A Bimetal Composite Manufacturing Method for a Self-Lubricating Extrusion Die

Abstract

The present invention provides a method for manufacturing a bimetallic combination of a self-lubricating extrusion die. The upper die head insert and the lower die cavity insert are made of eutectic graphite steel, while the other parts of the upper die and the lower die are made of H13 steel. The eutectic graphite steel consists of the following elements: C: 3.62 - 3.7 wt%, Si: 2.3 - 2.56 wt%, Ni: 6.5 - 8.2 wt%, W: 1.0 - 3.0 wt%, Mo: 1.0 - 2.0 wt%, V: 0.5 - 1.5 wt%, Cr: 0.5 - 1.5 wt%, Al: 0.7 - 1.6 wt%, Mg: 0.03 - 0.04 wt%, and the balance is Fe. The eutectic graphite steel is prepared by either die casting or continuous casting. The number of eutectic cell graphite balls in the profile is between 300 pieces / mm<supgt;2< / supgt> - 500 pieces / mm<supgt;2< / supgt>, and the graphite volume fraction is greater than 6%. The present invention uses wear-resistant and interchangeable self-lubricating eutectic graphite steel inserts with a small friction coefficient and high hardness, thereby prolonging the overall life of the die, significantly reducing the die consumption cost in the extrusion forming of aluminum and magnesium alloys, and ultimately reducing the production cost of aluminum and magnesium alloys.

Description

Technical Field

[0001] The present invention belongs to the technical field of extrusion forming of aluminum and magnesium alloy profiles, and particularly relates to a bimetal combination manufacturing method for a self-lubricating extrusion die. Background Art

[0002] At present, the 4Cr5MoV series hot work die steel (also known as H13 die steel) used in the aluminum and magnesium alloy profile extrusion industry can meet the high-temperature strength and toughness requirements for extrusion at 500°C - 550°C. However, due to the aluminothermic reaction, hard particles such as aluminum oxide and aluminum-iron compounds are generated and adhered to the cavity wall of the extrusion channel, increasing the friction coefficient between the aluminum material and the extrusion joint surface of the die. Moreover, under the hot wear of the extruded aluminum material at a speed of more than 10 meters per second and a friction and wear temperature greater than 500°C, the hardness of the extrusion channel of the H13 steel die cavity obtained only by quenching and high-temperature tempering to about 50 HRC is not durable enough to maintain the unilateral wear of the extrusion channel less than 30 microns within a 3-hour profile extrusion cycle. Therefore, every 1 - 2 hours of extrusion on the production line, the die needs to be removed, the inner cavity cleaned, and then carbonitriding treatment lasting 8 - 10 hours is carried out for the purpose of increasing the surface hardness. Even so, since the extrusion channel always wears after each nitriding of the extruded profile, after 6 - 8 cycles of an extrusion die, about 8 - 10 tons of extruded profiles, and a cumulative service time of about 20 hours, the die will be scrapped due to the out-of-tolerance of the extrusion channel size. Summary of the Invention

[0003] Analysis of the force characteristics and failure mechanism of the die shows that although the "diversion channel" on the upper die of the extrusion die bears the powerful extrusion force of dividing an aluminum rod into four or even six parts, the "diversion channel" has little impact on the accuracy of the profile section structure. Because the dimensional accuracy of the extruded profile is completely determined by the "profile extrusion channel" formed by the "worker head" on the upper die being embedded in the "die cavity" of the lower die. As long as the wear resistance of the four cylindrical surfaces of the "worker head" on the upper die and the "inner wall of the die cavity" of the lower die for the extrusion of 500°C aluminum material is improved, the service life of the die can be extended, and even the increase in usage cost and the increase in the number of spare sets caused by periodic nitriding can be avoided.

