CN-117626166-B - Surface nitriding hardening method for high-nitrogen martensitic stainless steel and high-nitrogen martensitic stainless steel

Abstract

The invention discloses a surface nitriding super-hardening method of high-nitrogen martensitic stainless steel and high-nitrogen martensitic stainless steel, belongs to the technical field of stainless steel, and solves one of the problems that the high-nitrogen martensitic stainless steel in the prior art still cannot meet the requirements of high wear resistance and high temperature resistance. The surface nitriding superhard method for the high-nitrogen martensitic stainless steel comprises the steps of step 1, spheroidizing treatment and quenching tempering treatment, step 2, long-time surface nitriding treatment, nitriding time being more than 25 hours, and step3, tissue stabilizing tempering. The high-nitrogen martensitic stainless steel prepared by the method has high hardness, good wear resistance and good high temperature resistance.

Inventors

• CAO WENQUAN
• XU HAIFENG
• WANG HUI
• WANG CUNYU
• YU FENG
• LIANG JIANXIONG
• WENG YUQING

Assignees

• 钢铁研究总院有限公司

Dates

Publication Date

20260508

Application Date

20240103

Claims (5)

1. 1. A method of super hardening a high nitrogen martensitic stainless steel surface by nitriding, comprising: Step 1, spheroidizing and quenching tempering; step 2, surface nitriding treatment for a long time, wherein the nitriding treatment parameters are 550 ℃ multiplied by 30h; step 3, tissue stabilization tempering; the high-nitrogen martensitic stainless steel comprises the following components in percentage by mass, wherein the balance of ：C：0.25%~0.35%, Si≤1.00%,Mn≤1.00%,Cr：14.0%~16.0%,S：≤0.01%,P：≤0.02%,Ni≤0.3%,Mo：0.85%~1.10%,N：0.30%~0.50%, is Fe and unavoidable trace impurities; in the step 1, the step of spheroidizing includes: Step 101, placing a high-nitrogen martensitic stainless steel bar material into a heating furnace, heating to 860-880 ℃, and preserving heat for 3.5-4.5 hours; 102, cooling to 725-735 ℃ and preserving heat for 3.5-4.5 hours; step 103, cooling to below 550 ℃ and discharging for air cooling; in the step 102, the cooling rate is controlled to be 28-32 ℃ per hour; in the step 103, the cooling rate is controlled to be 28-32 ℃ per hour; in the step 103, the structure of the bar obtained after air cooling is ferrite and uniformly distributed spherical carbide, wherein more than 95% of spherical carbide has the size of 0.3-1.5 mu m; in the step 1, the quenching and tempering treatment step comprises the following steps: 104, carrying out oil quenching on the bar processed in the step 103 to room temperature after heat preservation at 1025-1035 ℃ for 1-2 hours; Step 105, carrying out cold treatment on the bar at-70 to-75 ℃ for 1-3 hours; 106, preserving the temperature of the bar at 140-160 ℃ for 3-5 hours; the structure of the bar obtained after the treatment in the step 106 is a high-nitrogen martensitic structure with fine original austenite and uniformly distributed carbides, wherein the average grain size of the original austenite is 8-12 mu m, and the size of the carbide with the maximum diameter is not more than 5 mu m; In the step 3, the depth of a nitriding layer of the high-nitrogen martensitic stainless steel bar after the structure stabilization tempering is 0.1-0.2 mm, a surface microstructure is a nitride structure, and a core microstructure is tempered troostite; The high-nitrogen martensitic stainless steel has good high temperature resistance.
2. 2. The method for nitriding super-hardening the surface of the high-nitrogen martensitic stainless steel according to claim 1, wherein in the step 102, the cooling rate is controlled to be 28-30 ℃ per hour.
3. 3. The method for nitriding super-hardening the surface of the high-nitrogen martensitic stainless steel according to claim 1, wherein in the step 103, the cooling rate is controlled to be 28-30 ℃ per hour.
4. 4. A surface nitriding super-hardening method for high-nitrogen martensitic stainless steel according to any one of claims 1 to 3, wherein in the step 3, the step of tissue stabilization tempering includes heat preservation at 500-650 ℃ for 2-4 hours.
5. 5. A high nitrogen martensitic stainless steel, characterized in that it is produced by the method according to any one of claims 1 to 4.

