Stainless steel heat treatment process

Abstract

The invention relates to the technical field of metal material machining, and particularly discloses a stainless steel heat treatment process. The invention relates to a stainless steel heat treatment process which comprises the following steps: under the protection of inert gas, heating a stainless steel forge piece to 460-500 DEG C, preserving heat, heating to 630-670 DEG C, preserving heat, heating to 740-780 DEG C, preserving heat, cooling to 510-550 DEG C, preserving heat and cooling; and heating the stainless steel forge piece to 440-480 DEG C under the magnetic field intensity of 110-150kA / m, preserving heat, cooling to 180-220 DEG C, preserving heat and cooling to obtain a magnetic stainless steel finished product. According to the heat treatment process for the stainless steel, through mutual cooperation of all the steps, on the basis that the mechanical property and the corrosion resistance are not affected, the magnetic conductivity is reduced, the coercive force and the saturation flux density are improved, the cost is low, and the practical value and the economic value are achieved.

Description

Technical Field

[0001] The present application relates to the technical field of metal material processing, and more specifically, to a stainless steel heat treatment process. Background Art

[0002] Metal materials are materials that are mainly composed of metal elements or metal elements and have metal properties, mainly including stainless steel, alloys, single metals, etc. Due to their unique physical and chemical properties, they are widely used in industrial production and scientific research, especially in the automotive, electronics, aerospace, chemical, medical equipment and other industries. With the advancement of science and technology, some metal materials have been used in electromagnetic equipment because of their good magnetic properties, such as magnetic stainless steel products. In the prior art, magnetic stainless steel products are generally made of ferritic stainless steel or martensitic stainless steel. In order to improve the magnetic properties of magnetic stainless steel products, such as reducing magnetic permeability and increasing coercivity, some researchers often add trace elements to the chemical composition of stainless steel. Although it can improve the magnetic properties, it generally has the problem of high cost, and there may also be the problem of sacrificing mechanical properties due to the introduction of trace elements. Summary of the invention

[0003] In order to reduce the magnetic permeability of magnetic stainless steel products and improve the coercivity of magnetic stainless steel products, the present application provides a stainless steel heat treatment process, which adopts the following technical solutions: A stainless steel heat treatment process comprises the following steps: S1. Under the protection of inert gas, heat the stainless steel forgings to 460-500℃ at a heating rate of 8-12℃ / min, keep them warm for 100-140min, heat them to 630-670℃, keep them warm for 70-110min, then heat them to 740-780℃ at a heating rate of 4-8℃ / min, keep them warm for 40-80min, cool them to 510-550℃, keep them warm for 40-80min, and cool them down; S2. Under a magnetic field strength of 110-150 kA / m, the stainless steel forging treated in step S1 is heated to 440-480° C., kept warm for 100-140 min, cooled to 180-220° C., kept warm for 20-40 min, and cooled to obtain a magnetic stainless steel product.

[0004] The stainless steel heat treatment process of the present application, through the mutual cooperation between each step, makes the obtained magnetic stainless steel finished product have a maximum magnetic permeability of less than 1850H / m, a coercive force of more than 93A / m, a saturation magnetic induction intensity of more than 1.5T, a tensile strength of more than 520MPa, and a neutral salt spray corrosion resistance time of more than 95h, showing the advantages of low magnetic permeability, high coercive force, good saturation magnetic induction intensity, high tensile strength, and good corrosion resistance, and has excellent magnetic properties, mechanical properties, and corrosion resistance. On the basis of not affecting the mechanical properties and corrosion resistance of the magnetic stainless steel finished product, the magnetic permeability is reduced, the coercive force and the saturation magnetic induction intensity are improved, the cost is low, and it has practical value and economic value, and meets market demand.