[0004] To reduce the wear rate of the four cylindrical surfaces of the "worker head" and the "inner wall of the die cavity" during the extrusion of 500°C aluminum material, its material should have the following properties: (1) It has the characteristic of reducing the adhesion of hard particles such as aluminum oxide and aluminum-iron compounds caused by the aluminothermic reaction to the die cavity, thereby reducing the friction coefficient of the joint surface during the extrusion of the aluminum material to reduce the die cavity wear rate; (2) On the premise of a low friction coefficient, if it further has a high-temperature hardness not lower than that of the nitrided layer, the wear rate of the extruded aluminum material will be significantly reduced.

[0005] Combined with the analysis of the stress state and failure mechanism of the extrusion die, and based on the following materials science principles: (1) During the liquid-solid transformation of the iron-carbon system melt, the small-spacing graphite balls precipitated can spread along the bonding surface under the action of the tangential force in the extrusion channel to form a self-lubricating graphite film, thereby inhibiting the adhesion between aluminum and iron and playing a self-lubricating role; (2) The graphite carbon embedded in the matrix can dissolve in the matrix at a high concentration during high-temperature austenitization. During quenching and high-temperature tempering, it combines with carbide-forming elements such as chromium, tungsten, molybdenum, and vanadium to precipitate dispersedly, thereby increasing the hardness of the matrix.

[0006] Based on this, the present invention provides a eutectic graphite steel containing alloy elements such as nickel, chromium, tungsten, molybdenum, vanadium, and aluminum, with a tempering hardness at 600 °C greater than the hardness of the nitrided layer (above HRC58), to manufacture the upper die "tool head" and the lower die "die cavity", which are embedded in a high-strength and tough H13 die body to form a self-lubricating bimetallic extrusion die composed of the H13 die body and the eutectic graphite steel.

[0007] A self-lubricating bimetallic extrusion die, in which the upper die tool head insert and the lower die inner cavity insert are made of eutectic graphite steel, and the other parts of the upper die and the lower die are made of H13 steel;

[0008] The eutectic graphite steel is composed of the following elements: C: 3.62 - 3.7 wt%, Si: 2.3 - 2.56 wt%, Ni: 6.5 - 8.2 wt%, W: 1.0 - 3.0 wt%, Mo: 1.0 - 2.0 wt%, V: 0.5 - 1.5 wt%, Cr: 0.5 - 1.5 wt%, Al: 0.7 - 1.6 wt%, Mg: 0.03 - 0.04 wt%, and the balance is Fe;

[0009] A bimetallic combination manufacturing method for a self-lubricating extrusion die, and the specific steps include:

[0010] Step 1: According to the composition requirements of the eutectic graphite steel, calculate the percentage contents of the raw materials slab iron or blast furnace hot metal, scrap steel, pure Ni plate, ferrotungsten, ferromolybdenum, ferrovanadium, ferrochromium, aluminum block, inoculant, and spheroidizing agent, and weigh the dosages of each raw material according to the calculated percentages of each raw material and the specific weight of the hot metal to be melted and prepared.

[0011] Step 2: Melt the raw materials weighed in Step 1 into hot metal in an induction furnace;

[0012] Step 3: Cast the hot metal melted in Step 2 into profiles of the upper die tool head insert or the lower die inner cavity insert;

[0013] Step 4: Perform stress relief annealing treatment on the profiles of the upper die tool head insert or the lower die inner cavity insert cast in Step 3;

[0014] Step 5: Perform solution treatment and composition homogenization annealing on the stress-relieved annealed upper die head insert or lower die insert profile.

[0015] Step 6: Cut the upper die head insert or lower die cavity insert profile by wire cutting, and machine it into the part blank of the upper die head insert or lower die cavity insert by machining.

[0016] Step 7: Perform heat treatment tempering on the machined part blank of the upper die head insert or lower die insert.

[0017] Step 8: Finish machining the part blank of the upper die head and lower die insert after final heat treatment by grinding.

[0018] Step 9: Inlay the machined lower die cavity insert into the machined lower die seat, inlay the machined upper die head into the machined upper die seat, and then close the lower die and the upper die to obtain a complete aluminum and magnesium alloy extrusion die assembled together.

[0019] Further, the melting temperature of the molten iron in Step 2 is 1530 - 1550 °C.

