A gas valve alloy with high hardness and high durability and a preparation method thereof

Abstract

The application discloses a gas valve alloy with high hardness and high durability and a preparation method thereof. The chemical components of the gas valve alloy are as follows: C: 0.18-0.22%, Cr: 22-24%, Ni: 12-14%, Mo: 2.5-3.5%, W: 1.5-2.5%, Ti: 0.8-1.2%, Al: 0.4-0.6%, Nb: 0.3-0.5%, V: 0.15-0.25%, B: 0.01-0.015%, Ce: 0.02-0.04%, and the rest is Fe and inevitable impurities. The preparation method comprises the steps of vacuum induction furnace smelting, electroslag remelting smelting, forging, hot rolling and heat treatment. The application realizes good balance between high hardness and high durability by reasonably designing the composition and proportion of alloy elements and utilizing the synergistic strengthening effect of multi-element alloy elements. Meanwhile, the preparation process is simple, the cost is controllable, and the application is suitable for large-scale industrial production. The application solves the problem that the hardness and durability of the domestic internal combustion engine exhaust valve cannot be balanced, and greatly improves the stability and service life of the product.

Description

Technical Field

[0001] This invention belongs to the field of iron and steel metallurgy technology, specifically relating to a valve alloy that combines high hardness and high durability, and its preparation method. Background Technology

[0002] Gas valves are key components in power equipment such as internal combustion engines and aero engines. They operate in extremely harsh environments, requiring them to withstand multiple effects such as high temperature, high pressure, high-speed impact, and gas corrosion over long periods. This places extremely high demands on gas valve materials, which must not only possess excellent high-temperature hardness to resist wear, but also good high-temperature durability to ensure that they do not undergo plastic deformation or fracture during long-term high-temperature service.

[0003] Currently, existing valve alloys mainly include austenitic heat-resistant steel and nickel-based superalloys. Austenitic heat-resistant steel has a relatively low cost, but its high-temperature hardness and creep resistance are limited, making it difficult to meet the long-term service requirements of high-performance power equipment. Nickel-based superalloys, while possessing good high-temperature performance, suffer from high cost and difficult processing, limiting their large-scale application. Furthermore, some improved valve alloys attempt to enhance performance by adjusting the alloy element ratios, but this often presents a contradiction: "increased hardness leads to decreased creep resistance," making it difficult to simultaneously achieve high hardness and high creep resistance. For example, increasing the content of elements such as carbon and chromium can improve alloy hardness, but it easily leads to uneven precipitation of carbides within the alloy, reducing grain boundary strength and thus affecting creep resistance; conversely, excessive pursuit of creep resistance necessitates reducing the content of strengthening elements, resulting in insufficient hardness and accelerated wear.

[0004] Therefore, developing a valve alloy that can simultaneously achieve high hardness and high durability, while also being cost-effective and easy to manufacture, is of great significance for improving the reliability and service life of power equipment. It is also a current research hotspot and urgent need in the field of valve alloy materials. Summary of the Invention

[0005] The purpose of this invention is to provide a valve alloy that combines high hardness and high durability with its preparation method. This invention achieves a good balance between high hardness and high durability of the valve alloy, while the preparation process is simple, cost is controllable, and it is suitable for large-scale industrial production.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a valve alloy that combines high hardness and high durability, wherein the valve alloy comprises the following chemical composition by weight percentage: C: 0.18-0.22%, Cr: 22-24%, Ni: 12-14%, Mo: 2.5-3.5%, W: 1.5-2.5%, Ti: 0.8-1.2%, Al: 0.4-0.6%, Nb: 0.3-0.5%, V: 0.15-0.25%, B: 0.01-0.015%, Ce: 0.02-0.04%, with the remainder being Fe and unavoidable impurities.

[0007] Preferably, the chemical composition of the valve alloy contains 0.3-0.8% Nb+V by mass.

[0008] By selecting specific amounts of Nb and V, Nb and V can form stable MC-type carbides with C. These carbides have high hardness and good stability, significantly improving the alloy's hardness and wear resistance. Simultaneously, Nb and V can refine the grains and enhance the grain boundary strength, thereby improving the alloy's creep resistance. By rationally controlling the content of niobium and vanadium, the precipitation of fine, dispersed carbides can be effectively promoted, significantly improving the alloy's high-temperature strength and creep resistance, while maintaining good processing plasticity and microstructural stability. This achieves a good balance between high hardness and creep resistance, meeting the long-term service requirements of internal combustion engine exhaust valves under high temperature, high pressure, and corrosive environments.

