A thixotropic bulging extrusion method and device for copper-steel composite sleeve parts

Abstract

The present invention discloses a thixotropic bulging extrusion method and device for copper-steel composite shaft sleeve parts, belonging to the field of semi-solid forming. The method described in the present invention is: cutting a preferred steel pipe and a copper pipe, removing impurities on the inner and outer surfaces of the steel pipe and the steel pipe by a lathe, and processing threads on the outer surface of the steel pipe and the inner surface of the copper pipe, and then using ultrasonic cleaning of the steel pipe and the copper pipe, and connecting the cleaned steel pipe and the copper pipe by threads. The connected steel pipe and the copper pipe are heated to between the solid and liquid phases, and then transferred to the mold, and the mold is closed to perform variable speed bulging extrusion and maintain pressure; after the mold is opened, the shaft sleeve parts are taken out and rapidly water quenched, T6 heat treatment is performed, and the parts are processed into copper-steel composite shaft sleeve parts with precise dimensions by machine tools; the method described in the present invention organically combines plastic forming technology with semi-solid forming technology, and the copper-steel interface bonding strength is high, the production efficiency is high, the energy consumption is low, the product quality is high, the material utilization rate is high, and mechanized and automated production can be realized.

Description

Technical Field

[0001] The invention relates to a thixotropic bulging extrusion method and a device for a copper-steel composite shaft sleeve part, belonging to the field of semi-solid forming. Background Art

[0002] Sleeve parts have the functions of precise guidance, precise positioning and supporting rotating shafts, and are widely used in the fields of automobiles, high-speed rail, aerospace, etc. Most traditional sleeve parts production methods use liquid forming methods such as centrifugal casting, but this method can only produce tubular blanks, and requires a large amount of subsequent cutting processing, resulting in serious material loss, low utilization rate, long production cycle and other consequences. In addition, the blanks are mostly coarse dendrites, with internal defects such as shrinkage cavities and shrinkage, resulting in low comprehensive mechanical properties of sleeve parts, affecting the service performance of parts; at the same time, after a large amount of mechanical processing, the blanks will cause a large amount of residual stress on the surface and shoulder of the sleeve parts, resulting in fracture.

[0003] With the rapid development of modern industry, the harsh service environment makes it impossible for a single metal material bushing to meet the requirements. Copper alloy bushings have good wear resistance, good thermal conductivity, and good plastic forming ability, but they have low strength, soft texture, high price, and difficult to achieve the matching precision. Steel bushings have slightly poor thermal conductivity and insufficient plastic forming ability, and are prone to wear, pitting, cracking and other failure forms, but they are low in price, high in strength, and high in processing precision. Therefore, the preparation of copper-steel composite metal bushings is expected to work stably and for a long life in complex service environments.

[0004] Since its proposal, metal semi-solid forming technology has developed rapidly; among them, thixoforming technology has the advantages of short production flow, stable production process, simple operation, low cost and high yield rate.

[0005] Conventional extrusion forming methods for preparing copper-steel composite sleeve parts have problems such as low bonding interface strength, incomplete shape, insufficient extrusion force, complicated composite process, high cost, and dangerous process, which is not conducive to the realization of mechanical automation production. Therefore, the use of thixotropic bulging extrusion method and device, a solid-semi-solid composite method to prepare copper-steel composite sleeve parts is expected to solve the problems of single material, short service life, low composite interface bonding strength, complex process, long production cycle, high cost, and low material utilization rate in the existing sleeve parts production. Summary of the invention

[0006] The purpose of the present invention is to provide a thixotropic bulging extrusion method for copper-steel composite shaft sleeve parts to solve the problems of single material, short service life, low composite interface bonding strength, incomplete shape, insufficient extrusion force, complex process, long production cycle, high cost and low material utilization rate in the existing shaft sleeve preparation method. The method utilizes semi-solid forming technology and the thixotropic bulging extrusion method to prepare copper-steel composite shaft sleeve parts with high material utilization rate, high production efficiency and excellent mechanical properties, and specifically comprises the following steps:

[0007] (1) Cut the steel pipe into sections, remove impurities on the inner and outer surfaces using a lathe, and process threads on the outer surface, and then perform ultrasonic cleaning. Remove impurities on the inner and outer surfaces of the copper pipe, and process threads on the inside, and then perform ultrasonic cleaning.

