High Temperature Mechanical behaviour of Ni-Cr-Fe heat resistant cast steel

摘要

The effect of microstructure on the high temperature behaviour of a Ni-Cr-Fe heat resistant cast steel is investigated. Specimens issued from the columnar and equiaxe zones of the ingot are tensile tested up to 950°C. The comparative analysis of stress-strain and relaxation curves shows little difference in the macroscopic behaviour. Whatever the microstructure, the brittle to ductile transition occurs between 500°C and 750°C, and micro-cracking of interdendritic carbides is responsible of the instabilities shown on the stress-strain plots at 500°C.