1 School of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, Jiangsu, China 2 Institute for Special Steel Institute, Central Iron and Steel Research Institute, Beijing 100081, China
Investigation of stress corrosion cracking behavior and mechanism analysis of a 1900 MPa-grade ultra-high-strength stainless steel
1 School of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, Jiangsu, China 2 Institute for Special Steel Institute, Central Iron and Steel Research Institute, Beijing 100081, China
摘要 The stress corrosion cracking (SCC) behavior of a 1900 MPa-grade ultra-high-strength stainless steel in 3.5 wt.% NaCl solution was investigated by X-ray diffractometer, scanning electron microscopy, electron back-scattered diffraction, X-ray photoelectron spectroscopy, and potentiodynamic polarization curves. The results showed that USS122G steel has good SCC resistance, and the critical stress intensity factor (KISCC) of USS122G steel was about 68.906 MPa m1/2 and KISCC/ KIC = 0.76 (KIC is plane strain fracture toughness). The existence of film-like austenite along the lath martensite boundary and the protective effect of thecc passivation film were the main factors for its high KISCC. Among them, the main components of the passivation film on the surface of USS122G steel were Cr2O3, Cr(OH)3, FeOOH, and Ni(OH)2. The fracture morphology of SCC zone was intergranular and transgranular. Through the slow and fast scanning rate polarization curve test results, it can be concluded that SCC mechanism of USS122G steel in 3.5 wt.% NaCl solution at the open-circuit potential was a mixed mechanism involving hydrogen embrittlement and anodic dissolution.
Abstract：The stress corrosion cracking (SCC) behavior of a 1900 MPa-grade ultra-high-strength stainless steel in 3.5 wt.% NaCl solution was investigated by X-ray diffractometer, scanning electron microscopy, electron back-scattered diffraction, X-ray photoelectron spectroscopy, and potentiodynamic polarization curves. The results showed that USS122G steel has good SCC resistance, and the critical stress intensity factor (KISCC) of USS122G steel was about 68.906 MPa m1/2 and KISCC/ KIC = 0.76 (KIC is plane strain fracture toughness). The existence of film-like austenite along the lath martensite boundary and the protective effect of thecc passivation film were the main factors for its high KISCC. Among them, the main components of the passivation film on the surface of USS122G steel were Cr2O3, Cr(OH)3, FeOOH, and Ni(OH)2. The fracture morphology of SCC zone was intergranular and transgranular. Through the slow and fast scanning rate polarization curve test results, it can be concluded that SCC mechanism of USS122G steel in 3.5 wt.% NaCl solution at the open-circuit potential was a mixed mechanism involving hydrogen embrittlement and anodic dissolution.
Shuai Tian,Zhen-bao Liu,Ren-li Fu, et al. Investigation of stress corrosion cracking behavior and mechanism analysis of a 1900 MPa-grade ultra-high-strength stainless steel[J]. Journal of Iron and Steel Research International, 2022, 29(09): 1474-1484.
2022, Vol. 29 