[0008] (2) Connect the copper tube and the steel tube together through threads and heat them to the semi-solid temperature of the copper tube.

[0009] (3) The mold is heated to a certain temperature by a heating coil, and the heated copper tube and steel tube connector is transferred to the preheating mold, thixotropically expanded and variable-speed extruded, and the pressure is maintained for a period of time to form a copper-steel composite sleeve part.

[0010] During the thixotropic bulging variable speed extrusion process: the upper punch moves toward the copper-steel connector at three different speeds v1, v2, and v3. The first stage is from the upper dead point of the press to the upper punch contacting the inner edge of the steel pipe. This position is set as the 0mm point and the running speed is v1. The second stage is 0-23mm and the running speed is v2. The third stage is 23-46mm and the running speed is v3. When the third stage push time reaches 6s, the speed no longer increases. Among them, v1, v2, and v3 satisfy the following relationship formula:

[0011]

[0012] Where t1 is the time taken to run at speed v1, t2 is the time taken to run at speed v2, and t3 is the time taken to run at speed v3.

[0013] (4) The upper punch is quickly moved, and the ejector cylinder drives the ejector rod to eject the copper-steel composite sleeve part. After the mold is opened, the copper-steel composite sleeve part is taken out and quickly water quenched.

[0014] (5) The composite sleeve parts after water quenching were subjected to T6 heat treatment: solution heat treatment at 660°C for 60 min and artificial aging treatment at 360°C for 120 min.

[0015] Preferably, the semi-solid temperature in step (2) of the present invention is 890-910°C.

[0016] Preferably, in step (3) of the present invention, the mold preheating temperature is 425-485°C.

[0017] The metal tube described in the present invention is a pipe fitting after plastic deformation, and can be an extruded tube, a rolled tube, a spun tube, a drawn tube, etc.

[0018] The threads processed on the outer surface of the steel tube of the present invention match well with the threads processed inside the copper tube; the steel tube and the copper tube have the same height; the upper and lower punches of the mold can produce bulging effects on the copper tube and the steel tube, and the forming parts of the upper and lower punches are completely consistent.

[0019] Another object of the present invention is to provide a variable expansion extrusion die, the die comprising an upper punch fixing plate 1, an upper punch 2, a die 5, a push rod 6, a lower punch 7, a lower punch fixing plate 8, a push rod fixing plate 9, a push plate 10, and a die fixing plate 11; the upper punch fixing plate 1 is connected to the top of the hydraulic press, the hydraulic press controls the upper punch 2 to move up and down, the upper punch 2 is fixed on the upper punch fixing plate 1, and the lower punch 7 is fixed on the lower punch fixing plate 8; when the mold is closed, the upper punch 2, the die 5, and the lower punch 7 form a cavity, and the shaft shoulder is extruded under the joint action of the upper punch 2 and the die 5, and the push rod 6 is fixed on the top plate 10 through the push rod fixing plate 9; the inner wall of the mold die 5 and the boss of the upper punch 2 are set with a draft angle of 1°; the cavity formed after the upper punch 2, the lower punch 7 and the die 5 are closed corresponds to the shape of the sleeve part.

[0020] Preferably, the upper punch fixing plate 1 of the present invention is detachably connected to the upper punch 2, and the upper punch fixing plate 1 is fixed to the top position of the hydraulic press by a T-shaped plate; the lower punch 7 is detachably connected to the lower punch fixing plate 8; the die fixing plate 11 is detachably connected to the die 5, and the die fixing plate 11 is fixed to the working table position of the hydraulic press by a T-shaped plate, and remains fixed during the extrusion process.

[0021] Preferably, the mold material of the upper punch 2, the concave mold 5, and the lower punch 7 of the present invention is H13 mold steel.

[0022] Beneficial effects of the present invention:

[0023] (1) The copper-steel composite shaft sleeve parts prepared by the present invention adopt a solid-semi-solid composite method of thixotropic bulging extrusion to effectively avoid the limitations of a single metal material shaft sleeve, give full play to the advantages of composite materials, greatly improve the strength, wear resistance, matching accuracy, and adaptability to harsh service environments of the shaft sleeve parts, while reducing production costs and increasing economic benefits.

[0024] (2) The present invention adopts a solid-semisolid composite method, which fully utilizes the excellent flowability of the semisolid metal slurry to fully fill the outer surface of the steel pipe processed into a threaded surface, effectively expel the air, and increase the bonding strength of the copper-steel composite interface. While improving the service performance, it effectively extends the service life of the copper-steel composite sleeve.

