Bearing steel surface contact fatigue and the organization of crystallization and phase change of the research

Bearing steel surface contact fatigue and the organization of research 2019 - crystallization and phase transformation 08 - 20 Su Yunshuai shu-xin li, LuSiYuan ( Jiaxing university school of mechanical engineering and mechanics, jiaxing 315211). Major equipment of premature bearing failure, seriously affect the safe operation and reliability of the system. Unlike ordinary fatigue, contact materials under fatigue load organizational change will happen. However, about the contact fatigue under non crystallization and austenitic phase transformation in the material research has not been reported. Martensite bearing steel contact fatigue experiments, the author of this paper, study the surface material of white etching, the amorphous and organizational transformation are analyzed in detail, discuss its mechanism. （ 一) White etching area ( 我们) The amorphous phase, b） WEA austenitic phase transformation in the EBSD and TEM test results show that the contact fatigue loading, the original plate strip martensite structure occurred the following changes: amorphous and nanocrystalline and phase transformation ( Martensite to austenite transformation) 。 WEA is mainly composed of amorphous phase, in which the dispersion of nanometer martensite and austenite and carbide, as shown in figure ( 一) 。 The hardness is much higher than the matrix. At the interface between WEA and matrix, there are obvious transition zone 3 - 5 nm, crystal from order to disorder. Raw materials containing 3% retained austenite, but WEA austenite content increased to 20%, in the figure, b） 。 That in the process of fatigue deformation, produced from martensite to austenite transformation. Mechanism research show that the phase transition is not due to the austenitizing temperature occurs after the transformation, but under the condition of large mechanical deformation of crystal staggered in atom.