Morphology of stress corrosion cracking due to exposure to high-temperature water containing hydrogen peroxide in stainless steel specimens with different crevice lengths

Abstract Crack growth tests were performed in high-temperature water containing hydrogen peroxide (H 2 O 2 ) to evaluate the relationships between the crevice structure and H 2 O 2 on stress corrosion cracking (SCC) growth morphology of stainless steel (SS). Small compact tension (CT) specimens were prepared from thermally sensitized type 304 SS. 20–300 ppb H 2 O 2 was injected into the high-temperature water at 561 K. Intergranular SCC (IGSCC) and transgranular SCC were observed near the side grooves and the central region of the original CT specimens, respectively. Chevron notches were removed from the CT specimens after fatigue pre-crack introduction. Owing to pre-crack shortening, the IGSCC area expanded to the central region of the CT specimens and increased with H 2 O 2 concentration. The effects of H 2 O 2 on SCC appeared intensely near the surfaces exposed to high levels of H 2 O 2 . Microanalysis and distribution examination of oxide layers were performed and the percentage of H 2 O 2 remaining in the crack was calculated.