Abstract:
The effect of cryogenic treatment on the microstructure, hardening behavior and wear resistance of subcritical treated GX200Cr13Ni6WMoMn was investigated. The specimens were improved for thermal shock resistance by having an austenitic matrix in place under all heat treatment conditions. After subcritical treatment, heat treatment increased the hardness and wear resistance of all the specimens since thin secondary carbides precipitated in the rich retained austenite. The amount of precipitated secondary carbides and martensite transformed by cryogenic treatment was greater than by air-cooling. The cryogenic process reduced the amount of austenite, but the austenite retained was not completely converted into secondary carbides. The abrasion resistance, toughness and hardness of the specimens were markedly improved by primary carbides and secondary carbides after heat treatment for 1 h at 900 degrees C.