[0025] (3) The present invention adopts a thixotropic bulging extrusion method to prepare a copper-steel composite shaft sleeve. The double bulging structure enables: the copper tube externally heated to a semi-solid temperature to produce a large deformation and fully contact the external thread surface of the steel tube; the steel tube undergoes a large degree of thermoplastic deformation to produce a diameter expansion effect, and the composite is more thorough and sufficient during the downward pressure of the upper punch shoulder, and the interface bonding strength is greatly enhanced.

[0026] (4) The present invention innovates in the design of the punch and adopts a double punch design, which makes the bulging process more complete and greatly improves the interface bonding strength of the copper-steel composite layer.

[0027] (5) The mold described in the present invention is composed of a mold cavity consisting of an upper punch, a concave die, and a lower punch, so that the two metal tubes are subjected to three-dimensional compressive stress during the bulging extrusion deformation process, thereby improving the plastic deformation capacity, while increasing the organizational density of the sleeve parts and improving the comprehensive mechanical properties of the sleeve.

[0028] (6) The present invention has made innovations in the setting of the extrusion speed, adopting a variable speed extrusion method and using a slightly slower speed during the bulging process, which can make the bulging more complete and the copper-steel interface bonding layer more compact.

[0029] (7) The present invention adds a push rod to the die. After the die is closed and the bulging is performed, the push rod can be driven by the push cylinder to eject the sleeve part, and finally a copper-steel composite sleeve with complete filling and precise dimensions is obtained.

[0030] (8) Compared with conventional liquid forming, the composite sleeve parts prepared by the present invention have the advantages that the internal structure of the copper layer is a semi-solid structure with uniformly distributed spherical or near-spherical solid particles and dispersed liquid phase, and has good comprehensive mechanical properties. During the forming process, the structure is more compact due to the extrusion force, and it is a near-net shape with high material utilization. In addition, the layered composite process cannot be achieved by liquid forming. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the die structure of the thixotropic bulging extrusion die opening of the present invention;

[0032] Figure 2 It is a schematic diagram of the die structure of the intermediate process of thixotropic bulging extrusion of the present invention;

[0033] Figure 3 It is a schematic diagram of the mold structure of the thixotropic bulging extrusion mold clamping according to the present invention.

[0034] Figure 3 Middle: 1-upper punch fixing plate; 2-upper punch; 3-steel pipe; 4-copper pipe; 5-die; 6-elevator rod; 7-lower punch; 8-lower punch fixing plate; 9-elevator rod fixing plate; 10-elevator plate; 11-die fixing plate. DETAILED DESCRIPTION

[0035] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited to the contents described above.

[0036] The mold structure used in the embodiment of the present invention is as follows Figures 1 to 3 As shown, it includes an upper punch fixing plate 1, an upper punch 2, a steel pipe 3, a copper pipe 4, a die 5, a push rod 6, a lower punch 7, a lower punch fixing plate 8, a push rod fixing plate 9, a push plate 10, and a die fixing plate 11; the upper punch fixing plate 1 is connected to the top of the hydraulic press, and the hydraulic press controls the upper punch 2 to move up and down; when the mold is in the mold opening state, the push cylinder is in the ejection state, and the push rod 6, the lower punch 7, the lower punch fixing plate 8, the push rod fixing plate 9, and the push plate 10 are all in the ejection state; the upper punch 2 moves downward Until it contacts with the lower punch 7, after contact, the upper punch 2 presses down the lower punch 7 to complete the extrusion bulging process during the movement of the upper and lower punches; when the mold is closed, the upper punch 2, the die 5, and the lower punch 7 form a cavity, and the shaft shoulder is extruded under the joint action of the upper punch 2 and the die 5. When the mold is opened, the top cylinder is pushed out and the push rod 10 pushes out the sleeve; the inner wall of the mold die 5 and the boss of the upper punch 2 are set with a draft angle of 1°; the cavity formed after the upper punch 2, the lower punch 7 and the die 5 are closed corresponds to the shape of the sleeve part.

[0037] In this embodiment, the upper punch fixing plate 1 is bolted to the upper punch 2, and the upper punch fixing plate 1 is fixed to the top position of the hydraulic press through a T-plate; the lower punch is bolted to the lower punch fixing plate 8; the die fixing plate 11 is bolted to the die 5, and the die fixing plate 11 is fixed to the working table position of the hydraulic press through a T-plate and remains fixed during the extrusion process; the mold materials of the upper punch 2, the die 5, and the lower punch 7 are H13 mold steel.

