Effect of the Surface Grinding on the Environmentally Assisted Crack Initiation of 316 L Steel in Simulated Pressurized Water Reactor Water

Abstract

This paper presents results on the effect of a surface treatment on the environmentally assisted corrosion cracking in a pressurized water reactor chemistry. Slow strain rate testing of 316 L austenitic steel with selected rates was performed at pressurized water reactor (PWR) simulated water at 350 °C and in air at 300 °C. Detailed prior and post-testing characterization of two types of surfaces including roughness, hardness, and microstructural analysis was made. Transgranular cleavage-like environmentally assisted cracking (EAC) initiation and growth were observed under PWR conditions. The effect of two surface finishes on the cracking initiation was observed: (i) first crack initiates from the polished surface in a vicinity of the necking area rather than from the ground surface and (ii) then the deeper crack develops in the minimal diameter from the polished surface side than from the ground one.