Manufacturing method of 00Cr27Ni31Mo7CuN alloy key pin

Abstract

The application relates to the technical field of an elongated alloy key pin, and provides a manufacturing method of a 00Cr27Ni31Mo7CuN alloy key pin, wherein the raw material of the manufacturing method is a 00Cr27Ni31Mo7CuN centerless grinding round bar, the chemical components of the 00Cr27Ni31Mo7CuN centerless grinding round bar include C 0.012%, P 0.015%, S 0.001%, Cr 26.4%, Ni 30.9%, Mn 1.42%, Si 0.04%, Mo 6.19%, Cu 1.10%, N 0.20%, and the balance of Fe and inevitable impurities, and the round bar adopts a rolling cold-drawing process and a multi-pass die shaping process. The application overcomes the defects of the prior art, is reasonable in process, convenient to operate, and solves the technical problem of low product yield of the existing alloy key pin manufacturing.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of manufacturing of an elongated alloy key pin, in particular to a manufacturing method of a 00Cr27Ni31Mo7CuN alloy key pin. BACKGROUND

[0002] 00Cr27Ni31Mo7CuN is a nitrogen-containing iron-nickel-chromium-molybdenum alloy, which has excellent overall corrosion resistance and excellent local corrosion resistance such as intergranular corrosion resistance, point corrosion resistance, crevice corrosion resistance and stress corrosion resistance, is one of the best comprehensive performance materials, and is widely used in chemical engineering such as phosphoric acid and sulfuric acid, seawater desalination, pulp, papermaking and flue gas desulfurization engineering of coal (oil) power plants.

[0003] A 00Cr27Ni31Mo7CuN alloy key pin produced by the application has a rectangular cross section with a main body of 16.3mm*15.6mm, two 1.5mm*45° chamfers on one side and two 3mm*45° chamfers on the other side, and a length of 223mm. The alloy key pin is used for connecting the stirring main shaft and the impeller of the reaction kettle in the flue gas desulfurization engineering of coal-fired power plants.

[0004] The traditional processing technology of the alloy key pin includes milling and cold drawing, and there are different technical difficulties: the former is prone to bending or twisting due to the small product size and thin diameter during the processing process, the yield is only 64.8%, and the milling of eight surfaces needs multiple clamping and tool replacement, so the production efficiency is low; the latter is prone to cracking during cold processing due to the high cold processing strength and poor plasticity of the raw material with a Cr content of 26%-28%, and the yield of the finished product is less than 30%.

[0005] Therefore, the application provides a manufacturing method of a 00Cr27Ni31Mo7CuN alloy key pin. SUMMARY

[0006] (I) Technical problems solved

[0007] In view of the shortcomings of the prior art, the application provides a manufacturing method of a 00Cr27Ni31Mo7CuN alloy key pin, which overcomes the shortcomings of the prior art, is reasonable in process, easy to operate, and solves the technical problem of low yield of the existing alloy key pin.

[0008] (II) Technical scheme

[0009] To achieve the above purpose, the application is implemented by the following technical scheme:

[0010] A manufacturing method of a 00Cr27Ni31Mo7CuN alloy key pin, characterized in that,

[0011] The raw material of the manufacturing method is a 00Cr27Ni31Mo7CuN centerless grinding round bar, and the chemical composition of the 00Cr27Ni31Mo7CuN centerless grinding round bar includes, by mass percentage, C 0.012%, P 0.015%, S 0.001%, Cr 26.4%, Ni 30.9%, Mn 1.42%, Si 0.04%, Mo 6.19%, Cu 1.10%, N 0.20%, and the balance of Fe and inevitable impurities;

[0012] The manufacturing method includes the following steps:

[0013] S11, cold drawing, after the centerless grinding round bar passes through the rectangular die hole of the rolling die, a square bar is obtained, the rolling die adopts two pairs of rotating rollers, one pair of rollers is distributed in an up-down manner, and the other pair of rollers is distributed in a left-right manner, and the rectangular die hole is formed between the rolling surfaces of the two pairs of rollers;

[0014] S12, cold drawing and shaping, the square bar passes through the first shaping die and the second shaping die in sequence to obtain a finished product with a shaped cross section;

[0015] S13, fine polishing;

[0016] S14, fine calibration;

[0017] S15, sizing;

[0018] wherein,

[0019] In step S10, the cross-sectional ratio of the bar before and after deformation through the rolling die is 12%-15%;

[0020] In step S11, the cross-sectional ratio of the bar before and after deformation through the first shaping die and the second shaping die is 8%-12% and 12%-15%, respectively.