[0005] In the heat treatment process of the present application, a three-stage heating process is adopted, first heating to 460-500°C, then heating to 630-670°C, and then heating to 740-780°C. The temperature and time of each stage of heating are adjusted to improve the internal stress of the stainless steel forging, soften the organizational structure, refine the grains, improve the degree of crystallization, reduce the magnetic permeability, increase the coercive force, saturation magnetic induction intensity, tensile strength and neutral salt spray corrosion resistance time, so that the magnetic stainless steel finished product exhibits better comprehensive performance.

[0006] Optionally, the stainless steel forging is one of ferritic stainless steel and martensitic stainless steel.

[0007] By adopting the above technical solution, the material of the stainless steel forgings is limited, which facilitates the selection of the stainless steel forgings and ensures the stability of the magnetic stainless steel finished products.

[0008] Optionally, the stainless steel forging is ferritic stainless steel, which is mainly composed of the following chemical components in weight percentage: C: 0.05-0.08%, Cr: 16-18%, Si: 0.2-0.5%, Mn: 0.4-0.6%, Ni: 0.5-0.7%, Ti: 0.05-0.17%, Nb: 0.01-0.03%, P≤0.02%, S≤0.02%, and the rest is Fe and unavoidable impurities.

[0009] By adopting the above technical scheme, the chemical composition of ferritic stainless steel is optimized to ensure the stability of the source of ferritic stainless steel, which is not only convenient for heat treatment and processing of magnetic stainless steel products, but also makes the magnetic stainless steel products have good magnetic properties, mechanical properties and corrosion resistance. In multiple embodiments, ferritic stainless steel is mainly composed of the following chemical components in weight percentage: C: 0.06%, Cr: 17%, Si: 0.4%, Mn: 0.5%, Ni: 0.6%, Ti: 0.11%, Nb: 0.02%, P: 0.01%, S: 0.01%, and the rest is Fe and inevitable impurities. It can be set to the following chemical composition in weight percentage as needed: C: 0.05%, Cr: 16%, Si: 0.5%, Mn: 0.4%, Ni: 0.5%, Ti: 0.17%, Nb: 0.03%, P: 0.02%, S: 0.01%, and the rest is Fe and inevitable impurities. The ferritic stainless steel can be set to the following chemical composition in weight percentage as needed: C: 0.08%, Cr: 18%, Si: 0.2%, Mn: 0.6%, Ni: 0.7%, Ti: 0.05%, Nb: 0.01%, P: 0.01%, S: 0.02%, and the rest is Fe and inevitable impurities, but it is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0010] Optionally, the stainless steel forging is one of a ring, a bar, a plate, and a strip.

[0011] By adopting the above technical solution, the shape of the stainless steel forgings is limited so that they can better meet the needs of different application scenarios and increase the diversity of magnetic stainless steel finished products.

[0012] Optionally, the stainless steel forging is a ring material, and the outer diameter of the stainless steel forging is 5-10 mm, the wall thickness is 0.5-3 mm, and the height is 1-5 mm.

[0013] By adopting the above technical solution, the size of the stainless steel forging is limited, which not only facilitates the processing of the stainless steel forging, but also ensures the dimensional stability, so that it is heated evenly during the heat treatment process, ensuring the stability of the heat treatment process and the quality of the magnetic stainless steel finished product.

[0014] In multiple embodiments, the outer diameter of the stainless steel forging is 7.5 mm, the wall thickness is 1.5 mm, and the height is 3 mm. The outer diameter can be set to 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, and 10 mm as needed, but it is not limited to the listed values. Other values ​​not listed in the numerical range are also applicable. The wall thickness can also be set to 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, and 5 mm as needed, but it is not limited to the listed values. Other values ​​not listed in the numerical range are also applicable. The height can also be set to 1 mm, 2 mm, 4 mm, and 5 mm as needed, but it is not limited to the listed values. Other values ​​not listed in the numerical range are also applicable.

[0015] Optionally, the inert gas is one or more of nitrogen, argon and helium.

