Improvement and heat treatment process of stainless steel 1.4740 material

Abstract

The invention relates to the technical field of heat treatment, in particular to an improvement and heat treatment process of a stainless steel 1.4740 material. Chemical components of the 1.4740 material are optimized through the process, the residual stress is eliminated, a crushing condition generated when a shell is vibrated is reduced, the structure is uniform, the hardness is controllable, the machining is facilitated, the annealing efficiency is improved, and the cost is reduced; and the stainless steel 1.4740 material comprises the following element contents of, in percentage, 0.3%-0.4%of C, 1%-1.5% of Si, less than or equal to 0.5% of Mn, less than or equal to 0.04% of P, less than or equal to 0.03% of S, 16%-17% of Cr, less than or equal to 0.5% of Ni and less than or equal to 0.5% of Mo. According to the improvement and heat treatment process of the stainless steel 1.4740 material, the to-be-treated stainless steel is subjected to normalizing treatment, the temperature is 850 DEG C-900 DEG C, heat preservation is carried out for 4.5-5.5 hours, the carbon potential in a furnace is 0.18, and when air cooling is directly carried out to 200 DEG C in the furnace, the stainless steel is discharged out of the furnace.

Description

technical field [0001] The invention relates to the technical field of heat treatment, in particular to an improvement of stainless steel 1.4740 material and a heat treatment process. Background technique [0002] The material of stainless steel 1.4740 is relatively common in the market at present, and it has the following characteristics: [0003] High carbon: 0.3-0.5%; ensure the excellent mechanical properties of the material; [0004] High silicon: 1-2.5%, improve the high temperature performance of castings; [0005] High chromium: 16-19%, improve the corrosion resistance of the material; [0006] 1. The material structure of 4740 is a ferrite matrix, distributed in lath-like [Fe,Cr]C (a compound of iron, chromium and carbon), the material has high hardness (as-cast hardness: about 500HBW), low toughness; no phase change occurs during heat treatment , mainly to improve the distribution of carbides; at the same time, avoid the embrittlement temperature of 475°C to pre...

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Problems solved by technology

[0012] In order to solve the problems of poor strength of existing stainless steel 1.4740, the shock shell is prone to broken castings, difficult processing, long annealing cycle, low efficiency, high cost, uneven structure and uncontrollable hardness, the invention provides an improved material of stainless steel 1.4740 And heat treatment process, which optimizes the chemical composition of 1.4740 materials, eliminates residual stress, reduces the cracking of shells, has uniform structure, controllable hardness, facilitates machining, improves annealing efficiency and reduces costs

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