Heat treatment process of steel workpiece

Abstract

The invention discloses a heat treatment process of a steel workpiece. The heat treatment process comprises the following steps of S1, normalizing treatment: S11, normalizing; S12, air cooling, wherein the steel workpiece obtained after normalizing heat treatment is taken out of a furnace, and air cooling is conducted till the surface temperature of the steel workpiece is reduced to 600-650 DEG C;S13, heat preservation treatment, wherein the steel workpiece is returned to the furnace, and the temperature in the furnace rises; when the temperature in the furnace is higher than 700 DEG C, stepS12 is repeated; and when the final temperature in the furnace is 675-690 DEG C, step S14 is executed; and S14, cooling along with the furnace; S2, carburizing: S21, strong carburizing treatment, wherein the workpiece treated in step S1 is transferred into a carburizing furnace, the temperature is increased to 900-930 DEG C, and strong carburizing treatment is conducted for 4.5-5.5 h; S22, diffusion treatment, wherein after strong carburizing treatment is completed, the temperature of the carburizing furnace is kept unchanged, and diffusion treatment is started for 5.5-7 h after the carbon potential of the workpiece is reduced to the preset diffusion carbon potential; S23, temperature equalization treatment; and S24, high-temperature tempering; S3, quenching; and S4, low-temperature tempering. According to the heat treatment process of the steel workpiece, heat preservation treatment is conducted through waste heat of the steel workpiece after normalizing, and energy consumption is reduced by about one third; and the carburized layer peeling phenomenon is avoided, and the workpiece quality is good.

Description

technical field [0001] The invention relates to the technical field of heat treatment, in particular to a heat treatment process for steel workpieces. Background technique [0002] Heat treatment refers to a metal thermal processing process in which the chemical composition and structure of the surface or interior of the material are changed by means of heating, heat preservation and cooling in the solid state to obtain the required properties. [0003] In the heat treatment process, steel workpieces generally need to be processed by normalizing, carburizing, quenching and other processes, but most of the existing normalizing treatment processes first cool the workpiece to room temperature, and then heat up and temper, resulting in high energy consumption , the process cycle is long, and the operation is complicated; secondly, the intensive infiltration treatment time in the carburizing treatment process is generally longer than the diffusion treatment, resulting in the peel...

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Problems solved by technology

[0003] In the heat treatment process, steel workpieces generally need to be processed by normalizing, carburizing, quenching and other processes, but most of the existing normalizing treatment processes first cool the workpiece to room temperature, and then heat up and temper, resulting in high energy consumption , the process cycle is long, and the operation is complicated; secondly, the intensive infiltration treatment time in the carburizing treatment process is generally longer than the diffusion treatment, resulting in the peeling of the carburized layer of the current steel workpiece during use. Improvement, drilling and other special fields have high requirements on the quality and service life of steel workpieces. Therefore, it is urgent to improve the heat treatment process of existing steel workpieces in order to reduce energy consumption during heat treatment and effectively slow down the carbon concentration on the surface of steel workpieces. The distribution gradient, and then improve the quality of steel workpiece products, to meet the market demand for energy saving and consumption reduction

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