[0009] Preferably, the chemical composition of the valve alloy has a C:Mo:W mass ratio of 1:13-18:7-10.

[0010] C: As a strengthening element, it can form carbides with Mo and W, significantly improving the hardness and wear resistance of the alloy. Simultaneously, an appropriate amount of C can stabilize the austenitic structure and enhance the high-temperature performance of the alloy. However, excessive C content can lead to the precipitation and aggregation of large amounts of carbides, reducing the alloy's toughness and creep resistance. Mo and W are refractory metal elements that can dissolve in the austenitic matrix to form solid solution strengthening, significantly improving the high-temperature strength and hardness of the alloy. At the same time, Mo and W can form stable carbides with C, further enhancing the alloy's wear resistance and high-temperature creep resistance. The synergistic effect of these three elements effectively balances the alloy's hardness and creep resistance.

[0011] Preferably, the valve alloy has a hardness of 45-50 HRC at room temperature and a creep strength (100h) of 250-300 MPa at 800℃.

[0012] Another object of the present invention is to provide a method for preparing a valve alloy that combines high hardness and high durability, the preparation method comprising the following steps: 1) Raw material preparation and smelting: Accurately weigh each raw material according to the mass percentage of the target alloy's chemical composition, add the weighed raw materials to a vacuum induction melting furnace, heat to 1550-1650℃, hold for 20-40 minutes, and perform electromagnetic stirring 2-3 times during this period, with each stirring time lasting 3-5 minutes, to ensure uniform composition of the molten pool; then lower the furnace temperature to 1480-1520℃ and cast to obtain an ingot; 2) Electroslag remelting: The melting rate is controlled at 2.8-3.0 kg / min, and the feeding weight is controlled at 50-70 kg; 3) Homogenization annealing: Place the ingot obtained in step 2) into a box-type resistance furnace, heat it to 1150-1200℃, hold it for 8-12 hours, and then cool it to room temperature with the furnace to eliminate the composition segregation and internal stress inside the ingot. 4) Hot working: After holding at 1050-1100℃ for 2-4 hours, forging is carried out. The final forging temperature shall not be lower than 900℃, and slow cooling is performed. After holding at 1000-1080℃ for 3-5 hours, hot rolling is carried out. 5) Solution heat treatment: The hot-rolled bar is heated in a heating furnace and then rapidly water-cooled to room temperature to obtain a uniform austenitic structure; 6) Aging heat treatment: The solution product is heated in a heating furnace and then air-cooled to room temperature.

[0013] Preferably, in step 1) raw material preparation and smelting, the raw materials selected are industrial pure iron, industrial pure chromium, industrial pure nickel, ferromolybdenum, ferrotungsten, ferrotitanium, aluminum ingots, ferroniobium, ferrovanadium, ferroboron, and rare earth cerium blocks with a purity of not less than 99.5%.

[0014] Preferably, in step 1) raw material preparation and melting, the pouring speed during vacuum induction melting is controlled at 1-1.5 kg / s.

[0015] Preferably, step 4) hot working, forging is a three-stage drawing followed by elongation.

[0016] Preferably, step 5) solution heat treatment: the hot-rolled bar is heated to 1080-1120℃ in a heating furnace, held for 1-2 hours, and then rapidly water-cooled to room temperature to obtain a uniform austenitic structure.

[0017] Step 6) Aging heat treatment: The solid solution product is heated to 720-760℃ in a heating furnace, kept at that temperature for 4-6 hours, and then air-cooled to room temperature.

[0018] Preferably, the forging process employs a specific temperature combined with three-stage forging and three-stage drawing, which can effectively refine the grains and improve the microstructure. At the same time, appropriate heat preservation processes can be interspersed during multiple deformation processes to achieve stress relaxation, reduce the probability of material cracking, and improve the forging qualification rate.

