A UNS N0 7252 alloy and its manufacturing method and application

Abstract

The present invention provides a UNS NO 7252 alloy and its manufacturing method and application, comprising the following steps: S1: preparing a graphite carbon block, a metal cobalt sheet, a pure iron block, a metal chromium, an electrolytic nickel, a molybdenum bar, a metal manganese, and a metal silicon, pre-baking and sequentially loading them into a crucible of a vacuum induction melting furnace for smelting to obtain a vacuum induction ingot; S2: preparing an electroslag remelting electrode, grinding the induction ingot until the surface is fully metallic, preheating and welding an auxiliary electrode, performing electroslag remelting, obtaining a steel ingot after electroslag remelting, and air cooling; S3: placing the steel ingot obtained in step S2 on a furnace bottom plate, performing a homogenization treatment, and forging at a forging temperature of 980-1170°C; S4: rolling and solution treatment; S5: aging treatment to obtain the UNS NO 7252 alloy. The present invention provides a preparation method of the UNS NO 7252 alloy and a UNS NO 7252 nut. The invention solves the problems of poor hot working performance and low yield of conventional UNS N0 7252 alloy.

Description

Technical Field

[0001] The present invention relates to the field of high-temperature alloys, and in particular to a UNS N0 7252 alloy and a manufacturing method and application thereof. Background Art

[0002] High-temperature alloys refer to a type of metal material based on iron, nickel and cobalt, which can work for a long time at high temperatures above 600°C and under certain stresses. They have excellent high-temperature strength, good oxidation resistance and thermal corrosion resistance, good fatigue performance, fracture toughness and other comprehensive properties. They are also called "superalloys." They are mainly used in the aerospace and energy fields. High-temperature alloys can be roughly divided into iron-based high-temperature alloys, nickel-based high-temperature alloys and cobalt-based high-temperature alloys according to their composition, and can be divided into solid solution strengthening type, precipitation hardening type and dispersion strengthening type according to the strengthening method.

[0003] UNS N07252 is a nickel-chromium-cobalt-based precipitation-hardening superalloy. Its primary strengthening phases are age-precipitated γ' phase and M6C carbides. Aging heat treatment significantly increases the alloy's strength while also providing excellent machinability. It is suitable for components requiring oxidation resistance at temperatures below 980°C. UNS N07252 is widely used in aircraft engine applications such as combustion chamber liners, high-pressure turbine outer rings, high-pressure guide vanes, combustion chamber aft casings, seals, fasteners, and high-temperature springs.

[0004] Due to the high content of aluminum, titanium and molybdenum elements in this alloy, there is a problem of difficulty in opening the ingot during the production and forging process. The production cost is high and the requirements for the equipment used are also relatively high. Summary of the Invention

[0005] One of the technical problems to be solved by the present invention is to provide a method for manufacturing UNS N0 7252 alloy nuts to solve the problems of difficulty in ingot blanking and high production cost in conventional production forging processes.

[0006] To solve the above problems, the present invention provides a method for manufacturing UNS N0 7252 alloy nuts, which is characterized by comprising the following steps:

[0007] S1: Graphite carbon blocks, metal cobalt sheets, pure iron blocks, metal chromium, electrolytic nickel, molybdenum bars, metal manganese, and metal silicon are mixed, pre-baked, and sequentially loaded into a crucible of a vacuum induction melting furnace for melting to obtain a vacuum induction ingot;

[0008] S2: The vacuum induction ingot obtained in step S1 is made into an electroslag remelting electrode, the induction electrode is ground until the surface is full metallic color, and after preheating, an auxiliary electrode is welded and electroslag remelting is performed to obtain a steel ingot, which is then air-cooled;

[0009] S3: placing the steel ingot obtained in step S2 on the furnace bottom plate, performing homogenization treatment and forging, wherein the forging temperature is 980-1170° C.;

[0010] S4: rolling and solution treating the billet after the treatment in step S3;

[0011] S5: Performing aging treatment on the product after the treatment in step S4 to obtain UNS N0 7252 alloy.

[0012] As a preferred solution, in step S1, the graphite carbon block, metal cobalt sheet, pure iron block, metal chromium, electrolytic nickel, molybdenum bar, metal manganese, and metal silicon are placed in order from bottom to top in the crucible of the vacuum induction melting furnace.

