1985 年 3 巻 3 号 p. 647-652
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, Smin, 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, KI. 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.