Description

Surface nitriding hardening method for high-nitrogen martensitic stainless steel and high-nitrogen martensitic stainless steel Technical Field The invention relates to the technical field of stainless steel, in particular to a surface nitriding super-hardening method of high-nitrogen martensitic stainless steel and the high-nitrogen martensitic stainless steel. Background The high-nitrogen martensitic stainless steel has excellent corrosion resistance, temperature resistance and fatigue resistance, and has wide application prospects in the fields of bearings, gears, lead screws, guide rails and the like. The surface hardness of the high-nitrogen martensitic stainless steel G30Cr15Mo1N with excellent corrosion resistance is not higher than 60HRC, and the hardness at 350 ℃ is only 56HRC, and the requirements of high wear resistance, fatigue resistance and high temperature resistance can not be met. Therefore, how to improve the wear resistance, fatigue resistance and high temperature resistance of high nitrogen martensitic stainless steel is a problem to be solved. Disclosure of Invention In view of the above, the present invention aims to provide a surface nitriding super hardening method for high nitrogen martensitic stainless steel and high nitrogen martensitic stainless steel, which are used for solving the problem that the existing high nitrogen martensitic stainless steel still cannot meet the requirements of high wear resistance and high temperature resistance. The aim of the invention is mainly realized by the following technical scheme: In one aspect, the invention provides a method for superhard nitriding of a high-nitrogen martensitic stainless steel surface, comprising the following steps: Step 1, spheroidizing and quenching tempering; Step 2, surface nitriding treatment for a long time, wherein nitriding time is more than 25 hours; And 3, tissue stabilization tempering. Further, in step 1, the step of spheroidizing includes: Step 101, placing a high-nitrogen martensitic stainless steel bar material into a heating furnace, heating to 860-880 ℃, and preserving heat for 3.5-4.5 hours; 102, cooling to 725-735 ℃ and preserving heat for 3.5-4.5 hours; and 103, cooling to below 550 ℃ and discharging for air cooling. Further, in step 102, the cooling rate is controlled to be 28-32 ℃ per hour. Further, in step 103, the cooling rate is controlled to be 28-32 ℃ per hour. Further, in step 103, the structure of the rod obtained after air cooling is ferrite+uniformly distributed spherical carbide. Further, in step1, the step of quenching and tempering treatment includes: 104, carrying out oil quenching on the bar processed in the step 103 to room temperature after heat preservation at 1025-1035 ℃ for 1-2 hours; Step 105, carrying out cold treatment on the bar at-70 to-75 ℃ for 1-3 hours; and 106, preserving the temperature of the bar at 140-160 ℃ for 3-5 hours. Further, the structure of the bar obtained after the treatment in the step 106 is a high-nitrogen martensitic structure with fine original austenite and uniformly distributed carbide. Further, in the step 2, the step of nitriding the surface for a long time comprises nitriding treatment at 530-560 ℃ for 20-30 hours. Further, in the step 3, the step of tissue stabilization tempering comprises the step of heat preservation for 2-4 hours at 500-650 ℃. The invention also provides the high-nitrogen martensitic stainless steel, which is prepared by adopting the method. Compared with the prior art, the invention can at least realize one of the following beneficial effects: According to the surface nitriding super-hardening method for the high-nitrogen martensitic stainless steel, the initial structure which is thinned and homogenized is obtained through spheroidizing treatment and quenching tempering treatment, and then the final structure stabilizing tempering is combined through long-time surface nitriding treatment, so that the obtained high-nitrogen martensitic stainless steel has high surface hardness, surface hardness of more than or equal to 62HRC, for example, 62-70 HRC, high hardness, good wear resistance and good fatigue resistance. The sequence of each step and the accurate control of each technological parameter in the surface nitriding superhard method of the high-nitrogen martensitic stainless steel can ensure that a refined and homogenized initial structure is obtained, a good structure preparation is laid for the surface nitriding of the high-nitrogen martensitic stainless steel, the thickness of a nitriding layer of the final high-nitrogen martensitic stainless steel is 0.1-0.2 mm, the surface hardness of a high-nitrogen martensitic stainless steel bar is more than or equal to 62HRC, for example, 62-70 HRC, the hardness is high, the wear resistance is good, the fatigue resistance is good, and the hardness of the high-nitrogen martensitic stainless steel can still be kept above 62HRC after the high-nitrogen martensitic stainless steel is temper