[0013] As a preferred solution, in step S1, the smelting condition is: heating at a temperature of 200°C for 4 hours; in step S2, the preheating condition is: heating at a temperature of 200°C for 4 hours.

[0014] As a preferred solution, in step S2, the slag system used in the electroslag remelting is a CaF2:Al2O3:CaO:MgO:TiO2 slag system with a ratio of 49:21:20:5:3, and the slag system is preheated at 800°C for 4 hours before use.

[0015] As a preferred solution, in step S2, the electroslag remelting includes:

[0016] A: Slag stage: secondary side current: 2000-4000A, secondary side voltage: 48-50V, time ≥25min;

[0017] B: Arc starting stage: secondary side current: 4000-6000A, secondary side voltage: 50-52V, time ≥40min;

[0018] C: Steady-state stage: secondary side current: 6000-7500A, secondary side voltage: 52-56V, time ≥ ingot weight / 4min;

[0019] D: Feeding stage: secondary side current: 7500-3000A, secondary side voltage: 48-56V, time ≥40min.

[0020] As a preferred solution, in step S3, the homogenization process includes:

[0021] The first heat preservation: keep warm at 600℃ for 4 hours; the first temperature rise: heat up with the furnace to 900℃, the heating time is 3 hours; the second heat preservation: keep warm at 900℃ for 3 hours; the second temperature rise: heat up with the furnace to 1200℃, the heating time is 2 hours; the third heat preservation: keep warm at 1200℃ for 22h; the first temperature drop: cool down with the furnace to 1150℃; the fourth heat preservation: keep warm at 1150℃ for 4 hours; the second temperature drop: air cooling with the furnace.

[0022] As a preferred solution, in step S4, the solution treatment includes: heating the rolled steel ingot to 1080±14°C in a furnace, keeping the temperature, and then rapidly immersing the ingot in water for cooling, wherein the temperature of the water is ≤40°C.

[0023] As a preferred solution, in step S5, the aging treatment includes: heating the product to 715±14° C. in a furnace, keeping the temperature for 20 hours, and then air-cooling the product.

[0024] One of the technical problems to be solved by the present invention is to provide a method for manufacturing UNS N0 7252 alloy nuts to solve the problems of low yield and average performance of conventional UNS N0 7252 alloy production.

[0025] In order to solve the above problems, the present invention provides a UNS N0 7252 alloy prepared by the above method, wherein the alloy comprises the following components by mass ratio:

[0026] C: 0.1-0.2%; Cr: 18-20%; Ti: 2.25-2.75%; Al: 0.75-1.25%; Co: 9.00-11.00%; Fe: 0-5.00%; Mn: 0-0.50%; Si: 0-0.50%; Mo: 9.00-10.50; P: 0-0.015%; S: 0-0.015%; B: 0.01-0.003%; the balance is Ni and other inevitable impurities.

[0027] Another technical problem to be solved by the present invention is to provide a method for manufacturing UNS N0 7252 alloy nuts to solve the problem that conventional UNS N0 7252 nuts have low yield and average performance.

[0028] In order to solve the above problems, the present invention provides a method for manufacturing UNS N07252 nuts, comprising the following steps:

[0029] S1: Graphite carbon blocks, cobalt metal sheets, pure iron blocks, chromium metal, electrolytic nickel, molybdenum bars, manganese metal, and silicon metal are mixed, pre-baked, and loaded into a crucible of a vacuum induction melting furnace for melting to obtain a vacuum induction ingot;

[0030] S2: The vacuum induction ingot obtained in step S1 is made into an electroslag remelting electrode, the induction electrode is ground until the surface is full metallic color, and after preheating, an auxiliary electrode is welded and electroslag remelting is performed to obtain a steel ingot, which is then air-cooled;

[0031] S3: placing the steel ingot obtained in step S2 on the furnace bottom plate, performing homogenization treatment and forging, wherein the forging temperature is 980-1170° C.;

[0032] S4: rolling the billet processed in step S3 into a round bar and performing a solution treatment;

[0033] S5: The round bar obtained by the solution treatment is peeled and subjected to aging treatment. The round bar obtained after the aging treatment is polished and then processed to obtain UNS N07252 nuts.

