title: Hydrogen embrittlement property of a 1700-MPa-class ultrahigh-strength tempered martensitic steel.
abstract: The hydrogen embrittlement property of a prototype 1700-MPa-class ultrahigh-strength steel (NIMS17) containing hydrogen traps was evaluated using a slow strain rate test (SSRT) after cathodic hydrogen precharging, cyclic corrosion test (CCT) and atmospheric exposure. The hydrogen content in a fractured specimen was measured after SSRT by thermal desorption spectroscopy (TDS). The relationship between fracture stress and hydrogen content for the hydrogen-precharged specimens showed that the fracture stress of NIMS17 steel was higher, at a given hydrogen content, than that of conventional AISI 4135 steels with tensile strengths of 1300 and 1500 MPa. This suggests better resistance of NIMS17 steel to hydrogen embrittlement. However, hydrogen uptake to NIMS17 steel under CCT and atmospheric exposure decreased the fracture stress. This is because of the stronger hydrogen uptake to the steel containing hydrogen traps than to the AISI 4135 steels. Although NIMS17 steel has a higher strength level than AISI 4135 steel with a tensile strength of 1500 MPa, the decrease in fracture stress is similar between these steels.
authors.affiliation: School of Materials Science and Engineering, University of Science and Technology Beijing, No. 30 Xueyuan Road, Hidian Zone, Beijing 100083, People's Republic of China; Structural Metals Center, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan; Nippon Steel and Sumikin Metal Products Co, Ltd, SA Bldg., 17-12 Kiba 2-chome, Koto-ku, Tokyo, Japan; On leave from the University of Science and Technology Beijing, as a NIMS Junior Researcher.
authors.forename: Songjie
authors.initials: S
authors.lastname: Li
authors.affiliation: Structural Metals Center, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan.
authors.forename: Eiji
authors.initials: E
authors.lastname: Akiyama
authors.affiliation: Structural Metals Center, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan.
authors.forename: Kimura
authors.initials: K
authors.lastname: Yuuji
authors.affiliation: Structural Metals Center, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan.
authors.forename: Kaneaki
authors.initials: K
authors.lastname: Tsuzaki
authors.affiliation: Nippon Steel and Sumikin Metal Products Co, Ltd, SA Bldg., 17-12 Kiba 2-chome, Koto-ku, Tokyo, Japan.
authors.forename: Nobuyoshi
authors.initials: N
authors.lastname: Uno
authors.affiliation: School of Materials Science and Engineering, University of Science and Technology Beijing, No. 30 Xueyuan Road, Hidian Zone, Beijing 100083, People's Republic of China.
authors.forename: Boping
authors.initials: B
authors.lastname: Zhang
keywords: atmospheric corrosion; delayed fracture; high-strength steel; hydrogen embrittlement; slow strain rate test; thermal desorption spectroscopy