Microstructure and mechanical properties in HT9 and HT9M steels for nuclear power plant

摘要

Microstructure and mechanical properties of HT9and HT9M steels for liquid metal reactor(LMR) core materialshave been investigated. The tempering temperature at which cellstructure was formed by rearrangement of dislocations was samein two steels. More carbides were precipitated in HT9 steel due tohigh carbon content and precipitation of carbides was delayed inHT9M steel. Thus the decrease of hardness with temperingtemperature in HT9M steel was lower than that of HT9 steel. Theyield strength was decreased, the fine prior austenite grain wasformed, and the formation of #delta# ferrite was restricted inHT9M steel by decreasing the Cr and carbon content andincreasing the Nb content. Thus the impact property of HT9M steel was improved.