SCC behaviours of austenitic stainless steel Z3CN20-09M in high temperature water

Stress corrosion cracking (SCC) behaviours of Z3CN20-09M stainless steel in high temperature water containing Cl− were studied. The results indicated that SCC sensitivity was inconsistent with test temperature. The minimum and maximum of SCC sensitivity occurred at 320 and 290°C respectively, and SCC sensitivity at 250°C fell between them. SCC crack initiated preferentially at bottom of corrosion pit or along phase boundary between austenite and ferrite, and its propagation depended on relative orientation to the phase boundary. SCC crack parallel to the phase boundary propagated along the phase boundary, while that perpendicular to the phase boundary was hindered to propagate.