[0016] By adopting the above technical solution, the inert gas is optimized, which facilitates the selection of the inert gas. Moreover, nitrogen, argon and helium can all play a good protective role on the stainless steel forgings during the heat treatment process, avoid oxidation and decarburization, and ensure the mechanical properties of the magnetic stainless steel products.

[0017] In many embodiments, the inert gas is nitrogen. The inert gas can be selected as argon or helium as needed, but is not limited to the listed options. Other options not listed within the selection range are also applicable.

[0018] Optionally, in step S1, the temperature is lowered to 510-550°C at a cooling rate of 12-16°C / min.

[0019] By adopting the above technical scheme, the cooling rate is limited, and the excessive internal stress or cracks in the stainless steel forgings during the cooling process are reduced, which helps to maintain the integrity, mechanical properties and corrosion resistance of the stainless steel forgings and improve the quality of magnetic stainless steel products.

[0020] Optionally, in step S2, the temperature is increased to 440-480°C at a heating rate of 3-7°C / min.

[0021] By adopting the above technical solution, in the presence of a magnetic field, the temperature is slowly increased, which can not only effectively reduce the excessive internal stress or cracks caused by the rapid increase in temperature, but also ensure that the stainless steel forgings are uniformly magnetized and fully magnetized, which helps to improve the saturation magnetic induction intensity of the stainless steel forgings.

[0022] Optionally, in step S2, the temperature is lowered to 180-220°C at a cooling rate of 1-5°C / min.

[0023] By adopting the above technical scheme, in the presence of a magnetic field, the temperature is slowly cooled, thereby reducing the disorder of the magnetic domain structure or the reversal of the magnetic moment caused by a sharp drop in temperature. This helps the stainless steel forgings to maintain the magnetized state during the cooling process, thereby ensuring the stability of the magnetic properties and mechanical properties of the magnetic stainless steel products.

[0024] Optionally, in step S1, during the cooling process, the cooling method is air cooling, and the cooling end point is room temperature; in step S2, during the cooling process, the cooling method is air cooling, and the cooling end point is room temperature.

[0025] By adopting the above technical solution, air cooling is adopted in both step S1 and step S2, which is easy to operate and effectively reduces the processing cost, and is suitable for large-scale industrial batch production applications.

[0026] Optionally, a magnetic stainless steel finished product is obtained by processing using the stainless steel heat treatment process described above.

[0027] In summary, this application has at least the following beneficial effects: In the heat treatment process of the present application, by adopting three-stage heating, first heating to 460-500°C, then heating to 630-670°C, and then heating to 740-780°C, the temperature and time of each stage heating are adjusted to improve internal stress, soften the organizational structure, refine the grains, improve the degree of crystallization, reduce the magnetic permeability, and improve the coercive force, saturation magnetic induction intensity, tensile strength and neutral salt spray corrosion resistance time. And make the maximum magnetic permeability of the magnetic stainless steel product <1850H / m, coercive force>93A / m, saturation magnetic induction intensity>1.5T, tensile strength>520MPa, neutral salt spray corrosion resistance time>95h, without affecting the mechanical properties and corrosion resistance of the magnetic stainless steel product, reduce the magnetic permeability, improve the coercive force and saturation magnetic induction intensity, low cost, practical value and economic value, meet market demand. DETAILED DESCRIPTION

[0028] In order to make the present application easier to understand, the present application will be further described in detail below in conjunction with the examples, which are merely illustrative and are not intended to limit the scope of application of the present application. The raw materials or components used in the present application can be obtained through commercial routes or conventional methods unless otherwise specified. Example

[0029] Example 1 A stainless steel heat treatment process comprises the following steps: S1. Under nitrogen protection, the stainless steel forgings were heated to 480℃ at a heating rate of 10℃ / min, kept warm for 120min, then heated to 650℃, kept warm for 90min, then heated to 760℃ at a heating rate of 6℃ / min, kept warm for 60min, then cooled to 530℃ at a cooling rate of 15℃ / min, kept warm for 60min. Then cooled to 23℃ by air cooling.