[0021] Further, in S11 and S12, the bar is softened and solidified before cold drawing at 1160℃±10℃ for 1h, and is solidified after cold drawing at 1160℃±10℃ for 1h.

[0022] Further, the manufacturing method of the centerless grinding round bar is as follows:

[0023] S1, batching,

[0024] S2, VIM vacuum degassing control, the raw material after S1 batching is added to the VIM vacuum degassing furnace, melted, smelted by single slag method, the slag material is selected by mass ratio of 50% CaO, 26% Al2O3, 19% MgO, 5% SiO2, and the slag material accounts for 3%-5% of the mass of molten steel; the argon-oxygen ratio is controlled to 4:1 in the first-stage decarburization, the average decarburization speed is 0.0125% / min, and the carbon content is reduced to 0.2±0.05%, and the second-stage decarburization starts; the argon-oxygen ratio is controlled to 2:1 in the second-stage decarburization, the average decarburization speed is 0.0188% / min, and the carbon content is reduced to 0.12%;

[0025] S3, ESR electroslag remelting, the pre-melted slag is selected by mass ratio of 50% CaF2, 26% Al2O3, 19% CaO, 5% MgO, the pre-melted slag accounts for 3%-5% of the mass of molten steel, argon is pre-charged, the oxygen content in the crystallizer is less than 3% after the arc is started, the electroslag remelting current is 11000A-9000A, the voltage is 38-42V, and the melting speed is controlled to 6.3-6.5kg / min;

[0026] S4, homogenization treatment, 200℃±30℃, holding for 1h; heating to 950℃±15℃, heating duration≥8h; 950℃±15℃, holding for 1h; heating to 1160℃±10℃, heating duration≥3h; 1160℃±10℃, maintaining for 30h; heating to 1190℃±10℃, heating duration≥3h; 1190℃±10℃, maintaining for 60h; furnace cooling to 700℃, and then furnace-out air cooling;

[0027] S5, hot forging breakdown,

[0028] S6, rolling peeling;

[0029] S7, centerless grinding.

[0030] Further, in step S2, after the molten steel is refined in the VIM vacuum degassing furnace, argon is blown and slag is removed by using a double-bottom blowing system.

[0031] Further, in step S3, before electroslag remelting, the surface of the induction furnace vacuum electrode is polished to clean the electrode surface defects, and the electrode is baked at 600℃ for 4h, and then a false electrode is welded.

[0032] Further, in step S3, the pre-melted slag is baked at 700℃ for 4h before the electroslag starts.

[0033] (Three) beneficial effects

[0034] The application provides a manufacturing method of 00Cr27Ni31Mo7CuN alloy key pin, and has the following beneficial effects: through the purity control of raw material smelting, the property is improved by controlling the content of each element, combined with the self-developed rolling cold drawing process and multi-pass die forming process, the batch production efficiency is improved, and the product yield is improved to more than 90%. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 It is a metallographic structure photo of a forged round without homogenization treatment.

[0036] Figure 2 It is a metallographic structure photo of the 00Cr27Ni31Mo7CuN alloy key pin of the application;

[0037] Figure 3 It is a non-metallic inclusion appearance photo of the 00Cr27Ni31Mo7CuN alloy key pin of the application;

[0038] Figure 4 It is a structural schematic diagram of the rolling die of the application;

[0039] Figure 5 It is a structural schematic diagram of the forming die of the application. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical scheme and advantages of the embodiments of the application clearer, the technical scheme of the embodiments of the application will be described clearly and completely below in combination with the drawings in the embodiments of the application. Obviously, the described embodiments are part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0041] A manufacturing method of 00Cr27Ni31Mo7CuN alloy key pin, comprising the manufacturing of centerless ground round bar and the processing of the centerless ground round bar to obtain the alloy key pin.

[0042] The actual chemical composition of the 00Cr27Ni31Mo7CuN centerless ground round bar is compared with the standard requirement in Table 1 (the balance is Fe, not shown).

