Effect of hydrogen-gas pressure on threshold of hydrogen-induced crack growth for carbon steel JIS-SM490B, low-alloy steel JIS-SCM435 and stainless steel JIS-SUS304

Abstract

In order to clarify the effect of hydrogen-gas pressure on threshold of hydrogen-induced crack growth (K_I,H), elasto-plastic fracture toughness tests were performed on JIS-SM490B carbon steel, JIS-SCM435 low-alloy steel and JIS-SUS304 stainless steel. For JIS-SM490B and JIS-SUS304, the values of K_I,H at displacement rates of 2×10^–5 and 2×10^–4 mm/s were almost the same in hydrogen at pressures of p_H2= 20, 45 and 115 MPa (K_I,H ≒ 80 MPa·m^1/2 for JIS-SM490B and 150 MPa·m^1/2 for JIS-SUS304). In contrast, for JIS-SCM435, the values of K_I,H at displacement rates of 2×10^–5 and 2×10^–4 mm/s were the same in hydrogen gas at pressures of p_H2 = 20, 45 and 80 MPa (K_I,H ≒ 100 MPa·m^1/2); however, those of K_I,H were degraded in 115-MPa hydrogen gas (K_I,H ≒ 50 MPa·m^1/2). Based on the HISCG (Hydrogen Induced Successive Crack Growth) model, an effect of p_H2 on K_I,H and an existence of K_I,H were also discussed for JIS-SM490B, JIS-SCM435 and JIS-SUS304.