[0030] Among them, the stainless steel forging is a ring material, and the outer diameter of the stainless steel forging is 7.5mm, the wall thickness is 1.5mm, and the height is 3mm. The stainless steel forging is ferritic stainless steel, and the ferritic stainless steel is mainly composed of the following chemical components in weight percentage: C: 0.06%, Cr: 17%, Si: 0.4%, Mn: 0.5%, Ni: 0.6%, Ti: 0.11%, Nb: 0.02%, P: 0.01%, S: 0.01%, and the rest is Fe and unavoidable impurities.

[0031] S2. In a magnetic field with a strength of 130 kA / m, the stainless steel forging treated in step S1 is heated to 460°C at a heating rate of 5°C / min, and kept at this temperature for 120 min, and then cooled to 200°C at a cooling rate of 3°C / min, and kept at this temperature for 30 min. Then, the forging is cooled to 23°C by air cooling to obtain a magnetic stainless steel product.

[0032] Example 2 A stainless steel heat treatment process, which differs from Example 1 in that, in step S1, the stainless steel forgings have the same source but different treatment processes.

[0033] The specific treatment process of step S1 is as follows: S1. Under nitrogen protection, the stainless steel forging is heated to 460°C at a heating rate of 8°C / min, and kept at this temperature for 140min, then heated to 630°C, and kept at this temperature for 110min, then heated to 740°C at a heating rate of 4°C / min, and kept at this temperature for 80min, then cooled to 510°C at a cooling rate of 12°C / min, and kept at this temperature for 80min. Then, it is cooled to 23°C by air cooling.

[0034] Example 3 A stainless steel heat treatment process, which differs from Example 1 in that, in step S1, the stainless steel forgings have the same source but different treatment processes.

[0035] The specific treatment process of step S1 is as follows: under nitrogen protection, the stainless steel forging is heated to 500°C at a heating rate of 12°C / min, and kept at this temperature for 100 minutes, then heated to 670°C, and kept at this temperature for 70 minutes, then heated to 780°C at a heating rate of 8°C / min, and kept at this temperature for 40 minutes, then cooled to 550°C at a cooling rate of 16°C / min, and kept at this temperature for 40 minutes. Then, it is cooled to 23°C by air cooling.

[0036] Example 4 A stainless steel heat treatment process, which is different from Example 1 in that step S2 is different.

[0037] Step S2 specifically includes: heating the stainless steel forging after the treatment in step S1 to 440°C at a heating rate of 3°C / min under a magnetic field strength of 110 kA / m, keeping the temperature for 140 minutes, cooling the temperature to 180°C at a cooling rate of 1°C / min, keeping the temperature for 40 minutes. Then, cooling the stainless steel forging to 23°C by air cooling to obtain a magnetic stainless steel product.

[0038] Example 5 A stainless steel heat treatment process, which is different from Example 1 in that step S2 is different.

[0039] Step S2 specifically includes: heating the stainless steel forging after the treatment in step S1 to 480°C at a heating rate of 7°C / min under a magnetic field strength of 150 kA / m, keeping the temperature for 100 min, cooling the temperature to 220°C at a cooling rate of 5°C / min, keeping the temperature for 20 min. Then, cooling the stainless steel forging to 23°C by air cooling to obtain a magnetic stainless steel product.

[0040] Comparative Example Comparative Example 1 A stainless steel heat treatment process, which differs from Example 1 in that, in step S1, the stainless steel forgings have the same source but different treatment processes.

[0041] The specific treatment process of step S1 is: under nitrogen protection, the stainless steel forging is heated to 760°C at a heating rate of 10°C / min, kept at this temperature for 180 minutes, cooled to 530°C at a cooling rate of 15°C / min, kept at this temperature for 60 minutes, and then cooled to 23°C by air cooling.

[0042] Comparative Example 2 A stainless steel heat treatment process, which differs from Example 1 in that, in step S1, the stainless steel forgings have the same source but different treatment processes.

