from coating the rhombus 110 and thus stopping vortex formation. The reduced thermal efficiency, when the NiTiNo bump 112 stands at high temperature, will squeeze the flow of water at the top and bottom of the rhomboid column 110, which will further increase the water flow rate and improve the heat dissipation effect. It can quickly remove the heat concentrated at the bend of the conical annular groove 102. With the spiral racetrack-shaped water tank 103, the pitch becomes smaller when it is 30cm away from the bend of the conical annular groove 102, the cooling water distribution is more dense, and the contact area with the conical annular groove 102 is increased, which effectively prevents local overheating and softening at the bend and fundamentally eliminates the conditions for the formation of mushroom-shaped accretion nodules on the inner wall. Because the annular metal insert 101 contains multiple rhomboid pillars 110, the vortex caused by the falling off of the front row of rhomboid pillars 110 becomes the power source for the rear row of rhomboid pillars 110, causing the rear row of rhomboid pillars 110 to also vibrate violently. The vibration energy of multiple rhomboid pillars 110 can not only effectively improve the self-cleaning power, but this collective resonance can also effectively peel off the thermal boundary layer inside the spiral racetrack-shaped water tank 103, achieving regional synchronous cooling at the bend of the conical annular groove 102. Each row of rhomboid pillars 110 and the nickel-titanium protrusions 112 on their surfaces are constantly compressing the flow cross-sectional area, forming a multi-stage series Venturi effect. When the water flows through the rhomboid pillars 110, it will be squeezed and accelerated step by step, and continuously broken when repeatedly passing through the nickel-titanium protrusions 112. This not only maximizes the flow velocity at the rear, but also keeps the entire flow in a high-intensity turbulent state, pushing the heat exchange efficiency to the peak. After the cooling water flows through the bend of the conical annular groove 102, it will follow the spiral racetrack-shaped water channel 103 to the planar area of ​​the conical annular groove 102. When the cooling water comes into contact with the spiral ribs 107, the spiral ribs 107 will guide the cooling water to the inner side of the spiral racetrack-shaped water channel 103, that is, towards the steel billet. At this time, the water temperature will be significantly increased due to the heat exchange, and a large amount of scale will also be generated. After the water flows into contact with several sets of arc-shaped guide blocks 106, the water will impact the inner wall of the conical annular groove 102 under the guidance of three sets of arc-shaped guide blocks 106. Combined with the guidance generated by the spiral ribs 107, the hot liquid and cold liquid are mixed, which improves the heat dissipation effect. When the cooling water flows through the arc-shaped guide blocks 106, some of the cooling water will enter the branch channel and the main channel of the claw-shaped groove 1061. The cooling water entering the main channel, due to its wide-narrow-wide structural design, experiences a faster flow velocity upon exiting from the outlet. This high-speed water jet directly impacts the inner side of the spiral racetrack-shaped water tank 103, enhancing heat dissipation. Simultaneously, the high-speed jet possesses extremely strong shearing force, rebounding from the inner side of the spiral racetrack-shaped water tank 103. The impact of this rebound washes away scale from the surfaces of the two arc-shaped guide blocks 106, keeping both the surfaces of the arc-shaped guide blocks 106 and the interior of the spiral racetrack-shaped water tank 103 clean and preventing a decrease in thermal conductivity due to scale buildup. During the cooling water flow, it also enters through the two branch channels of the claw-shaped groove 1061. Because the section connecting to the main channel is relatively narrow, the cooling water exiting from the branch channels also possesses impact force, impacting different locations in the narrower area (throat) of the main channel to prevent scale blockage in the throat.

[0029] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0030] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A precision forming mold for large-diameter thick-walled steel pipes, comprising an extrusion cylinder (1), wherein the bottom of the extrusion cylinder (1) is provided with an annular groove, characterized in that: The extrusion cylinder (1) is provided with An annular metal insert (101) is slidably installed in an annular groove. The annular metal insert (101) is fixedly installed on the extrusion cylinder (1) by bolts. The annular metal insert (101) is thermally conductive and removable. A conical annular groove (102) is provided on the inner wall of the extrusion cylinder (1), and the conical annular groove (102) is used for forming steel billets; The cooling mechanism includes a spiral racetrack-shaped water tank (103) opened in an annular metal insert (101). A water outlet pipe (104) and a water inlet pipe (105) are fixedly installed at the bottom and top of the annular metal insert (101), respectively. A plurality of rectangular mounting slots (108) are opened in the annular metal insert (101). A two-way shape memory alloy temperature control spring (109) is installed in each of the plurality of rectangular mounting slots (108). A rhombus-shaped column (110) is slidably installed in each of the plurality of rectangular mounting slots (108). A plurality of nickel-titanium protrusions (112) are embedded on the surface of the plurality of rhombus-shaped columns (110). A flow guide slope (111) is provided on each of the plurality of rhombus-shaped columns (110).

