Influence of different cryogenic treatments on high-temperature wear behavior of M2 steel

Cryogenic treatment is an effective process to enhance the wear resistance of work pieces. Influences of cryogenic temperature, holding time and cooling rate on high-temperature wear behavior of M2 steel were studied, using a computerized ball-on-disc wear tester (HT1000). The results of the experimental tests showed that lowering the cryogenic temperature and prolonging the holding time, the wear resistance increased until being saturated. The optimal treatment condition was identified as cryogenic treatment = 77 K, holding time = 24 h, and the cooling rate = 2 K/min. However, there is no obvious difference in the friction coefficient among samples experienced different treatments. The specimen of M2 steel experienced traditional heat treatment more involved adhesive wear, where as that experienced cryogenic treatment showed more oxidative wear during high-temperature wear testing. Microstructure features of worn surface were analyzed for understanding underlying mechanisms. (C) 2016 Elsevier B.V. All rights reserved.