Investigation of stress corrosion cracking behavior and mechanism analysis of a 1900 MPa-grade ultra-high-strength stainless steel

• Published in: Journal of iron and steel research, international international, 2022-09, Vol.29 (9), p.1474-1484
• Main Authors: Tian, Shuai, Liu, Zhen-bao, Fu, Ren-li, Wang, Xiao-hui, Liang, Jian-xiong
• Format: Article
• Language: English
• Subjects: Applied and Technical Physics; Engineering; Machines; Manufacturing; Materials Engineering; Materials Science; Metallic Materials; Original Paper; Physical Chemistry; Processes
• ISSN: 1006-706X; 2210-3988
• DOI: 10.1007/s42243-021-00710-2

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 ( K ISCC ) of USS122G steel was about 68.906 MPa m 1/2 and K ISCC / K IC  = 0.76 ( K IC 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 K ISCC . Among them, the main components of the passivation film on the surface of USS122G steel were Cr 2 O 3 , 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.