[0034] In the preparation method of the UNS N0 7252 alloy and UNS N0 7252 nut described above, the oxygen, nitrogen, and hydrogen gas contents of the alloy material are reduced by optimizing the vacuum induction melting process. At the same time, the alloy ingot is subjected to a reasonable homogenization treatment to improve the hot working plasticity of the UNS N0 7252 alloy, thereby improving the hot working performance of the alloy. In addition, the metal principle ratio of the UNS N0 7252 alloy and the UNS N0 7252 nut is reasonably regulated, thereby reducing the cracking problem of the UNS N0 7252 nickel-based alloy during hot working and improving the product yield. The special hot treatment process realizes the excellent comprehensive performance of the UNS N0 7252 alloy nut. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 Heat treatment curve diagram for homogenization treatment;

[0036] Figure 2 This is the forging deformation flow chart;

[0037] Figure 3 is the solution heat treatment curve;

[0038] Figure 4 This is the heat treatment curve for aging treatment;

[0039] Figure 5 This is a schematic diagram of M24 nut processing;

[0040] Figure 6 Schematic diagram of sample sampling. DETAILED DESCRIPTION

[0041] The technical solution of the present invention will be described clearly and completely below. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0042] The present invention provides a forging method of UNS N0 7252 alloy, comprising the following steps:

[0043] S1: Graphite carbon blocks, metal cobalt sheets, pure iron blocks, metal chromium, electrolytic nickel, molybdenum bars, metal manganese, and metal silicon are mixed, pre-baked, and sequentially loaded into a crucible of a vacuum induction melting furnace for melting to obtain a vacuum induction ingot;

[0044] S2: The vacuum induction ingot obtained in step S1 is made into an electroslag remelting electrode, the induction electrode is ground until the surface is full metallic color, and after preheating, an auxiliary electrode is welded and electroslag remelting is performed to obtain a steel ingot, which is then air-cooled;

[0045] S3: placing the steel ingot obtained in step S2 on the furnace bottom plate, performing homogenization treatment and forging, wherein the forging temperature is 980-1170° C.;

[0046] S4: rolling and solution treating the billet after the treatment in step S3;

[0047] S5: Performing aging treatment on the product after the treatment in step S4 to obtain UNS N0 7252 alloy.

[0048] Preferably, in step S1, the graphite carbon block, metal cobalt sheet, pure iron block, metal chromium, electrolytic nickel, molybdenum bar, metal manganese, and metal silicon are placed in order from bottom to top in the crucible of the vacuum induction melting furnace.

[0049] Preferably, in the step S1, the smelting condition is: heating at a temperature of 200°C for 4 hours; in the step S2, the preheating condition is: heating at a temperature of 200°C for 4 hours.

[0050] Preferably, in step S2, the slag system used in the electroslag remelting is a CaF2:Al2O3:CaO:MgO:TiO2 slag system with a ratio of 49:21:20:5:3, and the slag system is preheated at 800°C for 4 hours before use.

[0051] Preferably, in step S2, the electroslag remelting includes:

[0052] A: Slag stage: secondary side current: 2000-4000A, secondary side voltage: 48-50V, time ≥25min;

[0053] B: Arc starting stage: secondary side current: 4000-6000A, secondary side voltage: 50-52V, time ≥40min;

[0054] C: Steady-state stage: secondary side current: 6000-7500A, secondary side voltage: 52-56V, time ≥ ingot weight / 4min;

[0055] D: Feeding stage: secondary side current: 7500-3000A, secondary side voltage: 48-56V, time ≥40min.

[0056] Preferably, in step S3, the homogenization process includes:

[0057] The first heat preservation: keep warm at 600℃ for 4 hours; the first temperature rise: heat up with the furnace to 900℃, the heating time is 3 hours; the second heat preservation: keep warm at 900℃ for 3 hours; the second temperature rise: heat up with the furnace to 1200℃, the heating time is 2 hours; the third heat preservation: keep warm at 1200℃ for 22h; the first temperature drop: cool down with the furnace to 1150℃; the fourth heat preservation: keep warm at 1150℃ for 4 hours; the second temperature drop: air cooling with the furnace.

[0058] Preferably, in step S4, the solution treatment comprises: heating the rolled steel ingot to 1080±14°C, keeping the temperature, and then rapidly immersing the ingot in water for cooling, wherein the temperature of the water is ≤40°C.

[0059] Preferably, in step S5, the aging treatment includes: heating the product to 715±14° C. in a furnace, keeping the temperature for 20 hours, and then air-cooling the product.