[0020] Further, the casting temperature of the molten iron in Step 3 is 1410 - 1430 °C.

[0021] Further, the number of graphite balls in the profile obtained in Step 3 is between 300 pieces / mm 2 ~500 pieces / mm 2 and the graphite volume fraction is greater than 6%; the shape of the profile is circular and square.

[0022] Further, the stress-relieving annealing temperature in Step 4 is: 550 - 600 °C, and the holding time is 3 h - 5 h.

[0023] Further, the solution treatment and composition homogenization annealing process in Step 5 is:

[0024] The solution and composition homogenization are carried out simultaneously, and the treatment process is 1000 - 1100 °C, holding for 9 h - 12 h; after solution treatment, it is cooled in the furnace to 750 - 800 °C, holding for 2 h - 3 h; then it is furnace-cooled to 620 - 670 °C, holding for 6 h - 8 h; after completion, it is taken out of the furnace and air-cooled to room temperature.

[0025] Further, the solution treatment and composition homogenization annealing process are carried out under a protective atmosphere or vacuum condition.

[0026] Further, the outer cylindrical surface of the lower die cavity insert and its mating inner surface of the lower die are both machined with a taper of 1° - 3°.

[0027] Further, the heat treatment and tempering process in Step 7 is as follows:

[0028] Keep it at 1000 - 1050 °C for 1 h, then water-cool, and then keep it at 500 - 600 °C for 1 h and then furnace-cool. The furnace-cooling after keeping it at 500 - 600 °C for 1 h can be repeated 2 - 3 times.

[0029] Another process is: keep it at 880 - 950 °C for 1 h and then furnace-cool to 600 °C and take it out of the furnace for air-cooling, and then temper at 500 °C for 1 h; among them, the heating process is carried out in an atmosphere furnace or a vacuum furnace.

[0030] Advantages of the present invention:

[0031] A bimetallic combination manufacturing method of a self-lubricating extrusion die provided by the present invention uses self-lubricating eutectic graphite steel inserts with small friction coefficient, high hardness, wear resistance and interchangeability for the easily worn parts - the upper die head and the lower die cavity in the aluminum and magnesium alloy extrusion die, which cause the entire die to fail due to wear. Thus, the overall life of the die is prolonged, the die consumption cost in the aluminum and magnesium alloy extrusion molding manufacturing is significantly reduced, and finally the production cost of the aluminum and magnesium alloy is reduced. Description of the Drawings

[0032] The drawings generally illustrate various embodiments by way of example rather than limitation, and are used together with the description and the claims to explain the embodiments of the invention. Where appropriate, the same reference numerals are used throughout the drawings to refer to the same or similar parts. Such embodiments are illustrative and are not intended to be an exhaustive or exclusive embodiment of the device or method.

[0033] Figure 1 Shows the upper and lower dies of the extrusion die of the present invention;

[0034] Figure 2 Shows the profile extrusion channel structure of the present invention;

[0035] Figure 3 Shows the combination method of the bimetallic combination of the extrusion die of the present invention;

[0036] Figure 4 Shows the lower die cavity of the present invention and its inlay structure diagram in the lower die;

[0037] Figure 5 Shows the upper die head of the present invention and its inlay structure diagram in the upper die;

[0038] Figure 6 Shows the upper and lower die clamping structure diagram of the present invention;

[0039] Figure 7 Shows the metallographic structure diagram of the profile after heat treatment of the present invention;

[0040] Among them, 1 is the connecting screw between the inner cavity insert and the lower mold; 2 is the locating pin for the upper and lower molds; 3 is the connecting screw between the foreman insert and the upper mold; 4 is the locating pin between the foreman insert and the upper mold. DETAILED DESCRIPTION

[0041] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0042] Example 1

[0043] Step 1: Ingredients. According to the composition requirements of eutectic graphite steel, calculate the percentage of raw materials such as bread iron or blast furnace iron, scrap steel, pure Ni plate, ferrotungsten, ferromolybdenum, ferrovanadium, ferrochrome, aluminum block, inoculant, and spheroidizer, and weigh the amount of each raw material according to the calculated percentage of each raw material and the specific weight of molten iron;