[0043] The specific treatment process of step S1 is: under nitrogen protection, the stainless steel forging is heated to 760°C at a heating rate of 6°C / min, kept at this temperature for 180 minutes, cooled to 530°C at a cooling rate of 15°C / min, kept at this temperature for 60 minutes, and then cooled to 23°C by air cooling.

[0044] Comparative Example 3 A stainless steel heat treatment process, which differs from Example 1 in that, in step S1, the stainless steel forgings have the same source but different treatment processes.

[0045] The specific treatment process of step S1 is as follows: under nitrogen protection, the stainless steel forging is heated to 650°C at a heating rate of 10°C / min, and kept at this temperature for 210 minutes, then heated to 760°C at a heating rate of 6°C / min, and kept at this temperature for 60 minutes, then cooled to 530°C at a cooling rate of 15°C / min, and kept at this temperature for 60 minutes. Then, it is cooled to 23°C by air cooling.

[0046] Comparative Example 4 A stainless steel heat treatment process, which differs from Example 1 in that, in step S1, the stainless steel forgings have the same source but different treatment processes.

[0047] The specific treatment process of step S1 is as follows: under nitrogen protection, the stainless steel forging is heated to 480°C at a heating rate of 10°C / min, and kept at this temperature for 210 minutes, then heated to 760°C at a heating rate of 6°C / min, and kept at this temperature for 60 minutes, then cooled to 530°C at a cooling rate of 15°C / min, and kept at this temperature for 60 minutes. Then, it is cooled to 23°C by air cooling.

[0048] Comparative Example 5 A stainless steel heat treatment process, which differs from Example 1 in that, in step S1, the stainless steel forgings have the same source but different treatment processes.

[0049] The specific treatment process of step S1 is as follows: under nitrogen protection, the stainless steel forging is heated to 480°C at a heating rate of 10°C / min, and kept at this temperature for 120min, then heated to 650°C, and kept at this temperature for 90min, then heated to 720°C at a heating rate of 6°C / min, and kept at this temperature for 60min, then cooled to 530°C at a cooling rate of 15°C / min, and kept at this temperature for 60min. Then, it is cooled to 23°C by air cooling.

[0050] Comparative Example 6 A stainless steel heat treatment process, which differs from Example 1 in that, in step S1, the stainless steel forgings have the same source but different treatment processes.

[0051] The specific treatment process of step S1 is as follows: under nitrogen protection, the stainless steel forging is heated to 480°C at a heating rate of 10°C / min, and kept at this temperature for 120 minutes, then heated to 650°C, and kept at this temperature for 90 minutes, then heated to 800°C at a heating rate of 6°C / min, and kept at this temperature for 60 minutes, then cooled to 530°C at a cooling rate of 15°C / min, and kept at this temperature for 60 minutes. Then, it is cooled to 23°C by air cooling.

[0052] Comparative Example 7 A stainless steel heat treatment process, which differs from Example 1 in that, in step S1, the stainless steel forgings have the same source but different treatment processes.

[0053] The specific treatment process of step S1 is as follows: under nitrogen protection, the stainless steel forging is heated to 480°C at a heating rate of 10°C / min, and kept at this temperature for 120 minutes, then heated to 650°C, and kept at this temperature for 90 minutes, then heated to 760°C at a heating rate of 6°C / min, and kept at this temperature for 20 minutes, then cooled to 530°C at a cooling rate of 15°C / min, and kept at this temperature for 60 minutes. Then, it is cooled to 23°C by air cooling.

[0054] Comparative Example 8 A stainless steel heat treatment process, which differs from Example 1 in that, in step S1, the stainless steel forgings have the same source but different treatment processes.