[0060] The present invention provides a UNS N0 7252 alloy prepared by the above method, wherein the alloy comprises the following components by mass ratio:

[0061] C: 0.1-0.2%; Cr: 18-20%; Ti: 2.25-2.75%; Al: 0.75-1.25%; Co: 9.00-11.00%; Fe: 0-5.00%; Mn: 0-0.50%; Si: 0-0.50%; Mo: 9.00-10.50; P: 0-0.015%; S: 0-0.015%; B: 0.01-0.003%; the balance is Ni and other inevitable impurities.

[0062] The present invention also provides a method for manufacturing a UNS N07252 nut, comprising the following steps:

[0063] S1: Graphite carbon blocks, metal cobalt sheets, pure iron blocks, metal chromium, electrolytic nickel, molybdenum bars, metal manganese, and metal silicon are mixed, pre-baked, and loaded into a crucible of a vacuum induction melting furnace for melting to obtain a vacuum induction ingot;

[0064] S2: The vacuum induction ingot obtained in step S1 is made into an electroslag remelting electrode, the induction electrode is ground until the surface is full metallic color, and after preheating, an auxiliary electrode is welded and electroslag remelting is performed to obtain a steel ingot, which is then air-cooled;

[0065] S3: placing the steel ingot obtained in step S2 on the furnace bottom plate, performing homogenization treatment and forging, wherein the forging temperature is 980-1170° C.;

[0066] S4: rolling the billet processed in step S3 into a round bar and performing a solution treatment;

[0067] S5: The round bar obtained by the solution treatment is peeled and subjected to aging treatment. The round bar obtained after the aging treatment is polished and then processed to obtain UNS N07252 nuts.

[0068] The present invention is further illustrated by way of examples, but the invention is not limited to the examples. Test methods in the following examples, where specific conditions are not specified, were performed using conventional methods and conditions selected according to the product specifications. The testing equipment used in the examples included a SPECTROMAX direct-reading spectrometer, a LECO nitrogen, hydrogen, and oxygen analyzer, an Yingzhicheng carbon and sulfur analyzer, a SANS pendulum impact tester with a cryogenic chamber, a SANS electronic universal tensile tester with an environmental chamber, a Leica optical microscope with a ZEISS lens, and a Caikang optical Rockwell hardness tester.

[0069] The following is a description of the method for preparing UNS N0 7252 nickel-based alloy nuts according to the present invention:

[0070] The present invention provides a process for manufacturing UNS N0 7252 nickel-based alloy nuts, and the process scheme is as follows:

[0071] S1: Selected raw materials such as graphite carbon blocks, metal cobalt flakes, metal silicon, metal chromium, electrolytic nickel, and metal manganese are mixed according to the standard composition range of UNS No. 7252 in ASTM B637. After baking at 200°C for 4 hours, they are loaded into a crucible in a 2-ton vacuum induction melting furnace as shown below;

[0072] Carbon blocks and pure iron blocks with high oxygen content are placed at the bottom of the furnace. At the initial stage of melting, a molten pool with high oxygen and carbon content is formed. At the same time, a high vacuum degree below 1Pa is combined, which is very conducive to the occurrence of the C+O=CO reaction. The oxygen in the molten metal is discharged through the reaction to generate CO gas. No oxides remain in the molten metal, and the purity of the material is brought to the optimal level.

[0073] The ingredients are controlled according to the internal control ingredient table in Table 1. The ingredients of the induction ingot and the measured ingredients are shown in Table 4.

[0074]

[0075] S2: After the vacuum induction casting ingot cools, the tail of the Φ260mm induction electrode is cut off by 25mm to serve as a starting plate for the same steel grade. The electrode surface is ground to a full metallic color, and compressed air is used to blow away any residual slag and moisture from the shrinkage cavity. The electrode is then preheated at 200°C for 4 hours. An auxiliary electrode is welded to the shrinkage cavity end. The weld quality is inspected and qualified before use. A Φ360 ingot is electroslag remelted using a graphite electrode for arc starting. Once a liquid slag pool forms, remelting is performed using a metal electrode. A slag system of 45 kg of CaF2:Al2O3:CaO:MgO:TiO2 in the ratio of 49:21:20:5:3 is used. The pre-melted slag is heated at 800°C for 4 hours before use. After electroslag remelting, the ingot is air-cooled.

