Rolling process of improving 38CrMoAl steel rolling state structure

Abstract

The invention discloses a rolling process of improving a 38CrMoAl steel rolling state structure. The rolling process is characterized by comprising the following steps of 38CrMoAl steel blank selection, steel blank heating, steel blank rough rolling, steel blank medium rolling, steel blank finish rolling and steel cooling. The rolling process of improving the 38CrMoAl steel rolling state structurehas the following advantages that a relatively low final rolling temperature is controlled, so that the surface temperature of a rolled piece is lower than a temperature of a core portion in the process, the steel core portion obtains a relatively large compressive stress in the rolling process, the structure uniformity is greatly improved, and crystal grains are further refined; the final rolling temperature is lowered to be close to the actual critical phase change point Ar3, a phase change from gamma to alpha is promoted, and a nucleation site of ferrite is increased, so that a structure morphology of a product is ferrite and pearlite structures in a balanced state; and the rolling process is green and environmentally friendly, does not pollute the environment, is capable of lowering the cost and increasing the benefit and particularly has important significance of controlling the online structure and the performance of medium-low carbon alloy structural steel.

Description

technical field [0001] The invention belongs to the technical field of iron and steel, and relates to a steel rolling process technology, in particular to a rolling process for improving the rolling microstructure of 38CrMoAl steel. Background technique [0002] 38CrMoAl steel has high nitriding performance and mechanical properties, good heat resistance and corrosion resistance, after nitriding treatment, it can get high surface hardness, high fatigue strength and good overheating resistance, no tempering brittleness. Used to manufacture small-sized nitriding parts with high fatigue strength, high wear resistance, precise size after heat treatment, and high strength, such as cylinder liners, seat covers, bottom covers, piston bolts, and inspection precision grinding machine spindles. The hot-rolled structure in production is mostly ferrite + pearlite + bainite + martensite, which is not conducive to subsequent processing and use by users. [0003] The production method in...

AI Technical Summary

Problems solved by technology

[0004] The existing technology does not adopt the controlled rolling process in the production process. Due to the characteristics of the steel type and the fast cooling rate after rolling, the non-equilibrium structure of the 38CrMoAl steel occurs, and the Brinell hardness of the rolled state reaches 300HB.

In order to meet the requirements of users, an annealing process must be added in the preparation of 38CrMoAl steel in the existing technology to solve the problems of abnormal structure and high hardness, the steps are cumbersome and the effect is not good

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