[0044] Step 2: Raw material smelting. The weighed raw materials are heated to 1530℃ in an induction furnace to melt into molten iron;

[0045] Step 3: Casting. The smelted molten iron is inoculated in a ladle. The temperature of the treated molten iron is 1430°C. Then it is formed into a profile of an upper mold head or a lower mold insert according to the process requirements and steps of horizontal continuous casting or mold casting. The composition of the profile after casting is: C: 3.7wt%, Si: 2.56wt%, Ni: 8.2wt%, W: 3.0wt%, Mo: 2.0wt%, V: 1.5wt%, Cr: 1.5wt%, Al: 1.6wt%, Mg: 0.04wt%, and the remainder is Fe. The structure of the profile is: the number of graphite balls is 300-500 / mm 2 , the graphite volume fraction is 8%.

[0046] Step 4: Stress relief annealing of castings. The cast upper die head or lower die insert is subjected to stress relief annealing at 600℃ for 5 hours;

[0047] Step 5: Solution treatment and homogenization annealing. The upper die head or lower die insert profile after stress relief annealing is solution treated and homogenized. The solution treatment and homogenization annealing process is: 1100℃ for 12h. After solution treatment, it is cooled to 800℃ and kept for 3h, and then cooled to 670℃ for 8h. After the end, it is taken out of the furnace and air-cooled to room temperature. Solution treatment and homogenization annealing are carried out in a protective atmosphere or vacuum conditions. After solution treatment and homogenization annealing, the hardness of the profile is HRC34, and the structure is troostite + fine spherical graphite.

[0048] Step 6: Machining the upper die foreman or lower die insert profile into a blank. Cut the upper die foreman or lower die insert profile by wire cutting and machine it into the part blank of the upper die foreman or lower die insert. The outer cylindrical surface of the inner cavity insert and the mating inner surface of the lower die are both machined with a 3° taper to facilitate the loading and unloading of the inner cavity insert and to accommodate the change in assembly tolerance caused by the inconsistent thermal matching between the insert and the lower die material.

[0049] Step 7: Final heat treatment conditioning of the upper die foreman and lower die insert part blanks. Adjust the mechanical properties and microstructure of the machined upper die foreman or lower die insert part blanks through quenching + tempering to meet the mechanical property requirements of aluminum and magnesium alloy extrusion dies. There are two heat treatment conditioning processes. One process is: heat preservation at 1050°C for 1 h, then water cooling, and then heat preservation at 600°C for 1 h followed by furnace cooling, where the furnace cooling after heat preservation at 600°C can be repeated 2 - 3 times. Another process is: heat preservation at 950°C for 1 h followed by furnace cooling to 600°C and then air cooling upon furnace discharge, and then tempering at 500°C for 1 h. The heating is carried out in an atmosphere furnace or a vacuum furnace, and the hardness of the heat-treated parts is HRC61. The metallographic structure of the heat-treated material is tempered martensite + a small amount of carbides.

[0050] Step 8: Finish machining of the upper die foreman and lower die insert part blanks after heat treatment. Finish machine the upper die foreman and lower die insert part blanks after final heat treatment by grinding to meet the dimensional and precision requirements of the die.

[0051] Step 9: Assembly. Fit the machined lower die insert and upper die foreman into the machined H13 lower die base and upper die base respectively, then close the lower die and the upper die, and obtain a complete aluminum and magnesium alloy extrusion die assembled together.

[0052] Example 2

[0053] Step 1: Batching. According to the composition requirements of eutectic graphite steel, calculate the percentage contents of raw materials such as pig iron or blast furnace hot metal, scrap steel, pure Ni plate, ferrotungsten, ferromolybdenum, ferrovanadium, ferrochrome, aluminum block, inoculant, and spheroidizing agent, and weigh the dosages of each raw material according to the calculated percentage of each raw material and the specific weight of the hot metal to be melted and prepared.