[0076]

[0077] The composition remains basically unchanged after electroslag remelting. The changes in trace elements are attributed to analytical errors. The composition is shown in Table 6:

[0078]

[0079] S3: Homogenization and forging

[0080] a: Placement: The steel ingots should be placed on a pad with a thickness greater than 100mm and keep a gap with the furnace bottom plate. Each steel ingot should be placed at a distance of 50mm to ensure uniform heating of the steel ingots.

[0081] b: Heating: The alloy has poorer thermal conductivity than stainless steel and a greater thermal expansion coefficient than stainless steel. If the temperature is not properly raised, the thermal stress will be too large and cracks will easily occur. Therefore, controlling the heating rate and monitoring the uniformity of the furnace temperature are key. Through high-temperature and long-term homogenization treatment, the local segregation of the high-melting-point element molybdenum in the alloy ingot is eliminated, thereby avoiding cracks caused by poor local plasticity during forging heating. At the same time, the local segregation of low-melting-point elements aluminum and titanium is eliminated, and the alloy avoids the formation of micro defects and crack sources caused by the accumulation of low-melting-point elements during forging heating. After the homogenization treatment, the matrix structure of the ingot tends to be consistent and obtains good plasticity. After the homogenization treatment, it is directly forged without cooling, avoiding the thermal stress generated inside the alloy ingot due to secondary heating after cooling, while saving energy. The process curve of the alloy ingot homogenization treatment is shown in the figure below. The steel ingot is opened by a six-ton ​​free forging, and then a 750-kilogram air hammer is used to forge it into a Φ65 round bar. The forging temperature range is 980-1170℃;

[0082] Forging deformation process Figure 2 As shown;

[0083] The Φ65 round bar is rolled into Φ42mm round bar on a horizontal two-roll hot rolling mill;

[0084] S4: The rolled round bar is subjected to solution treatment.

[0085] Heat treatment is performed using an RT-180-12 high-temperature trolley resistance furnace. To ensure rigorous process control, an external thermocouple should be used to test the workpiece temperature. The holding time for quality heat treatment refers to the time after the material reaches the temperature. After the solution treatment, the material should be quickly immersed in water. The cooling water pool temperature should be ≤40°C. The solution treatment process curve is shown in Figure 3.

[0086] S5: The round bar after solution is peeled on a centerless peeling machine to Φ40mm. After peeling, it is subjected to aging treatment. The aging treatment process curve is as follows: Figure 4 As shown;

[0087] After aging treatment, the round bar is polished to Φ39.6mm and then processed into M24 nuts. Figure 5 As shown;

[0088] After the aging treatment is completed, the sample ring is cut from the workpiece and the sampling is processed by electric spark cutting and machine tools. Figure 6 shown.

[0089] The metallographic and mechanical properties of the UNS N07252 nut prepared by the above preparation method of the present invention were tested as follows:

[0090] Sample processing and testing shall be in accordance with the relevant national standards. The specific tests to be implemented are shown in the table below:

[0091]

[0092] The results of metallographic performance testing are shown in the following table:

[0093]

[0094] The results of the mechanical properties test are shown in the following table:

[0095]

[0096] The above tests further prove that the UNS N0 7252 alloy nut prepared by the present invention has excellent hot working performance, strong high-temperature endurance performance at 816°C, and good strength performance, which improves the product yield and reduces the cracking problem of UNS N0 7252 nickel-based alloy during hot working. The overall performance of the product is excellent.