[0055] The specific treatment process of step S1 is as follows: under nitrogen protection, the stainless steel forging is heated to 480°C at a heating rate of 10°C / min, and kept at this temperature for 120 minutes, then heated to 650°C, and kept at this temperature for 90 minutes, then heated to 760°C at a heating rate of 6°C / min, and kept at this temperature for 100 minutes, then cooled to 530°C at a cooling rate of 15°C / min, and kept at this temperature for 60 minutes. Then, it is cooled to 23°C by air cooling.

[0056] Performance Testing (1) The magnetic stainless steel products obtained in Examples 1-5 and Comparative Examples 1-8 were respectively taken and the maximum magnetic permeability, coercive force and saturation magnetic induction intensity of the magnetic stainless steel products were tested using a hysteresis loop measuring instrument. The test results are shown in Table 1.

[0057] (2) The magnetic stainless steel products obtained in Examples 1-5 and Comparative Examples 1-8 were respectively taken, and the tensile strength and neutral salt spray corrosion resistance time of the magnetic stainless steel products were tested according to GB / T 228.1-2021 and GB / T10125-2012. The test results are shown in Table 1.

[0058] Table 1 Test results As can be seen from Table 1, the magnetic stainless steel product obtained by the stainless steel heat treatment process of the present application has a low maximum magnetic permeability, which is 1802-1808H / m. It also has high coercive force and saturation magnetic induction intensity, with a coercive force of 93.6-94.8A / m and a saturation magnetic induction intensity of 1.52-1.55T. At the same time, it also has high tensile strength and neutral salt spray corrosion resistance time, with a tensile strength of 521-529MPa and a neutral salt spray corrosion resistance time of 95.7-98.4h. Through the mutual cooperation between the various steps of the present application, the magnetic stainless steel product has the advantages of low magnetic permeability, high coercive force, good saturation magnetic induction intensity, high tensile strength and good corrosion resistance, showing excellent magnetic properties, mechanical properties and corrosion resistance, with good comprehensive performance, meeting market demand.

[0059] Comparative Examples 1-2 are compared. In step S1 of the heat treatment process of Comparative Example 1, a one-stage heating is used to heat the product to 760°C at a heating rate of 10°C / min; in step S1 of the heat treatment process of Comparative Example 2, a one-stage heating is used to heat the product to 760°C at a heating rate of 6°C / min. It can be seen that in step S1, the slow heating method is used to help improve the performance of the magnetic stainless steel product.

[0060] Compare Example 1 with Comparative Examples 3-4. In step S1 of the heat treatment process of Comparative Example 3, two-stage heating is adopted, first heating to 650°C and then heating to 760°C; in step S1 of the heat treatment process of Comparative Example 4, two-stage heating is adopted, first heating to 480°C and then heating to 760°C; in step S1 of the heat treatment process of Example 1, three-stage heating is adopted, first heating to 480°C, then heating to 650°C, and then heating to 760°C. It can be seen that in step S1, the three-stage heating is adopted, which can effectively eliminate the internal stress of the stainless steel forgings, soften the organizational structure, refine the organization, reduce the maximum magnetic permeability, and improve the coercive force, saturation magnetic induction intensity, tensile strength and corrosion resistance.

[0061] Compare Example 1 with Comparative Examples 5-6. In step S1 of the heat treatment process of Comparative Example 5, three stages of heating are adopted, and the third stage is heated to 720°C; in step S1 of the heat treatment process of Comparative Example 6, three stages of heating are adopted, and the third stage is heated to 800°C; in step S1 of the heat treatment process of Example 1, three stages of heating are adopted, and the third stage is heated to 760°C. It can be seen from this that the temperature of the third stage of heating treatment is outside the range of 740-780°C, which is not conducive to the heat treatment of stainless steel forgings. This is mainly because the temperature of the third stage of heating treatment affects the degree of crystallization, grain size and uniformity, thereby affecting the quality of the magnetic stainless steel product, and the temperature of the third stage of heating treatment is within the range of 740-780°C, which can make the magnetic stainless steel product exhibit higher saturation magnetic induction intensity, tensile strength and corrosion resistance.

