Effect of nickel equivalent on hydrogen gas embrittlement of austenitic stainless steels based on type 316 at low temperatures

• Published in: Acta materialia 2008-08, Vol.56 (14), p.3414-3421
• Main Authors: Zhang, Lin, Wen, Mao, Imade, Masaaki, Fukuyama, Seiji, Yokogawa, Kiyoshi
• Format: Article
• Language: English
• Subjects: Alloys; Applied sciences; Austenitic stainless steels; Embrittlement; Equivalence; Exact sciences and technology; Fracture mechanics; Fractures; Hydrogen embrittlement; Low-temperature deformation; Martensite; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Nickel; Stainless steel; Tension test
• ISSN: 1359-6454; 1873-2453
• DOI: 10.1016/j.actamat.2008.03.022

The effect of nickel equivalent on hydrogen gas embrittlement (HGE) of austenitic stainless steels of Fe–(10–20)Ni–17Cr–2Mo alloys vacuum-melted in a laboratory, based on type 316 stainless steel, was investigated. Tensile tests were conducted in hydrogen and helium at 1 MPa in the temperature range from 80 to 300 K. It was found that HGE of the alloys below a nickel equivalent of 27% increased with decreasing temperature, reached a maximum at 200 K, and then decreased with further decreasing temperature, whereas no HGE occurred above the nickel equivalent of 27%. It was observed that the content of strain-induced α′ martensite increased with decreasing temperature and nickel equivalent, and hydrogen-induced fracture occurred mainly along α′ martensite structure. Thus, the susceptibility to HGE depended on nickel equivalent. It was discussed that HGE was controlled by strain-induced α′ martensite above 200 K, whereas it was controlled by hydrogen transport below 200 K.