[0054] Step 2: Melting of raw materials. Heat the weighed raw materials in an induction furnace to 1530°C to melt them into hot metal.

[0055] Step 3: Casting. The molten iron is inoculated in a ladle. The temperature of the treated molten iron is 1410 °C, and then it is formed into profiles of the upper die boss or the lower die insert according to the process requirements and steps of horizontal continuous casting or die casting. The composition of the profile after casting is: C: 3.62 wt%, Si: 2.3 wt%, Ni: 6.5 wt%, W: 1.0 wt%, Mo: 1.0 wt%, V: 0.5 wt%, Cr: 0.5 wt%, Al: 0.7 wt%, Mg: 0.03 wt%, and the balance is Fe. The structure of the profile is: the number of eutectic graphite balls is 300 - 400 per mm 2 , and the graphite volume fraction is 6.5%.

[0056] Step 4: Stress relief annealing of the casting. The profiles of the upper die boss or the lower die insert formed by casting are subjected to stress relief annealing at 550 °C for 3 h;

[0057] Step 5: Solution treatment and composition homogenization annealing. The profiles of the upper die boss or the lower die insert after stress relief annealing are subjected to solution treatment and composition homogenization annealing. The solution treatment and composition homogenization annealing process is: holding at 1000 °C for 9 h. After solution treatment, it is cooled in the furnace to 750 °C and held for 2 h, then furnace cooled to 620 °C and held for 6 h. After completion, it is taken out of the furnace and air cooled to room temperature. The solution treatment and composition homogenization annealing are carried out under a protective atmosphere or in a vacuum. After solution treatment and composition homogenization annealing, the hardness of the profile is HRC28, and the structure is sorbite + fine spherical graphite.

[0058] Step 6: Machining of the upper die boss or lower die insert profile into a blank. The profiles of the upper die boss or the lower die insert are cut by wire cutting and machined into blank parts of the upper die boss or the lower die insert. The outer cylindrical surface of the inner cavity insert and its mating inner surface of the lower die are both machined with a 1° taper to facilitate the loading and unloading of the inner cavity insert and to adapt to the change in assembly tolerance caused by the inconsistent thermal matching between the insert and the lower die material.

[0059] Step 7: Final heat treatment tempering of the upper die boss and lower die insert blank parts. The blank parts of the upper die boss or the lower die insert after machining are quenched + tempered to adjust the mechanical properties and structure of the parts to meet the mechanical property requirements of aluminum and magnesium alloy extrusion dies. There are two heat treatment tempering processes. One process is: holding at 1000 °C for 1 h, then water cooling, and then holding at 500 °C for 1 h and furnace cooling, and the furnace cooling after holding at 500 °C for 1 h can be repeated 2 - 3 times. Another process is: holding at 880 °C for 1 h and then furnace cooling to 600 °C and taking out of the furnace for air cooling, and then tempering at 500 °C for 1 h. The heating is carried out in an atmosphere furnace or a vacuum furnace, and the hardness of the parts after heat treatment is HRC57. The metallographic structure of the heat treatment material is tempered martensite + a small amount of carbides.

[0060] Step 8: Finish machining of the rough blanks of the upper die head and the lower die insert after heat treatment. Finish machine the rough blanks of the upper die head and the lower die insert after final heat treatment by grinding to meet the dimensional and precision requirements of the die.

[0061] Step 9: Assembly. Distribute and inlay the machined lower die insert and the upper die head into the machined H13 lower die base and upper die base, then close the lower die and the upper die, and obtain a complete aluminum and magnesium alloy extrusion die assembled together.

[0062] Example 3

[0063] Step 1: Batching. According to the composition requirements of eutectic graphite steel, calculate the percentage contents of raw materials such as pig iron or blast furnace hot metal, scrap steel, pure Ni plate, ferrotungsten, ferromolybdenum, ferrovanadium, ferrochrome, aluminum block, inoculant, and spheroidizing agent, and weigh the dosages of each raw material according to the calculated percentage of each raw material and the specific weight of the molten iron to be melted and prepared.