[0043] Table 1 Actual chemical composition and standard requirement comparison (wt%)

[0044] Element C P S Cr Ni Standard requirement ≤0.015 ≤0.02 ≤0.01 26.0-28.0 30.0-32.0 Actual composition 0.012 0.015 0.001 26.4 30.9 Element Mn Si Mo Cu N Standard requirement ≤2.00 ≤0.30 6.00-7.00 1.00-1.40 0.15-0.25 Actual composition 1.42 0.04 6.19 1.10 0.20

[0045] Chemical composition determines the basic performance of the material. In order to ensure the corrosion resistance and hot working performance of 00Cr27Ni31Mo7CuN, our company optimizes the design of the chemical composition on the basis of the standard and accurately controls it during the smelting process. P and S are harmful elements for most steels, so strict control is required for raw materials, and VIM+ESR process is used to ensure low P and low S in finished products. Cr is an indispensable alloying element in super austenitic stainless steel. The higher the chromium content, the better the corrosion resistance. This is because the alloy can form a stable surface protective film of Cr2O3 in the oxidizing medium, but too high Cr content will promote the generation of sigma phase, so the Cr content is controlled at the lower limit. Ni is the base element of super austenitic stainless steel, mainly to stabilize austenite, and nickel can also expand the passivation range and improve corrosion resistance. After considering the cost, the Ni content is controlled at the middle line. Mo can enhance the stability of the alloy surface passivation film and improve its strength and corrosion resistance, resistant to H2SO4, HCl, H3PO4 and some organic acids, resistant to pitting and crevice corrosion. But excessive Mo will also promote the generation of sigma phase, and increase the deformation resistance of the material, so the Mo content is controlled at the lower limit. N element dissolved in the matrix can improve the performance of austenitic stainless steel in resisting general corrosion medium, pitting, stress corrosion and grain boundary corrosion. But too high N content will increase the deformation resistance of the material and increase the difficulty of hot working, so the N content is controlled at the middle limit. In the corrosion medium, Cu can promote the diffusion of Cr in stainless steel to the surface of the material, accelerate the self-repairing ability of the passivation film, and thus improve the corrosion resistance of stainless steel. But considering the influence of high Cu content on hot plasticity, the Cu content is controlled at the lower limit.

[0046] The manufacturing method of 00Cr27Ni31Mo7CuN centerless grinding round bar is as follows:

[0047] S1, batching

[0048] Ni GB / T 6516-2010 Electrolytic Nickel Ni9996

[0049] Cr GB / T 3211-2008 Metal Chromium JCr99-A

[0050] Fe GB / T 9971-2017 Raw Material Pure Iron YT2

[0051] Mo GB / T 3462-2017 Molybdenum Bar and Molybdenum Plate Mo-1

[0052] Cu GB / T 467-2010 Copper Standard Copper No. 1

[0053] S2, VIM vacuum degassing control

[0054] The S1 dosed raw materials are added to a VIM vacuum degassing furnace, melted, and smelted by a single slag method to avoid the carbon increase caused by the slag making in the later stage of the double slag method. The slag material is selected by mass ratio of 50% CaO, 26% Al203, 19% MgO, and 5% Si02. The slag material accounts for 5% of the molten steel mass to improve the decarburization, desulfurization, and deoxidation efficiency. The argon-oxygen ratio is controlled to be 4:1 in the first stage decarburization. The average decarburization speed is 0.0125% / min. The carbon content is reduced to 0.2±0.05% to start the second stage decarburization. The argon-oxygen ratio is controlled to be 2:1 in the second stage decarburization. The average decarburization speed is 0.0188% / min. The carbon content is reduced to 0.12% (wt%). Different argon-oxygen ratios are blown in different decarburization stages to improve the decarburization efficiency.

[0055] After the molten steel is refined in the VIM, bottom argon blowing is continuously performed. Fine argon bubbles are blown into the ladle bottom by using a slit type gas permeable brick. The bubbles will take away the non-metallic inclusions floating in the molten steel in the floating process. The top is heated by the electrode against the top slag. The adsorption of the high basicity slag on the inclusions is fully utilized to purify the molten steel and improve the purity of the molten steel.

[0056] In the production of 00Cr27Ni31Mo7CuN, in order to better control the inclusions, the double bottom blowing system is adopted to make the inclusions in the molten steel fully float up for a long time with weak stirring. The stirring dead zone can be effectively reduced and the slag entrapment can be prevented.