[0019] The beneficial effects of adopting the above technical solution are as follows: 1. By rationally designing the composition and ratio of multiple alloying elements, this invention utilizes the synergistic effect of carbide strengthening formed by elements such as C, Cr, Mo, and W, γ' phase precipitation strengthening formed by Ti, Al, and Ni, and grain boundary strengthening by B, effectively solving the technical problem of "difficulty in balancing hardness and durability" in existing valve alloys, and greatly improving the stability and lifespan of the product. The prepared alloy can achieve a hardness of 45-50 HRC at room temperature and a creep strength (100h) of 250-300 MPa at 800℃, while also possessing good oxidation resistance and corrosion resistance, meeting the extreme service requirements of high-performance power equipment valves. 2. The preparation method of this invention uses vacuum induction melting to ensure uniform and pure alloy composition, eliminates ingot segregation and internal stress through homogenization annealing, refines grains through thermoplastic processing, and then controls the microstructure and properties through solution treatment and aging strengthening. The process steps are simple and highly controllable, requiring no special complex equipment, suitable for large-scale industrial production, and the raw material cost is relatively low, making it highly economical and practical. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Example 1

[0021] This embodiment provides a valve alloy that balances high hardness and high durability. Its chemical composition, by mass percentage, is: C: 0.19%, Cr: 22.5%, Ni: 13%, Mo: 2.85%, W: 1.52%, Ti: 1.0%, Al: 0.5%, Nb: 0.4%, V: 0.2%, B: 0.012%, Ce: 0.02%, with the remainder being Fe and unavoidable impurities. The ratio of Nb+V is 0.6%, and the ratio of C:Mo:W is 1:15:8.

[0022] A method for preparing a valve alloy that combines high hardness and high durability includes the following steps: 1) Raw material preparation and smelting: Accurately weigh each raw material according to the mass percentage of the above alloy chemical composition. The raw materials selected are industrial pure iron, industrial pure chromium, industrial pure nickel, ferromolybdenum, ferrotungsten, ferrotitanium, aluminum ingots, ferroniobium, ferrovanadium, ferroboron, and rare earth cerium blocks with a purity of not less than 99.5%. Add the weighed raw materials to a vacuum induction melting furnace, heat to 1550℃, hold for 30 minutes, and perform electromagnetic stirring twice during this period, with each stirring time being 5 minutes, to ensure uniform composition of the molten pool. Then lower the furnace temperature to 1500℃ and cast the ingot at a pouring speed of 1.2 kg / s. 2) Electroslag remelting: Melting rate controlled at 3.0 kg / min, and feeding weight controlled at 50 kg; 3) Homogenization annealing: The ingot obtained in step (1) is placed in a box-type resistance furnace, heated to 1180℃, held for 10h, and then cooled to room temperature with the furnace to eliminate the component segregation and internal stress inside the ingot. 4) Hot working: After holding at 1090℃ for 3 hours, forging is carried out by three-stage forging and three-stage drawing, with a final forging temperature of 915℃ and slow cooling; after holding at 1050℃ for 4 hours, hot rolling is carried out. 5) Solution heat treatment: The hot-rolled bar is heated to 1100℃ in a heating furnace, held for 1.5h, and then rapidly water-cooled to room temperature to obtain a uniform austenitic structure. 6) Aging heat treatment: Heat the solution product to 720℃ in a heating furnace, hold for 6 hours, and then air cool to room temperature. Example 2

[0023] The difference between this embodiment and Embodiment 1 is that the high-hardness, high-durability valve alloy, by mass percentage, has the following chemical composition: C: 0.21%, Cr: 22.8%, Ni: 13.2%, Mo: 2.73%, W: 1.89%, Ti: 1.1%, Al: 0.53%, Nb: 0.3%, V: 0.16%, B: 0.015%, Ce: 0.023%, with the remainder being Fe and unavoidable impurities. Specifically, the Nb+V ratio is 0.46%, and the C:Mo:W ratio is 1:13:9.

