Effects of Cryogenic Treatment on the Hardness and Wear Resistance of Cr13Mn3MoV2 High Chromium Cast Iron

Effects of cryogenic treatment on the microstructure,hardness and wear resistance of the Cr13Mn3MoV2 high Cr cast iron(HCCI) have been investigated.The results show that the microstructure of high chromium cast iron constitutes of austenite,martensite and(Cr,Fe)7C3 eutectic carbide.After cryogenic treatment,the hardness of high chromium cast iron obviously higher than air cooling.Compared as-cast,with the temperature of sub-critical treatment increases from 400 ℃ to 650 ℃,the hardness experienced from below as-cast and increase to more than as-cast and the emergence of secondary hardening and then lower to the as-cast again at last.The main reason maybe is the recovery heat of martensite and the austenite transformed into martensite in the process of heat treatment.The wear resistance at 520 ℃ and 600 ℃ is the best,while at 540 ℃ it is lowest.Moreover,the wear resistance was not completely related to the hardness.