[0038] The use process of the mold described in the present invention is as follows: before the shaft sleeve part is extruded and formed, the hydraulic press controls the upper punch 2 to retreat to the top of the hydraulic press; the graphite release agent is sprayed on the surfaces of the upper punch 2, the die 5 and the lower punch 7; the mold is preheated to 425-485°C; the heated steel pipe 3 and copper pipe 4 assembly are placed in the die 5; the hydraulic press is driven to make the upper punch 2 move vertically downward, so that the upper punch 2 and the die 5 are closed, and bulging extrusion is performed, and the pressure is maintained for 29 seconds; the top cylinder is pushed out when the mold is opened; the shaft sleeve part is taken out and quickly quenched in water, and finally T6 heat treatment is performed; during the entire bulging and extrusion forming process, the mold is easy to operate, mechanized production can be realized, and energy is saved, and the composite shaft sleeve part finally obtained has uniform organizational properties, high bonding strength of the copper-steel composite layer, and excellent comprehensive mechanical properties.

[0039] Example 1

[0040] The present embodiment describes a thixotropic bulging extrusion method for a copper-steel composite sleeve part, such as Figure 1 As shown, the specific steps are as follows:

[0041] (1) The copper alloy material of this embodiment is ZCuSn10P1. The solidus temperature of the ZCuSn10P1 copper alloy is measured to be 876.1°C, and the liquidus temperature is 1024.2°C. The steel material is 45# steel.

[0042] (2) A steel tube with an inner diameter of 26 mm, an outer diameter of 36 mm, and a height of 46 mm was cleaned by ultrasonic wave after removing impurities from its outer surface and processing threads; a copper tube with an inner diameter of 36 mm, an outer diameter of 46 mm, and a height of 46 mm was cleaned by ultrasonic wave after removing impurities from its inner surface and processing threads or spiral tracks matching the outer surface of the steel tube. The copper tube and the steel tube were connected together by threads and heated in a box-type resistance furnace to the semi-solid temperature of the copper tube of 890°C.

[0043] (3) The mold is preheated to 425°C by an induction coil, and the steel tube-copper tube assembly heated to 890°C is placed in the die.

[0044] (4) The die is driven to close at the bulging extrusion speed shown in Table 1, and the pressure is maintained for 26 seconds after the bulging extrusion is completed.

[0045] Table 1

[0046]

[0047] (5) The upper punch is quickly moved, and the ejector cylinder drives the ejector rod to eject the copper-steel composite sleeve part. After the mold is opened, the copper-steel composite sleeve part is taken out, and the sleeve part after thixotropic expansion extrusion is quickly water quenched, solution heat treated at 660°C for 60 minutes, artificial aging treated at 360°C for 120 minutes, and then air-cooled to room temperature.

[0048] The copper-steel composite sleeve part prepared in this embodiment has a smooth surface, precise size, high composite layer bonding strength, a tensile strength of 727 MPa, an interface bonding strength of 152 MPa, and good mechanical properties.

[0049] Comparative Example 1

[0050] All steps of this embodiment are the same as those of Embodiment 1, except that in step (4), conventional thixotropic extrusion is used to prepare the copper-steel composite bushing, and the prepared part has a tensile strength of 672 MPa and an interface bonding strength of 121 MPa.

[0051] The specific extrusion process of conventional thixotropic extrusion is as follows: using the forward extrusion method, the cylindrical single punch moves downward at a constant speed of 16 mm / s, and the mold is closed and the pressure is maintained for 26 seconds.

[0052] By comparison, it can be seen that the mechanical properties of the sleeve parts made by thixotropic bulging extrusion are better.

[0053] Example 2

[0054] The present embodiment describes a thixotropic bulging extrusion method for a copper-steel composite sleeve part, such as Figure 1 As shown, the specific steps are as follows:

[0055] (1) The copper alloy material of this embodiment is ZCuSn10P1. The solidus temperature of the ZCuSn10P1 copper alloy is measured to be 876.1°C and the liquidus temperature is 1024.2°C. The steel material is 20CrMoTi.