[0024] A method for preparing a valve alloy that combines high hardness and high durability includes the following steps: 1) Raw material preparation and smelting: Accurately weigh each raw material according to the mass percentage of the above alloy chemical composition. The raw materials selected are industrial pure iron, industrial pure chromium, industrial pure nickel, ferromolybdenum, ferrotungsten, ferrotitanium, aluminum ingots, ferroniobium, ferrovanadium, ferroboron, and rare earth cerium blocks with a purity of not less than 99.5%. Add the weighed raw materials to a vacuum induction melting furnace, heat to 1635℃, hold for 25 minutes, and perform electromagnetic stirring twice during this period, with each stirring time being 4 minutes, to ensure uniform composition of the molten pool. Then lower the furnace temperature to 1485℃ and cast the ingot at a pouring speed of 1.5 kg / s. 2) Electroslag remelting: Melting rate controlled at 2.8 kg / min, and feeding weight controlled at 65 kg; 3) Homogenization annealing: The ingot obtained in step (1) is placed in a box-type resistance furnace, heated to 1155℃, held for 12 hours, and then cooled to room temperature with the furnace to eliminate component segregation and internal stress inside the ingot. 4) Hot working: After holding at 1055℃ for 4 hours, forging is carried out by three-stage forging and three-stage drawing, with a final forging temperature of 930℃ and slow cooling; after holding at 1080℃ for 3 hours, hot rolling is carried out. 5) Solution heat treatment: The hot-rolled bar is heated to 1085℃ in a heating furnace, held for 2 hours, and then rapidly water-cooled to room temperature to obtain a uniform austenitic structure. 6) Aging heat treatment: Heat the solution product to 760℃ in a heating furnace, hold for 4 hours, and then air cool to room temperature. Example 3

[0025] The difference between this embodiment and Embodiment 1 is that the high-hardness, high-durability valve alloy, by mass percentage, has the following chemical composition: C: 0.20%, Cr: 23.5%, Ni: 12.5%, Mo: 3.4%, W: 2.0%, Ti: 1.0%, Al: 0.55%, Nb: 0.45%, V: 0.35%, B: 0.013%, Ce: 0.020%, with the remainder being Fe and unavoidable impurities. Specifically, the Nb+V ratio is 0.8%, and the C:Mo:W ratio is 1:17:10.

[0026] A method for preparing a valve alloy that combines high hardness and high durability includes the following steps: 1) Raw material preparation and smelting: Accurately weigh each raw material according to the mass percentage of the above alloy chemical composition. The raw materials selected are industrial pure iron, industrial pure chromium, industrial pure nickel, ferromolybdenum, ferrotungsten, ferrotitanium, aluminum ingots, ferroniobium, ferrovanadium, ferroboron, and rare earth cerium blocks with a purity of not less than 99.5%. Add the weighed raw materials to a vacuum induction melting furnace, heat to 1600℃, hold for 40 minutes, and perform electromagnetic stirring 3 times during this period, with each stirring time being 3 minutes, to ensure uniform composition of the molten pool. Then lower the furnace temperature to 1520℃ and cast the ingot at a pouring speed of 1.0 kg / s. 2) Electroslag remelting: Melting rate controlled at 2.9 kg / min, and feeding weight controlled at 70 kg; 3) Homogenization annealing: The ingot obtained in step (1) is placed in a box-type resistance furnace, heated to 1195℃, held for 9 hours, and then cooled to room temperature with the furnace to eliminate the component segregation and internal stress inside the ingot. 4) Hot working: After holding at 1065℃ for 2 hours, forging is carried out by three-stage forging and three-stage drawing, with a final forging temperature of 925℃ and slow cooling; after holding at 1020℃ for 5 hours, hot rolling is carried out. 5) Solution heat treatment: The hot-rolled bar is heated to 1120℃ in a heating furnace, held for 1 hour, and then rapidly water-cooled to room temperature to obtain a uniform austenitic structure. 6) Aging heat treatment: Heat the solution product to 745℃ in a heating furnace, hold for 5 hours, and then air cool to room temperature.

[0027] Comparative Example 1 The difference between this embodiment and Embodiment 1 is that the valve alloy, by mass percentage, has the following chemical composition: C: 0.20%, Cr: 22.7%, Ni: 13.0%, Mo: 3.0%, W: 1.6%, Ti: 1.05%, Al: 0.55%, Nb: 0.2%, V: 0.05%, B: 0.012%, Ce: 0.02%, with the remainder being Fe and unavoidable impurities.

[0028] The composition is: Nb+V=0.25, C:Mo:W=1:15:8.

