Enhancing the Wear Resistance of 100Cr6 Bearing Steel Using Cryogenic Treatment

The purpose of this study is to examine the effect of cryogenic treatment on the enhancement of the wear resistance of 100Cr6 bearing steel. The study also aims to reveal the underlying mechanisms responsible for the enhancement of wear resistance by deep cryogenic treatment (DCT) at -185 degrees C. The wear behavior was assessed by a reciprocatory friction and wear monitor under varying normal loads (ASTM International, Annual Book of Standards, 1996). It was found that the wear resistance was increased by 37% due to DCT when compared with that of conventional heat treatment (CHT). A scanning electronmicroscopy (SEM) study was also conducted to identify the possible mechanism that augments the improvement in the wear resistance of cryogenically treated 100Cr6 bearing steels. The microstructural study suggests that the improvement in the wear resistance is attributed to the conversion of the retained austenite into martensite, along with the precipitation and distribution of the carbides brought in by the cryogenic treatment. The differential scanning calorimeter (DSC) analysis conducted on the bearing steel samples showed that the DCT mainly enhances the destabilization of martensite by activating carbon clustering and transition carbide precipitation. Deep cryogenic treatment demonstrated more improvement in the wear resistance and hardness compared with conventional heat treatment.