Method for manufacturing bearing steel having excellent fatigue life at high temperature and contaminated environment

摘要

The present invention relates to a carbonitriding method that is used in high-temperature bearing steel producing automobile engine, etc.. ; in the production method by weight%, C: 0.30 ~ 0.50%, Si: 1.20 ~ 2.00%, Mn: 1.50 ~ 2.50%, Cr: 1.1 ~ 1.30%, V: 0.30 ~ 0.50%, Al: 0.030 ~ 0.050%, N: 0.020 ~ 0.030%, by carburizing the steel material to be in the composition balance of Fe and other unavoidable impurities, and so that the surface carbon concentration of 0.9 to 1.2% by weight, of the surface at 870 ~ 910 chimjil that the sum of the concentrations of carbon and nitrogen so that 1.2 to 1.7 wt%, then quenching and, at 830 ~ 860 2 comprises that the quenching car. ; This method is to increase the retained austenite amount, without reduction in the surface hardness by a carburizing and nitriding, and a two-stage quenching the alloy to form a carbide reinforced and stabilized by refining the element organization, foreign body in a high temperature environment there is an effect that can greatly improve bearing life compared to conventional carburizing bearing. In addition, the heat resistance of the bearing to the effect of the nitrogen diffusion in the alloy increases and the surface layer of the silicon content may also be increased.