[0057] S3, ESR electroslag remelting

[0058] a. Before the electroslag remelting, the surface of the induction furnace vacuum electrode is polished to clean the electrode surface defects; b. The electrode is baked at 600℃ for 4h. After baking, the false electrode is welded; c. The pre-melted slag is selected by mass ratio of 50% CaF2, 26% Al203, 19% CaO, and 5% MgO. The pre-melted slag accounts for 5% of the molten steel mass. The pre-melted slag is baked at 700℃ for 4h before the electroslag starts; d. Before the electroslag starts, argon is pre-charged. After the oxygen content in the crystallizer is lower than 3%, the arc striking starts. The electroslag remelting current is 11000A-9000A. The voltage is 38-42V. The melting speed is controlled to be 6.3-6.5kg / min.

[0059] S4, homogenization treatment

[0060] 00℃±30℃, holding for 1h; the temperature is raised to 950℃±15℃, the temperature rising time is ≥8h; 950℃±15℃, holding for 1h; the temperature is raised to 1160℃±10℃, the temperature rising time is ≥3h; 1160℃±10℃, maintaining for 30h; the temperature is raised to 1190℃±10℃, the temperature rising time is ≥3h; 1190℃±10℃, maintaining for 60h; the furnace is cooled to 700℃, and then the furnace is discharged for air cooling.

[0061] S5, hot forging breakdown

[0062] Breakdown: The first forging heating temperature is 1160℃±10℃, the open forging temperature is 1020℃±20℃, and the final forging temperature is 900℃±20℃; Breakdown forging, first light hammer forging, especially the head end, light forging, the amount of each time is controlled in 30-50mm, light hammer forging first breaks the surface grain, from the middle to the end, turn 90° in light hammer, when the electroslag ingot is forged into square, light hammer chamfering is carried out, and then the next step of square forging is carried out; The steel ingot needs two fires for each forging pass, φ400→240 square→180 square→100 square process, a total of 6 fire times; When the steel billet forging defects occur, stop further forging, and the defect part is ground or cut off; Square forging: 100 square rod is first ground to remove surface defects; After grinding is completed, 100 square is cut, and the cutting weight is controlled in 22-28kg; The forging heating temperature is 1170℃±10℃, the open forging temperature is 1050℃±20℃, and the final forging temperature is above 850℃; The forging adopts the principle of forging from the middle to the end, one end is first forged into shape, the other end is reheated, and the forged section is placed outside the furnace; After forging is completed, chamfering is carried out at both ends to facilitate subsequent rolling. After the square steel is cooled, UT detection and polishing treatment are carried out. Remark: The grain size of the square steel after forging is controlled to be greater than or equal to 10 levels.

[0063] 00Cr27Ni31Mo7CuN contains 6% Mo and 0.2% N, so the deformation resistance of the material is large, and the thermal conductivity coefficient is low. And under the as-cast structure, the hot plasticity of the material is very poor, and it cannot be formed by ingot hot rolling, and must be broken into forged structure from as-cast structure to greatly improve the hot plasticity of the steel. The forging heating process includes low temperature heating in the early stage and high temperature homogenization treatment in the middle and late stage, the heating speed of the low temperature heating in the early stage is controlled to be 100℃ / H, the low temperature heating in the early stage is slowly heated to avoid thermal stress caused by rapid heating, and the high temperature homogenization treatment in the middle and late stage is 1200℃ for 25h, which is mainly because the 00Cr27Ni31Mo7CuN alloy has high composition, and composition segregation will occur in the center during mold casting solidification, and a large amount of harmful phase (high Cr and Mo) will be precipitated at the segregation position during hot forming, which will affect the hot working property and corrosion resistance of the material. A large amount of precipitated phase exists in the center of the forged round without homogenization treatment, as shown in FIG. 1. In order to reduce the influence of segregation on the performance of the product, high temperature homogenization treatment is introduced, the elements are fully diffused through long time heat preservation, the internal element segregation is improved, the problem caused by harmful phase during subsequent hot forming is avoided, and the corrosion resistance of the finished product is improved. Figure 1

[0064] S6, rolling peeling

[0065] It is divided into two times; the first time obtains φ23mm round steel; the second time obtains φ21mm round steel. ​

[0066] Before rolling, the softening solution is prepared at 1150℃±10℃ and held for 1 hour to soften the material and inhibit grain growth; the finished product is prepared at 1180℃±10℃ and held for 1 hour.