[0056] (2) A steel tube with an inner diameter of 26 mm, an outer diameter of 36 mm, and a height of 46 mm was cleaned by ultrasonic wave after removing impurities from its outer surface and processing threads; a copper tube with an inner diameter of 36 mm, an outer diameter of 46 mm, and a height of 46 mm was cleaned by ultrasonic wave after removing impurities from its inner surface and processing threads matching the outer surface of the steel tube. The copper tube and the steel tube were connected together by threads and heated in a box-type resistance furnace to the semi-solid temperature of the copper tube at 900°C.

[0057] (3) The mold is preheated to 465°C by an induction coil, and the steel tube-copper tube assembly heated to 900°C is placed in the die.

[0058] (4) The die is driven to close at the bulging extrusion speed shown in Table 2, and the pressure is maintained for 29 seconds after the bulging extrusion is completed.

[0059] Table 2

[0060]

[0061] (5) The upper punch is quickly moved, and the ejector cylinder drives the ejector rod to eject the copper-steel composite sleeve part. After the mold is opened, the copper-steel composite sleeve part is taken out, and the sleeve part after thixotropic expansion extrusion is quickly water quenched, solution heat treated at 660°C for 60 minutes, artificial aging treated at 360°C for 120 minutes, and then air-cooled to room temperature.

[0062] The copper-steel composite sleeve part prepared in this embodiment has a smooth surface, precise size, high composite layer bonding strength, a tensile strength of 918.4 MPa, an interface bonding strength of 204 MPa, and good mechanical properties.

[0063] Comparative Example 2

[0064] All steps of this embodiment are the same as those of Embodiment 2, except that in step (4), the copper-steel composite bushing is prepared by conventional thixotropic extrusion, and the prepared part has a tensile strength of 870.2 MPa and an interface bonding strength of 150 MPa.

[0065] The specific extrusion process of conventional thixotropic extrusion is as follows: using the forward extrusion method, the cylindrical single punch moves downward at a constant speed of 16 mm / s, and the mold is closed and the pressure is maintained for 29 seconds.

[0066] By comparison, it can be seen that the mechanical properties of the sleeve parts made by thixotropic bulging extrusion are better.

[0067] Example 3

[0068] The present embodiment describes a thixotropic bulging extrusion method for a copper-steel composite sleeve part, such as Figure 1 As shown, the specific steps are as follows:

[0069] (1) The copper alloy material of this embodiment is ZCuSn10P1. The solidus temperature of the ZCuSn10P1 copper alloy is measured to be 876.1°C, and the liquidus temperature is 1024.2°C. The steel material is bearing steel GCr15.

[0070] (2) A steel tube with an inner diameter of 26 mm, an outer diameter of 36 mm, and a height of 46 mm was cleaned by ultrasonic wave after removing impurities from its outer surface and processing threads; a copper tube with an inner diameter of 36 mm, an outer diameter of 46 mm, and a height of 46 mm was cleaned by ultrasonic wave at 900°C after removing impurities from its inner surface and processing threads matching the outer surface of the steel tube. The copper tube and the steel tube were connected together by threads and heated in a box-type resistance furnace to the semi-solid temperature of the copper tube at 910°C.

[0071] (3) The mold is preheated to 485°C by an induction coil, and the steel tube-copper tube assembly heated to 910°C is placed in the die.

[0072] (4) The die is driven to close at the bulging extrusion speed shown in Table 3, and the pressure is maintained for 32 seconds after the bulging extrusion is completed.

[0073] Table 3

[0074]

[0075] (5) The upper punch is quickly moved, and the ejector cylinder drives the ejector rod to eject the copper-steel composite sleeve part. After the mold is opened, the copper-steel composite sleeve part is taken out, and the sleeve part after thixotropic expansion extrusion is quickly water quenched, solution heat treated at 660°C for 60 minutes, artificial aging treated at 360°C for 120 minutes, and then air-cooled to room temperature.

[0076] The copper-steel composite sleeve part prepared in this embodiment has a smooth surface, precise size, high composite layer bonding strength, a tensile strength of 790.8 MPa, an interface bonding strength of 178 MPa, and good mechanical properties.

[0077] Comparative Example 3

[0078] All steps of this embodiment are the same as those of Embodiment 3, except that in step (4), the copper-steel composite bushing is prepared by conventional thixotropic extrusion, and the prepared part has a tensile strength of 740.3 MPa and an interface bonding strength of 134 MPa.

