Abstract
Anisotropy in stress corrosion cracking of lean grade UNS S32101 and standard grade UNS S32205 hot rolled duplex stainless steels was evaluated in this study. Microstructures were characterised with stereology methods in three orthogonal orientations to quantify anisotropy in phase distribution. Constant extension rate tests were conducted in an autoclave at 2×10−6 s−1 in chloride containing alkaline sulphide solution at 170°C. The maximum crack lengths and average crack densities were measured for the rolling longitudinal and transverse longitudinal orientations after stress corrosion cracking tests. Results indicate that stress corrosion crack initiation and growth are a strong function of the microstructure in each orientation. Maximum crack length and average crack density were maximum for the rolling longitudinal orientation. Crack initiation and growth were favoured along the transverse direction. Chlorides enhanced anisotropy in crack growth behaviour by facilitating crack initiation and crack coalescence along phase boundaries, which lead to more severe stress corrosion cracking in the alkaline sulphide environments that were studied.
Get full access to this article
View all access options for this article.