[0029] Comparative Example 2 The difference between this embodiment and Embodiment 1 is that the valve alloy, by mass percentage, has the following chemical composition: C: 0.20%, Cr: 22.5%, Ni: 13.0%, Mo: 2.0%, W: 1.2%, Ti: 1.0%, Al: 0.55%, Nb: 0.4%, V: 0.2%, B: 0.012%, Ce: 0.02%, with the remainder being Fe and unavoidable impurities.

[0030] The composition is: Nb+V=0.6, C:Mo:W=1:10:6.

[0031] Comparative Example 3 The difference between this embodiment and Embodiment 1 is that the preparation method of the valve alloy includes the following steps: (1) Raw material preparation and smelting: Weigh each raw material accurately according to the mass percentage of the above alloy chemical composition. The raw materials selected are industrial pure iron, industrial pure chromium, industrial pure nickel, ferromolybdenum, ferrotungsten, ferrotitanium, aluminum ingots, ferroniobium, ferrovanadium, ferroboron, and rare earth cerium blocks with a purity of not less than 99.5%. Add the weighed raw materials to the vacuum induction melting furnace, heat to 1550℃, and hold for 30 minutes. During this period, perform electromagnetic stirring twice, each stirring time is 5 minutes, to ensure that the composition of the molten pool is uniform. Then lower the furnace temperature to 1500℃ and cast the ingot at a casting speed of 2 kg / s. (2) Electroslag remelting; (3) Homogenization annealing: The ingot obtained in step (1) is placed in a box-type resistance furnace, heated to 1180℃, held for 10h, and then cooled to room temperature with the furnace to eliminate the component segregation and internal stress inside the ingot. (4) Hot working: After holding at 1090℃ for 3 hours, forging is carried out by three-stage forging and three-stage drawing, with a final forging temperature of 915℃ and slow cooling; after holding at 1050℃ for 4 hours, hot rolling is carried out.

[0032] (5) Solution heat treatment: The hot-rolled bar is heated to 1100℃ in a heating furnace, held for 1.5h, and then rapidly water-cooled to room temperature to obtain a uniform austenitic structure. (6) Aging heat treatment: The solid solution product is heated to 720°C in a heating furnace, kept at that temperature for 6 hours, and then air-cooled to room temperature.

[0033] Comparative Example 4 The difference between this embodiment and Embodiment 1 is that the preparation method of the valve alloy includes the following steps: (1) Raw material preparation and smelting: Weigh each raw material accurately according to the mass percentage of the above alloy chemical composition. The raw materials selected are industrial pure iron, industrial pure chromium, industrial pure nickel, ferromolybdenum, ferrotungsten, ferrotitanium, aluminum ingots, ferroniobium, ferrovanadium, ferroboron, and rare earth cerium blocks with a purity of not less than 99.5%. Add the weighed raw materials to the vacuum induction melting furnace, heat to 1550℃, and hold for 30 minutes. During this period, perform electromagnetic stirring twice, each stirring time is 5 minutes, to ensure that the composition of the molten pool is uniform. Then lower the furnace temperature to 1500℃ and cast the ingot at a casting speed of 1.2 kg / s. (2) Electroslag remelting; (3) Homogenization annealing: The ingot obtained in step (1) is placed in a box-type resistance furnace, heated to 1180℃, held for 10h, and then cooled to room temperature with the furnace to eliminate the component segregation and internal stress inside the ingot. (4) Hot working: After holding at 1090℃ for 3 hours, forging is carried out by single-direction drawing, and the final forging temperature is 915℃, followed by slow cooling; after holding at 1050℃ for 4 hours, hot rolling is carried out.

[0034] (5) Solution heat treatment: The hot-rolled bar is heated to 1100℃ in a heating furnace, held for 1.5h, and then rapidly water-cooled to room temperature to obtain a uniform austenitic structure. (6) Aging heat treatment: The solid solution product is heated to 720°C in a heating furnace, kept at that temperature for 6 hours, and then air-cooled to room temperature.

[0035] The mechanical property test results of the valve alloy products obtained in the above embodiments and comparative examples are shown in Table 1. Performance testing Table 1 Mechanical properties of nickel-based alloys in each embodiment

[0036] As shown in Table 1, the valve alloys prepared in Examples 1-3 of this invention have a room temperature hardness of 45-50 HRC and a high-temperature creep strength (100h) of 250-300 MPa, which are significantly higher than those of the conventional valve alloys in Comparative Examples 1+4. This indicates that the valve alloys of this invention can simultaneously achieve high hardness and high creep performance, fully meeting the service requirements of high-performance power equipment valves.