2. The precision forming mold for large-diameter thick-walled steel pipes according to claim 1, characterized in that: The spiral racetrack-shaped water trough (103) is distributed from top to bottom. The pitch of the spiral racetrack-shaped water trough (103) gradually decreases when it is 30cm away from the bend of the conical ring groove (102). The spiral racetrack-shaped water trough (103) maintains a small pitch distribution when it is 20cm away from the bend of the conical ring groove (102). The spiral racetrack-shaped water trough (103) is distributed close to the inner diameter change direction of the conical ring groove (102).

3. The precision forming mold for large-diameter thick-walled steel pipes according to claim 1, characterized in that: The cooling mechanism also includes spiral ribs (107) fixedly installed on the inner wall of the spiral racetrack-shaped water tank (103). The spiral ribs (107) are distributed on one side near the conical annular groove (102) and are arranged along the path of the spiral racetrack-shaped water tank (103).

4. The precision forming mold for large-diameter thick-walled steel pipes according to claim 1, characterized in that: Several rectangular mounting slots (108) are symmetrically distributed, and none of the rectangular mounting slots (108) are on the same horizontal line in the transverse direction.

5. The precision forming mold for large-diameter thick-walled steel pipes according to claim 1, characterized in that: Several bidirectional shape memory alloy temperature control springs (109) are respectively disposed on the opposite side of several rectangular mounting slots (108). One end of each bidirectional shape memory alloy temperature control spring (109) is fixedly connected to the bottom inner wall of the rectangular mounting slot (108), and the other end of each bidirectional shape memory alloy temperature control spring (109) is in a free state.

6. The precision forming mold for large-diameter thick-walled steel pipes according to claim 1, characterized in that: The ends of several rhomboid pillars (110) that are far apart from each other are in contact with several two-way shape memory alloy temperature control springs (109), and the ends of several rhomboid pillars (110) that are far away from the two-way shape memory alloy temperature control springs (109) slide and extend into the spiral racetrack-shaped water tank (103).

7. The precision forming mold for large-diameter thick-walled steel pipes according to claim 1, characterized in that: Several of the nickel-titanium bumps (112) are distributed on the upper and lower surfaces of the rhomboid prism (110), and the upper and lower surfaces are triangular slopes.

8. The precision forming mold for large-diameter thick-walled steel pipes according to claim 1, characterized in that: Several of the aforementioned guide slopes (111) and several upper and lower surfaces all face the water-facing side.

9. The precision forming mold for large-diameter thick-walled steel pipes according to claim 1, characterized in that: The outlet pipe (104) and the inlet pipe (105) are both connected to the spiral racetrack-shaped water tank (103), and the spiral racetrack-shaped water tank (103) is provided with a number of arc-shaped guide blocks (106).

10. A precision forming mold for large-diameter thick-walled steel pipes according to claim 9, characterized in that: The plurality of arc-shaped guide blocks (106) are distributed in groups of three in the spiral racetrack-shaped water tank (103) on the side away from the conical annular groove (102). The plurality of arc-shaped guide blocks (106) are arranged in a triangular asymmetrical arrangement with one in the middle and two behind. Claw-shaped grooves (1061) are provided on the corresponding arc-shaped guide blocks (106) in the plurality of arc-shaped guide blocks (106). The main channel in the plurality of claw-shaped grooves (1061) is wide at both ends and narrow in the middle. The part where the water inlet end of the two branch channels in the plurality of claw-shaped grooves (1061) communicates with the branch channel is relatively narrow. The ends of the two branch channels in the plurality of claw-shaped grooves (1061) are respectively connected to different positions of the narrow part of the main channel.

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