Characteristics of Stress Corrosion Cracking in Stainless Steel under Mixed Mode Condition

Abstract

Stress corrosion crack initiation feature of Type 304 steel in 42%MgCl₂ aq. sol. under mixed mode stress condition was studied. Brittle fracture criteria, Kσ(θ)_max, S_min, G(γ)_max were tried to apply to SCC initiation. As the result, it was made clear that threshold stress field intensity for SCC in mixed mode condition was more adjusted by these criteria than only mode I stress intensity, K_I. In addition, Micro morphology of SCC fracture surface were studied by fractography. Fracture planes in SCC initiation point was mainly constituted by {100} plane and scarcely {111} slip plane which was observed only localized point. This shows that SCC was seemed to be more susceptible to opening mode than shear mode.