[0037] The above embodiments are only used to illustrate and not limit the technical solutions of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the present invention without departing from the spirit and scope of the present invention. Any modifications or partial substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A valve alloy that combines high hardness and high durability, characterized in that, The valve alloy comprises the following chemical composition by weight percentage: C: 0.18-0.22%, Cr: 22-24%, Ni: 12-14%, Mo: 2.5-3.5%, W: 1.5-2.5%, Ti: 0.8-1.2%, Al: 0.4-0.6%, Nb: 0.3-0.5%, V: 0.15-0.25%, B: 0.01-0.015%, Ce: 0.02-0.04%, with the remainder being Fe and unavoidable impurities.

2. The valve alloy according to claim 1, which combines high hardness and high durability, is characterized in that... The chemical composition of the valve alloy contains 0.3-0.8% Nb and V by mass.

3. The valve alloy according to claim 1, which combines high hardness and high durability, is characterized in that... The chemical composition of the valve alloy has a C:Mo:W mass ratio of 1:13-18:7-10.

4. The valve alloy according to claim 1, which combines high hardness and high durability, is characterized in that... The valve alloy has a hardness of 45-50 HRC at room temperature and a creep strength of 250-300 MPa at 800℃ for 100 hours.

5. A method for preparing a valve alloy that combines high hardness and high durability according to any one of claims 1-4, characterized in that, The preparation method includes the following steps: 1) Raw material preparation and smelting: Accurately weigh each raw material according to the mass percentage of the target alloy's chemical composition, add the weighed raw materials to a vacuum induction melting furnace, heat to 1550-1650℃, hold for 20-40 minutes, and perform electromagnetic stirring 2-3 times during this period, with each stirring time lasting 3-5 minutes; then lower the furnace temperature to 1480-1520℃ and cast to obtain an ingot; 2) Electroslag remelting: The melting rate is controlled at 2.8-3.0 kg / min, and the feeding weight is controlled at 50-70 kg; 3) Homogenization annealing: Place the ingot obtained in step 2) into a box-type resistance furnace, heat it to 1150-1200℃, hold it for 8-12 hours, and then cool it to room temperature with the furnace. 4) Hot working: After holding at 1050-1100℃ for 2-4 hours, forging is carried out. The final forging temperature shall not be lower than 900℃, and slow cooling is performed. After holding at 1000-1080℃ for 3-5 hours, hot rolling is carried out. 5) Solution heat treatment: The hot-rolled bar is heated in a heating furnace and then rapidly water-cooled to room temperature; 6) Aging heat treatment: The solution product is heated in a heating furnace and then air-cooled to room temperature.

6. A method for preparing a valve alloy that combines high hardness and high durability according to claim 5, characterized in that, Step 1) Raw material preparation and smelting: The raw materials selected are industrial pure iron, industrial pure chromium, industrial pure nickel, ferromolybdenum, ferrotungsten, ferrotitanium, aluminum ingots, ferroniobium, ferrovanadium, ferroboron, and rare earth cerium blocks with a purity of not less than 99.5%.

7. A method for preparing a valve alloy that combines high hardness and high durability according to claim 5, characterized in that, In step 1), raw material preparation and smelting, the pouring speed during vacuum induction smelting is controlled at 1-1.5 kg / s.

8. A method for preparing a valve alloy that combines high hardness and high durability according to any one of claims 5-7, characterized in that, Step 4) Hot working, forging process is three-stage drawing and then elongation.

9. A method for preparing a valve alloy that combines high hardness and high durability according to any one of claims 5-7, characterized in that, Step 5) Solution heat treatment: The hot-rolled bar is heated to 1080-1120℃ in a heating furnace, held for 1-2 hours, and then rapidly water-cooled to room temperature.

10. A method for preparing a valve alloy that combines high hardness and high durability according to any one of claims 5-7, characterized in that, Step 6) Aging heat treatment: The solution product is heated to 720-760℃ in a heating furnace, held for 4-6 hours, and then air-cooled to room temperature.

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