[0079] The specific extrusion process of conventional thixotropic extrusion is as follows: using the forward extrusion method, the cylindrical single punch moves downward at a constant speed of 16 mm / s, and the mold is closed and the pressure is maintained for 32 seconds.

[0080] By comparison, it can be seen that the mechanical properties of the sleeve parts made by thixotropic bulging extrusion are better.

Claims

1. A thixotropic bulging extrusion method for copper-steel composite sleeve parts, characterized in that: The specific steps include: (1) Cut the steel pipe into sections, remove impurities on the inner and outer surfaces using a lathe, and process threads on the outer surface, and then perform ultrasonic cleaning; remove impurities on the inner and outer surfaces of the copper pipe, and process threads on the inside, and then perform ultrasonic cleaning; (2) Connecting the copper tube and the steel tube together by threads and heating them to the semi-solid temperature of the copper tube; (3) The mold is heated to a certain temperature by a heating coil, and the heated copper tube and steel tube connector is transferred to the preheating mold, thixotropically expanded and extruded at a variable speed, and the pressure is maintained for a period of time to form a copper-steel composite sleeve part; During the thixotropic bulging variable speed extrusion process, the upper punch moves toward the copper-steel connector at three different speeds v1, v2, and v3. The first stage is from the upper dead point of the press to the upper punch contacting the inner edge of the steel pipe. This position is set as the 0mm point and the running speed is v1. The second stage is 0-23mm and the running speed is v2. The third stage is 23-46mm and the running speed is v3. When the third stage push time reaches 6s, the speed no longer increases. Among them, v1, v2, and v3 satisfy the following relationship formula: Where t1 is the time taken to run at speed v1, t2 is the time taken to run at speed v2, and t3 is the time taken to run at speed v3; The unit of v1, v2, v3 is mm / s, and the unit of t1, t2, t3 is s; (4) The upper punch is quickly moved, and the ejector cylinder drives the ejector rod to eject the copper-steel composite sleeve part. After the mold is opened, the copper-steel composite sleeve part is taken out and quickly water quenched; (5) Perform T6 heat treatment on the composite sleeve parts after water quenching; The mold in step (3) comprises an upper punch fixing plate (1), an upper punch (2), a die (5), a push rod (6), a lower punch (7), a lower punch fixing plate (8), a push rod fixing plate (9), a push plate (10), and a die fixing plate (11); the upper punch fixing plate (1) is connected to the top of a hydraulic press, and the hydraulic press controls the upper punch (2) to move up and down, the upper punch (2) is fixed on the upper punch fixing plate (1), and the lower punch (7) is fixed on the lower punch fixing plate (8). The upper punch (2), the concave die (5) and the lower punch (7) form a cavity when the mold is closed, and a shaft shoulder is extruded under the joint action of the upper punch (2) and the concave die (5). The ejector rod (6) is fixed on the ejector plate (10) through the ejector rod fixing plate (9); the inner wall of the mold concave die (5) and the boss of the upper punch (2) are set with a draft angle of 1°; the cavity formed after the upper punch (2), the lower punch (7) and the concave die (5) are closed corresponds to the shape of the shaft sleeve part.

2. The thixotropic bulging extrusion method for copper-steel composite sleeve parts according to claim 1 is characterized in that: The semi-solid temperature in step (2) is 890-910°C.

3. The thixotropic bulging extrusion method for copper-steel composite sleeve parts according to claim 2 is characterized in that: In step (3), the mold preheating temperature is 425-485°C.

4. The thixotropic bulging extrusion method for copper-steel composite sleeve parts according to claim 3 is characterized in that: The specific process of T6 heat treatment is: solution heat treatment at 660℃ for 60min and artificial aging treatment at 360℃ for 120min.

5. The thixotropic bulging extrusion method for copper-steel composite sleeve parts according to claim 1 is characterized in that: The upper punch fixing plate (1) is detachably connected to the upper punch (2), and the upper punch fixing plate (1) is fixed to the top of the hydraulic press via a T-shaped plate; the lower punch (7) is detachably connected to the lower punch fixing plate (8); the die fixing plate (11) is detachably connected to the die (5), and the die fixing plate (11) is fixed to the working table of the hydraulic press via a T-shaped plate and remains fixed during the extrusion process.

6. The thixotropic bulging extrusion method for copper-steel composite sleeve parts according to claim 1 is characterized in that: The upper punch (2), the concave die (5) and the lower punch (7) are made of H13 die steel.

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