HIGH TEMPERATURE MECHANICAL PERFORMANCE OF TYPE 316L STEELS MANUFACTURED BY POWDER METALLURGY HOT ISOSTATIC PRESSING

Abstract

Powder metallurgy / hot isostatic pressing (PM/HIP) is a manufacturing process that has the potential for use in the nuclear industry for the manufacture of components in future nuclear plants. The PM/HIP process possesses a variety of manufacturing, metallurgical and mechanical performance benefits, when compared to their wrought counterparts fabricated via more traditional and established techniques such as arc welding, casting and forging. In concert, these benefits may provide a reduction in manufacturing time and costs for new nuclear builds.

To investigate the potential benefits of PM/HIP-processed materials, this work examined the high temperature mechanical performance of two PM/HIP-processed Type 316L austenitic stainless steels. These materials possessed similar microstructures, but contained slight differences in chemical compositions related to their N and C contents. The tensile, low cycle fatigue and creep performance of these materials were determined at 600 °C. The mechanical properties were compared with wrought Type 316 stainless steels where possible. Microstructural analyses were undertaken to evaluate the deformation and failure characteristics.

The results obtained here revealed that the steel with higher N and Mn content possessed a clear mechanical performance enhancement, when compared with the lower N and Mn content material. The findings suggest that PM/HIP and its near-net shape capability, may offer some significant mechanical performance advantages over competing processes, like casting.