[0064] Step 2: Melting of raw materials. Heat the weighed raw materials in an induction furnace to 1540 °C to melt them into molten iron.

[0065] Step 3: Casting and forming. Conduct inoculation treatment on the molten iron in a ladle, and the temperature of the molten iron after treatment is 1420 °C. Then, form it into the profiles of the upper die head or the lower die insert according to the process requirements and steps of horizontal continuous casting or die casting. The composition of the profile after casting is: C: 3.65 wt%, Si: 2.40 wt%, Ni: 7.50 wt%, W: 2.0 wt%, Mo: 1.5 wt%, V: 1.0 wt%, Cr: 1.0 wt%, Al: 1.0 wt%, Mg: 0.035 wt%, and the balance is Fe. The structure of the profile is: the number of eutectic graphite balls is 400 - 500 per mm 2 , and the graphite volume fraction is 6.9%.

[0066] Step 4: Stress relief annealing of the casting. Conduct stress relief annealing treatment on the profiles of the upper die head or the lower die insert formed by casting at 580 °C for 4 h.

[0067] Step 5: Solution treatment and homogenization annealing of composition. Conduct solution treatment and homogenization annealing of composition on the profiles of the upper die head or the lower die insert after stress relief annealing. The solution treatment and homogenization annealing process is: hold at 1050 °C for 10 h. After solution treatment, cool with the furnace to 780 °C and hold for 2.5 h, then cool in the furnace to 650 °C and hold for 7 h. After that, take it out of the furnace and air cool to room temperature. The solution treatment and homogenization annealing of composition are carried out under a protective atmosphere or in a vacuum. After the solution treatment and homogenization annealing of composition, the hardness of the profile is HRC30, and the structure is sorbite + fine spherical graphite.

[0068] Step 6: Machining the upper die foreman or the lower die insert profile into a blank. Cut the upper die foreman or the lower die insert profile by wire cutting and machine it into the part blank of the upper die foreman or the lower die insert. The outer cylindrical surface of the inner cavity insert and the inner surface of the lower die that mates with it are both machined with a 2° taper to facilitate the loading and unloading of the inner cavity insert and to accommodate the change in assembly tolerance caused by the inconsistent thermal matching between the insert and the lower die material.

[0069] Step 7: Final heat treatment tempering of the upper die foreman and the lower die insert part blanks. Quench + temper the machined upper die foreman or lower die insert part blanks to adjust the mechanical properties and microstructure of the parts to meet the mechanical property requirements of aluminum and magnesium alloy extrusion dies. There are two heat treatment tempering processes. One process is: keep at 1030 °C for 1 h, then water cool, and then keep at 550 °C for 1 h and furnace cool. The furnace cooling at 550 °C for 1 h can be repeated 2 - 3 times. Another process is: keep at 900 °C for 1 h and furnace cool to 600 °C and then air cool out of the furnace, and then temper at 500 °C for 1 h. The heating is carried out in an atmosphere furnace or a vacuum furnace. The hardness of the parts after heat treatment is HRC58.4. The metallographic structure of the heat treatment material is tempered martensite + a small amount of carbides.

[0070] Step 8: Finish machining of the upper die foreman and the lower die insert part blanks after heat treatment. Finish machine the upper die foreman and the lower die insert part blanks after final heat treatment by grinding to meet the dimensional and precision requirements of the die.

[0071] Step 9: Assembly. Fit the machined lower die insert and the upper die foreman into the machined H13 lower die base and upper die base respectively, and then close the lower die and the upper die as shown to obtain a complete assembled aluminum and magnesium alloy extrusion die.

[0072] As described above, it is only the preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and all should be covered within the protection scope of the present invention.

