Corrosion and SCC Properties of Fine Grain Stainless Steel in Subcritical and Supercritical Pure Water

Abstract

Abstract Fine grain austenitic stainless steels developed by means of cold work and a heat treatment process to improve the material properties for use in supercritical water-cooled power reactor (SCWR). The corrosion and Stress Corrosion Cracking (SCC) properties, were subsequently evaluated and described in the present paper. Results of corrosion test indicated that the corrosion rates of fine grain 304L SS and fine grain 310S SS were as low as 1/30~1/70 of those of the normal grain size Type 304L SS and Type 310S SS at 550°C. It was found that the grain refinement improved corrosion resistance significantly in SCW. The corrosion of austenitic stainless steel in super critical water consisted of both oxidization film growth and release into water. Results of slow strain rate test (SSRT) showed that the inter granular (IG) SCC susceptibility of fine grain material is low at 550°C and 290°C. From these results, fine grain materials are considered to be promising candidates for application as SCWR core components.