The effect of temperature of cryogenic treatment on microstructure and wear behavior of 1.2304 cold work steel

In this study، the effect of temperature of cryogenic treatment on hardness، microstructure، wear resistance and percentage of retained austenite of 1/2304 steel were investigated. For this purpose، two different cryogenic temperatures were used: -80 ºC as the shallow cryogenic temperature and -196 ºC as the deep cryogenic temperature. The results revealed that cryogenic treatment، caused an increase in hardness and a decrease in the percentage of the retained austenite compared to the conventionally treated specimen. Shallow cryogenic (SCT) and deep cryogenic (DCT) treatments increased the wear resistance of 5 -12 % and 37-52 %، respectively. Moreover، the wear debris and worn surfaces showed that the dominant mechanism in the wear test was adhesive. In the case of deep cryogenic treated specimen، the number of carbides increased while the carbides size was decreased. It was considered that the deep cryogenic treatment increased the driving force for the nucleation of carbides. The martensitic transformation start and finish temperatures were also studied using dilatometry tests. The results showed that the start and finish temperatures of the martensitic transformation were 254°C and - 87°C، respectively.