[0097] Although the present disclosure is disclosed as above, the protection scope of the present disclosure is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present disclosure, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A method for producing UNS N0 7252 alloy, characterized in that: The following steps are involved: S1: Graphite carbon blocks, metal cobalt sheets, pure iron blocks, metal chromium, electrolytic nickel, molybdenum bars, metal manganese, and metal silicon are mixed, pre-baked, and sequentially loaded into a crucible of a vacuum induction melting furnace for melting to obtain a vacuum induction ingot; S2: The vacuum induction ingot obtained in step S1 is made into an electroslag remelting electrode, and the induction electrode is ground until the surface is full metallic color. After preheating, an auxiliary electrode is welded and electroslag remelting is performed. After electroslag remelting, a steel ingot is obtained, and air-cooled. S3: The steel ingot obtained in step S2 is placed on the furnace bottom plate, homogenized and forged at a temperature of 980-1170°C. S4: The billet treated in step S3 is rolled and solution treated. S5: The product treated in step S4 is aged to obtain UNS N0 7252 alloy. In step S2, the slag system used in the electroslag remelting is a CaF2:Al2O3:CaO:MgO:TiO2 slag system with a ratio of 49:21:20:5:3, and the slag system is preheated at 800°C for 4 hours before use; The electroslag remelting process includes: A: slagging stage: secondary side current: 2000-4000A, secondary side voltage: 48-50V, time ≥ 25min; B: arc starting stage: secondary side current: 4000-6000A, secondary side voltage: 50-52V, time ≥ 40min; C: steady-state stage: secondary side current: 6000-7500A, secondary side voltage: 52-56V, time ≥ ingot weight / 4min, weight in kilograms; D: feeding stage: secondary side current: 7500-3000A, secondary side voltage: 48-56V, time ≥ 40min; In step S3, the homogenization treatment includes: first heat preservation: heat preservation at 600°C for 4 hours; first temperature rise: heat preservation to 900°C with the furnace, and the heating time is 3 hours; second heat preservation: heat preservation at 900°C for 3 hours; second temperature rise: heat preservation to 1200°C with the furnace, and the heating time is 2 hours; third heat preservation: heat preservation at 1200°C for 22 hours; first temperature reduction: heat preservation to 1150°C with the furnace; fourth temperature reduction: heat preservation at 1150°C for 4 hours; second temperature reduction: air cooling with the furnace; The UNS N0 7252 alloy comprises the following components by mass ratio: C: 0.1-0.2%; Cr: 18-20%; Ti: 2.25-2.75%; Al: 0.75-1.25%; Co: 9.00-11.00%; Fe: 0-5.00%; Mn: 0-0.50%; Si: 0-0.50%; Mo: 9.00-10.50; P: 0-0.015%; S: 0-0.015%; B: 0.01-0.003%; the balance being Ni and other inevitable impurities.

2. The method for producing the UNS NO 7252 alloy according to claim 1, wherein: In the step S1, the graphite carbon block, metal cobalt sheet, pure iron block, metal chromium, electrolytic nickel, molybdenum bar, metal manganese, and metal silicon are placed in the crucible of the vacuum induction melting furnace in order from bottom to top.

3. The method for producing the UNS NO 7252 alloy according to claim 1, wherein: In the step S1, the pre-baking condition is: heating at a temperature of 200° C. for 4 hours; in the step S2, the preheating condition is: heating at a temperature of 200° C. for 4 hours.

4. The method for producing the UNS NO 7252 alloy according to claim 1, wherein: In the step S4, the solution treatment includes: heating the rolled steel ingot to 1080±14°C, keeping the temperature, and then rapidly immersing the ingot in water for cooling, wherein the temperature of the water is ≤40°C.

5. The method for producing the UNS NO 7252 alloy according to claim 1, wherein: In step S5, the aging treatment includes: heating the product to 715±14° C. in a furnace, keeping the temperature for 20 hours, and then air cooling the product.

6. An application of an alloy obtained by the method for producing UNS NO 7252 alloy according to claim 1, characterized in that: The application includes applying the UNS N0 7252 alloy to the manufacture of UNS N07252 nuts, including the following steps: S1: Graphite carbon blocks, metal cobalt sheets, pure iron blocks, metal chromium, electrolytic nickel, molybdenum bars, metal manganese, and metal silicon are mixed, pre-baked, and loaded into a crucible of a vacuum induction melting furnace for melting to obtain a vacuum induction ingot; S2: The vacuum induction ingot obtained in step S1 is made into an electroslag remelting electrode, the induction electrode is ground until the surface is full metallic color, and after preheating, an auxiliary electrode is welded and electroslag remelting is performed to obtain a steel ingot, which is then air-cooled; S3: placing the steel ingot obtained in step S2 on the furnace bottom plate, performing homogenization treatment and forging, wherein the forging temperature is 980-1170° C.; S4: rolling the billet processed in step S3 into a round bar and performing a solution treatment; S5: The round bar obtained by the solution treatment is peeled and subjected to aging treatment. The round bar obtained after the aging treatment is polished and then processed to obtain UNS N07252 nuts.

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