The Effect of Aging Conditions on the Microstructure and Mechanical Properties of HT9 Steel for Fuel Cladding Tube

摘要

The effect of aging heat treatment was investigated in a HT9 steel for the Sodium-cooled Fast Reactor (SFR) fuel cladding tube. Aging heat treatment was carried out at 660 degrees C for up to 7000 hours and then microstructural analysis and mechanical tests, namely tensile and vickers hardness tests, were performed. The results showed that size of the carbide and lath were increased after aging, while the size of the prior austenite grain was not changed. Both the strength and hardness were decreased with aging, and these tendencies were similarly represented after the 3000 hours of aging. Based on the experimental results, the tempering parameter was modified and discussed with aging conditions.