Stress corrosion cracking susceptibility of 310S stainless steel in hydrogenated hot water

The stress corrosion cracking (SCC) susceptibility of solution-annealed 310S stainless steel (SS) was examined by means of slow-strain rate test (SSRT) method in hot water (288 °C) with dissolved-hydrogen (DH), and the results were compared with those of 316L SS. Almost no SCC was observed in 310S SS, while a remarkable SCC was found in 316L SS showing brittle fracture surfaces and cracks on specimen side surfaces. The SCC observed in 316L SS started as IGSCC while necking, and transferred to TGSCC. It was also shown that sensitization resulted in the suppression of IGSCC of 316L SS. On the assumption that the SCC in hydrogenated hot water can be interpreted in terms of hydrogen assisted SCC, the mechanism of the suppression of SCC in 310S SS is related with a higher nickel content which increases stacking fault energy and facilitates cross slip of dislocations, resulting in the reduction of hydrogen concentration on a unit area of slip plane. Keywords: SSRT, Hydrogen assisted SCC, Cross slip, Stacking fault energ