[0062] Compare Example 1 with Comparative Examples 7-8. In step S1 of the heat treatment process of Comparative Example 7, three stages of heating are adopted, and the third stage is heated to 760°C, and the heat preservation treatment is carried out for 20 minutes; in step S1 of the heat treatment process of Comparative Example 8, three stages of heating are adopted, and the third stage is heated to 760°C, and the heat preservation treatment is carried out for 100 minutes; in step S1 of the heat treatment process of Example 1, three stages of heating are adopted, and the third stage is heated to 760°C, and the heat preservation treatment is carried out for 60 minutes. It can be seen that the heat preservation time of the third stage of heating treatment is within the range of 40-80 minutes, which is beneficial to the heat treatment of stainless steel forgings and enables the magnetic stainless steel finished product to exhibit better comprehensive performance.

[0063] It should be noted that the embodiments described above are only used to explain the present application and do not constitute any limitation to the present application. The present application is described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present application may be modified as specified within the scope of the claims of the present application, and the present invention may be revised without departing from the scope and spirit of the present application. Although the present application described therein relates to specific methods, materials and embodiments, it does not mean that the present application is limited to the specific examples disclosed therein. On the contrary, the present application can be extended to all other methods and applications with the same functions.

Claims

1. A stainless steel heat treatment process, characterized in that: The steps include: S1. Under the protection of inert gas, heat the stainless steel forgings to 460-500℃ at a heating rate of 8-12℃ / min, keep them warm for 100-140min, heat them to 630-670℃, keep them warm for 70-110min, then heat them to 740-780℃ at a heating rate of 4-8℃ / min, keep them warm for 40-80min, cool them to 510-550℃, keep them warm for 40-80min, and cool them down; S2. Under a magnetic field strength of 110-150 kA / m, the stainless steel forging treated in step S1 is heated to 440-480° C., kept warm for 100-140 min, cooled to 180-220° C., kept warm for 20-40 min, and cooled to obtain a magnetic stainless steel product.

2. A stainless steel heat treatment process according to claim 1, characterized in that: The stainless steel forging is one of ferritic stainless steel and martensitic stainless steel.

3. A stainless steel heat treatment process according to claim 1, characterized in that: The stainless steel forging is ferritic stainless steel, which is mainly composed of the following chemical components in weight percentage: C: 0.05-0.08%, Cr: 16-18%, Si: 0.2-0.5%, Mn: 0.4-0.6%, Ni: 0.5-0.7%, Ti: 0.05-0.17%, Nb: 0.01-0.03%, P≤0.02%, S≤0.02%, and the rest is Fe and unavoidable impurities.

4. A stainless steel heat treatment process according to claim 1, characterized in that: The stainless steel forging is one of a ring material, a bar material, a plate material and a strip material.

5. A stainless steel heat treatment process according to claim 1, characterized in that: The stainless steel forging is a ring material, and the outer diameter of the stainless steel forging is 5-10 mm, the wall thickness is 0.5-3 mm, and the height is 1-5 mm.

6. A stainless steel heat treatment process according to claim 1, characterized in that: The inert gas is one or more of nitrogen, argon and helium.

7. A stainless steel heat treatment process according to claim 1, characterized in that: In step S1, the temperature is lowered to 510-550°C at a cooling rate of 12-16°C / min.

8. A stainless steel heat treatment process according to claim 1, characterized in that: In step S2, the temperature is increased to 440-480°C at a heating rate of 3-7°C / min.

9. A stainless steel heat treatment process according to claim 1, characterized in that: In step S2, the temperature is lowered to 180-220°C at a cooling rate of 1-5°C / min.

10. A stainless steel heat treatment process according to claim 1, characterized in that: In step S1, during the cooling process, the cooling method is air cooling, and the cooling end point is room temperature; in step S2, during the cooling process, the cooling method is air cooling, and the cooling end point is room temperature.

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