Claims

1. A method for manufacturing a bimetallic combination of a self-lubricating extrusion die, wherein the upper die head insert and the lower die cavity insert of the die are made of eutectic graphite steel, and the other parts of the upper die and the lower die are made of H13 steel, characterized in that, Specifically including: Step 1: According to the composition requirements of the eutectic graphite steel, calculate the percentage contents of raw materials such as pig iron, scrap steel, pure Ni plate, ferrotungsten, ferromolybdenum, ferrovanadium, ferrochrome, aluminum block, inoculant, and spheroidizing agent, and weigh each raw material according to the calculated percentage of each raw material and the weight of the molten iron for specific melting and preparation; the eutectic graphite steel is composed of the following elements: C: 3.62 - 3.7 wt%, Si: 2.3 - 2.56 wt%, Ni: 6.5 - 8.2 wt%, W: 1.0 - 3.0 wt%, Mo: 1.0 - 2.0 wt%, V: 0.5 - 1.5 wt%, Cr: 0.5 - 1.5 wt%, Al: 0.7 - 1.6 wt%, Mg: 0.03 - 0.04 wt%, and the balance is Fe; Step 2: Melt the raw materials weighed in Step 1 into molten iron in an induction furnace; Step 3: Cast the molten iron melted in Step 2 into profiles of upper die head inserts or lower die cavity inserts; Step 4: Perform stress relief annealing on the profiles of the upper die head inserts or lower die cavity inserts cast in Step 3; Step 5: Perform solution treatment and composition homogenization annealing on the stress-relieved profiles of the upper die head inserts or lower die cavity inserts; Step 6: Cut the profiles of the upper die head inserts or lower die cavity inserts by wire cutting and machine them into part blanks of the upper die head inserts or lower die cavity inserts by machining; Step 7: Perform heat treatment tempering on the machined part blanks of the upper die head inserts or lower die cavity inserts; Step 8: Finish machining the part blanks of the upper die head inserts and lower die cavity inserts after final heat treatment by grinding; Step 9: Inlay the machined lower die cavity inserts into the machined lower die, inlay the machined upper die head inserts into the machined upper die, and then close the lower die and the upper die to obtain a complete aluminum and magnesium alloy extrusion die assembled together.

2. The manufacturing method according to claim 1, characterized in that, The melting temperature of the molten iron in Step 2 is 1530 - 1550 °C.

3. The manufacturing method according to claim 1, characterized in that, The casting temperature of the molten iron in Step 3 is 1410 - 1430 °C.

4. The manufacturing method according to claim 1, characterized in that, The number of graphite balls in the profile obtained in the third step is between 300 / mm 2 ~500 / mm 2 and the graphite volume fraction is greater than 6%.

5. The manufacturing method according to claim 1, characterized in that, The stress relief annealing temperature in Step 4 is: 550 - 600 °C, and the holding time is 3h - 5h.

6. The manufacturing method according to claim 1, characterized in that, The specific solution treatment and composition homogenization annealing process in Step 5 is as follows: Solution and composition homogenization are carried out simultaneously, and the treatment process is 1000 - 1100 °C, holding for 9h - 12h; after solution, it is cooled with the furnace to 750 - 800 °C and held for 2h - 3h; then it is furnace-cooled to 620 - 670 °C and held for 6h - 8h; after completion, it is taken out of the furnace and air-cooled to room temperature.

7. The manufacturing method according to claim 6, characterized in that, The solution treatment and composition homogenization annealing process are carried out under a protective atmosphere or in a vacuum condition.

8. The manufacturing method according to claim 1, characterized in that, The outer cylindrical surface of the lower die cavity insert and its mating inner surface of the lower die are both machined with a taper of 1° - 3°.

9. The method according to claim 1, characterized in that, The specific heat treatment tempering process in Step 7 is as follows: Hold at 1000 - 1050 °C for 1h, then water-cool, and then hold at 500 - 600 °C for 1h and furnace-cool, and the process of holding at 500 - 600 °C for 1h and furnace-cool is repeated 2 - 3 times; or After holding at 880 - 950 °C for 1 h, furnace cool to 600 °C, then take out of the furnace and air cool, and then temper at 500 °C for 1 h; Among them, the heating process is carried out in an atmosphere furnace or a vacuum furnace.

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