EFFECT OF STRAIN-HARDENING ON STRESS CORROSION CRACKING OF AISI 304L STAINLESS STEEL IN PWR PRIMARY ENVIRONMENT AT 360 deg C

摘要

Austenitic stainless steels (ASS) are widespread in primary and auxiliary circuits of PWR plants because of their good resistance to general corrosion at elevated temperature. Nevertheless, some components suffer stress corrosion cracking (SCC) under neutron irradiation. In order to avoid complex and costly corrosion facilities, the increase of hardness induced by irradiation on the material is commonly simulated by applying a strain hardening on non-irradiated material prior to stress cracking tests. Stress corrosion tests were conducted corrosionon AISI 304L ASS in a PWR environment (360 deg C). Particular attention was directed towards pre-straining effects on crack growth rate (CGR) and crack growth path (CGP). Results and electronic microscope examinations (SEM & TEM) have demonstrated that the susceptibility of 304L to SCC in high-temperature hydrogenated water was enhanced by pre-straining. It seemed that IGSCC was enhanced by strain localization.