Precipitation-hardened martensite stainless steel and preparation method thereof

Abstract

The invention relates to precipitation-hardened martensite stainless steel and a preparation method thereof, and belongs to the technical field of materials. The precipitation-hardened martensite stainless steel comprises, by weight, 0.14%-0.20% of C, 13.0%-16.0% of Cr, 12.0%-15.0% of Co, 4.5%-5.5% of Mo, 0.5%-2.0% of Ni, 0.40%-0.60% of V, no more than 0.5% of Mn, no more than 0.1% of Si, less than 0.01% of P, less than 0.01% of S, less than 0.01% of O, no more than 0.1% of N, and the balance ferrum. The preparation method of the precipitation-hardened martensite stainless steel comprises thesteps of material proportioning, smelting, molding by casting, forging and heat treatment. According to the precipitation-hardened martensite stainless steel and the preparation method thereof, the contents of Ni and N in the precipitation-hardened martensite stainless steel are optimized, and the content of reverted austenite is controlled through the heat treatment process, so that the best matching between the strength and tenacity of the precipitation-hardened martensite stainless steel is obtained.

Description

technical field [0001] The invention relates to a precipitation hardening martensitic stainless steel and a preparation method thereof, belonging to the technical field of materials. Background technique [0002] The stainless steel roller screw is an important part of the nuclear power plant. The basic requirements for the material of the valve rolling screw in the nuclear power system include: 1) The surface has a high hardness, which meets certain wear resistance and surface contact strength; 2) The material It has a certain plasticity and toughness to avoid brittle fracture under impact loads such as switching valves; 3) it has better corrosion resistance under the environmental conditions of transportation, storage and installation, especially in the operating medium. In summary, the roller screw requires high hardness, high strength and toughness, and excellent corrosion resistance in different environments, especially a k The impact toughness requirement is not less ...

AI Technical Summary

Problems solved by technology

Due to reticular and banded Cr 23 C 6 The precipitation of carbides reduces the solid solution Cr content in the material matrix, thereby reducing its corrosion resistance

It is also worth emphasizing that the impact toughness of 90Cr18 high-carbon high-chromium steel is low, and it is less than 10J / cm2 after heat treatment. 2 , far lower than the performance index requirements of the roller screw, the sensitivity of the gap is relatively large, and it is easy to twist and break during use

Therefore, although 90Cr18 high-carbon high-chromium steel has relatively high hardness, it is not suitable as a material for nuclear power roller screw; PH15-7Mo is a martensitic precipitation hardening stainless steel, although the impact toughness after heat treatment meets the product requirements, but due to its The low hardness leads to poor wear resistance and cannot meet the requirements of the roller screw

[0004] Foreign countries have blocked my country for a long time on the composition design and preparation technology of roller screw materials, and because the demand for such materials is relatively small, and the comprehensive performance requirements of raw materials are relatively special, domestic research and development of related new materials has been In a state of neglect, especially the development and research of high-quality roller screw materials is limited

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