[0067] S7, Centerless Grinding

[0068] A centerless ground round bar of 00Cr27Ni31Mo7CuN was obtained.

[0069] The method for obtaining alloy key pins by centerless grinding of round bars is as follows:

[0070] S11, Scrolling Cold Drawing

[0071] The centerless grinding round bar is first softened and solution treated at 1160℃±10℃ for 1 hour, and then passed through the rectangular die hole of the rolling die to obtain a square bar. The cross-sectional ratio of the bar before and after deformation by the rolling die is 12%-15%.

[0072] The rolling die uses two pairs of rotating rollers, such as Figure 4 As shown, one pair of rollers 1 are distributed vertically (the roller axes extend horizontally to the left and right), and the other pair of rollers 1 are distributed horizontally (the roller axes extend vertically). A rectangular die hole 1a is formed between the rolling surfaces of the two pairs of rollers. Through the development of the rolling cold drawing process, the bar stretching deformation process is relatively continuous and stable, which can reduce the formation of stress concentration and reduce the risk of bar fracture. The process of smoothly transforming the material from a circle to a square is successfully realized. The yield rate of this process is 98%, which ensures a good surface in the subsequent cold drawing and shaping process.

[0073] Existing hot rolling processes also use V-groove rollers. However, the 00Cr27Ni31Mo7CuN alloy of this application has a Cr content of 26.4% in the raw material, resulting in high cold working strength. During the deformation process of passing through a pair of V-grooves, the forces exerted on both sides of the V-grooves can cause the roller to break. In contrast, the unique design of the rolling die in this application results in a flat roller that does not require the machining of V-grooves, thus providing high strength. Furthermore, the roller is subjected to vertical forces acting on the roller shaft, making it less prone to deformation.

[0074] In addition, if the cold drawing process is used directly, many steps are required, the deformation amount can only be 5% each time, solution treatment is required for each deformation step, the head needs to be re-tied after each drawing, and 20cm of material is cut off each time, resulting in low mass production efficiency. However, this application only requires rolling cold drawing in S10 and cold drawing shaping in S11 (first shaping mold and second shaping mold), which greatly improves the mass production efficiency.

[0075] S12, Cold drawing and shaping

[0076] The square bar is sequentially passed through the first and second shaping molds to obtain a finished product with a shaped cross section, and the first and second shaping molds 2 are provided with a shaping mold hole 2a passing through front and back as shown in Figure 5 .

[0077] The square bar has a front and back cross section ratio of 8%-12% and 12%-15% before and after deformation by the first and second shaping molds

[0078] S11, S12, softening and solid solution before cold drawing, 1160℃±10℃, 1h holding; solid solution after cold drawing, 1160℃±10℃, 1h holding.

[0079] S13, fine polishing

[0080] The bar is conveyed by a roller conveying mechanism, and is polished on the front and back sidewalls and the upper and lower sidewalls by a pair of horizontally distributed grinding wheels and a pair of vertically distributed grinding wheels, without clamping operation.

[0081] S14, fine calibration

[0082] S15, sizing

[0083] The performance test data of the finished product of the 00Cr27Ni31Mo7CuN alloy key pin are as follows:

[0084] A. Grain size: 10.0 grade, see Figure 2 .

[0085] B. Non-metallic inclusions:

[0086] Judgment criteria:

[0087] A class: (fine) ≤1.0 grade (coarse) ≤1.0 grade;

[0088] B class: (fine) ≤1.0 grade (coarse) ≤1.0 grade;

[0089] C class: (fine) ≤1.0 grade (coarse) ≤1.0 grade;

[0090] D class: (fine) ≤1.0 grade (coarse) ≤1.0 grade.

[0091] Test value:

[0092] A class: (fine) 0 grade (coarse) 0 grade;

[0093] B class: (fine) 0 grade (coarse) 0 grade;

[0094] C class: (fine) 0 grade (coarse) 0 grade;

[0095] D class: (fine) 1.0 grade (coarse) 0 grade;

[0096] Reference is made to Figure 3 .

[0097] C. Hardness HB:

[0098] Test values: 280 / 283 / 282.

