A Study on Austenite Catalytic Cryogenic Treatment of Cr-W-Mo-V High Alloy Medium-Upper Carbon Steel

摘要

The processing of austenite catalytic cryogenic treatment of two components of Cr-W-Mo-V high alloy medium-upper carbon steels and the effect on the retained austenite transformation and tempering hardness were studied in this paper. The results show that, the effect of austenite catalytic cryogenic treatment of Cr-W-Mo-V high alloy medium-upper carbon steel is better than that of direct cryogenic treatment after quenching, and the content of residual austenite reduced to below 5%, and the hardness improved by 1.5HRC than that of conventional quenching and tempering. The retained austenite catalytic temperature of Cr-W-Mo-V high alloy medium-upper carbon steel merely is higher than 10°C~20oC of the temperature for the highest tempering hardness. Catalytic temperature Tc can be determined by experimental method of conventional quenching and tempering of the steel, in which the microstructure feature is precipitation of M_3C carbide particle of 0.01μm~0.03μm in martensite matrix, and the content of retained austenite decreases evidently. By cryogenic treatment after the austenite catalyzed the retained austenite of quenching are transformed into more martensite, and in the subsequent tempering processing the original quenching martensite and the martensite from retained austenite transformation almost will form synchronous precipitation hardening. Thus the tempering hardness improves evidently as well.