Preparation method of hydrogen-infiltration-resistant surface in situ nanocrystallized bainitic steel

Abstract

The invention discloses a preparation method of hydrogen-infiltration-resistant surface in situ nanocrystallized bainitic steel, and belongs to the technical field of high-strength alloy steel. The preparation method comprises the following steps of (1), heating matrix steel to 900 DEG C to 950 DEG C to perform complete austenitizing, and performing heat preservation for 20min to 40min; (2), quickly immersing the matrix steel subjected to heating and heat preservation treatment in a salt bath at a temperature of 260 DEG C to 350 DEG C, performing the heat preservation for 1.5h to 3h, and thenperforming air cooling; and (3), under certain contact stress, rolling the air-cooled matrix steel for certain cycles in a contact manner by a rolling contact device with a slip ratio, so that a nanocrystalline layer is subsequently generated on the surface of the air-cooled matrix steel, to obtain the hydrogen-infiltration-resistant surface in situ nanocrystallized bainitic steel. A matrix material is bainitic steel with a carbon content of 0.30% to 0.40%, and contains second-phase particles of dozens of nanometers to hundreds of nanometers. The nanocrystalline layer in the bainitic steel obtained by using the preparation method plays a role in impeding hydrogen infiltration, and can be used for effectively decreasing hydrogen embrittlement sensitivity and improving delayed fracture resisting performance.

Description

technical field [0001] The invention relates to the technical field of high-strength alloy steel, in particular to a surface in-situ nano [0002] The preparation method of the bainitic steel is used for rolling contact basic parts such as bearings with high requirements on surface fatigue wear performance, and can also be used for other important structural materials with high performance requirements for hydrogen embrittlement and delayed fracture characteristics. Background technique [0003] Nanomaterials have excellent mechanical and chemical properties, and extensive research has been done on nanomaterials at home and abroad. In some structural parts, the performance of the surface plays a key role. At present, a variety of surface nano-processing methods have been realized in the laboratory, and some have been applied to practical engineering. With the increasing research on surface nanotechnology, many domestic methods have been reported on the surface nanotechnolog...

AI Technical Summary

Problems solved by technology

[0005] The technical problem to be solved in the present invention is to provide a method for preparing a surface in-situ nano-sized bainitic steel resistant to hydrogen infiltration, using the latest optimization mechanism without the need for a heat source and without instantaneous severe plastic deformation. The matrix produces a core formed by a large number of nanocrystals, thereby preparing a unique surface nanocrystal layer, which can effectively prevent the infiltration of external hydrogen, thereby obtaining ultra-low hydrogen embrittlement susceptibility and extremely high delayed fracture resistance

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