[0099] It is to be noted that, in the present text, relational terms such as first and second and the like can only be used to distinguish one entity or action from another entity or action, without necessarily requiring or implying any actual such relationship or order between or among the entities or actions. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises... a" does not, without more constraints, exclude the presence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0100] The above embodiments are only used to illustrate the technical solutions of the present application, not to limit it; although the above-mentioned embodiments of the present application have been described in detail, those skilled in the art should understand: it can still modify the technical solutions recorded in the above-mentioned embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for manufacturing a 00Cr27Ni31Mo7CuN alloy key pin, characterized in that, The raw material for this manufacturing method is a 00Cr27Ni31Mo7CuN centerless grinding round bar. The chemical composition of the 00Cr27Ni31Mo7CuN centerless grinding round bar, by mass percentage, includes C 0.012%, P 0.015%, S 0.001%, Cr 26.4%, Ni 30.9%, Mn 1.42%, Si 0.04%, Mo 6.19%, Cu 1.10%, N 0.20%, with the balance being Fe and unavoidable impurities. The manufacturing method includes the following steps: S11. Rolling cold drawing: A centerless ground round bar passes through the rectangular die hole of a rolling die to obtain a square bar. The rolling die uses two pairs of rotating rollers, one pair of rollers is distributed vertically and the other pair of rollers is distributed horizontally. A rectangular die hole is formed between the rolling surfaces of the two pairs of rollers. S12, cold drawing and shaping: the square bar passes through the first shaping mold and the second shaping mold in sequence to obtain the finished product with a shaped cross section; S13, fine polishing; S14, meticulous proofreading; S15, fixed length; in, In step S11, the ratio of the cross-section of the bar before and after deformation by the rolling die is 12%-15%; In step S12, the cross-sectional ratios of the bar before and after deformation by the first and second shaping molds are 8%-12% and 12%-15%, respectively.

2. The manufacturing method of a 00Cr27Ni31Mo7CuN alloy key pin as described in claim 1, characterized in that: in, For S11 and S12 bars, softening and solution treatment are performed before cold drawing at 1160℃±10℃ for 1 hour; solution treatment is performed after cold drawing, followed by a 1 hour holding period at 1160℃±10℃.

3. The manufacturing method of a 00Cr27Ni31Mo7CuN alloy key pin as described in claim 1, characterized in that: The manufacturing method of centerless grinding round bar is as follows: S1, Ingredients, S2 and VIM vacuum degassing control: The raw materials after S1 batching are added to the VIM vacuum degassing furnace, melted, and smelted using the single slag method. The slag material is selected according to the mass ratio of 50% CaO, 26% Al2O3, 19% MgO, and 5% SiO2. The first-stage decarburization control argon-oxygen ratio is 4:1, and the average decarburization rate in the first stage is 0.0125% / min. The second-stage decarburization control argon-oxygen ratio is 2:1, and the average decarburization rate in the second stage is 0.0188% / min. S3, ESR electroslag remelting, the pre-melted slag is selected according to the mass ratio of 50% CaF2, 26% Al2O3, 19% CaO, 5% MgO, pre-filled with argon gas, and the arc is started after the oxygen content in the crystallizer is lower than 3%. The electroslag remelting current is 11000A-9000A, the voltage is 38-42V, and the melting rate is controlled at 6.3-6.5kg / min; S4. Homogenization treatment: 200℃±30℃, hold for 1 hour; heat to 950℃±15℃, hold for ≥8 hours; 950℃±15℃, hold for 1 hour; heat to 1160℃±10℃, hold for ≥3 hours; 1160℃±10℃, maintain for 30 hours; heat to 1190℃±10℃, hold for ≥3 hours; 1190℃±10℃, maintain for 60 hours; furnace cool to 700℃ and then air cool. S5. Hot forging blanking; S6. Rolling and peeling; S7, centerless grinding.

4. The manufacturing method of a 00Cr27Ni31Mo7CuN alloy key pin as described in claim 3, characterized in that: In step S2, after the molten steel is refined in the VIM vacuum degassing furnace, it is argon-blown and stirred to remove slag using a double bottom blowing system.

5. The manufacturing method of a 00Cr27Ni31Mo7CuN alloy key pin as described in claim 3, characterized in that: In step S3, before electroslag remelting, the vacuum electrode of the induction furnace is polished to clean the surface defects; and the electrode is baked at 600°C for 4 hours. After baking, a dummy electrode is welded.

6. The manufacturing method of a 00Cr27Ni31Mo7CuN alloy key pin as described in claim 1, characterized in that: In step S3, the pre-melted slag is baked at 700°C for 4 hours before the electroslag process begins.

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