Fatigue crack growth (FCG) in Z2CND18-12N austenitic stainless steel and its heat-affected zone (HAZ) in the Z2CND18-12N/16MND5 dissimilar metal weld joint has been investigated in room temperature air and 325°C water. The dependence of FCG rates on specimen orientation in room temperature air got somewhat evident as ΔK decreased to 13 MPa√m. However, for Z2CND18-12N steel, the influence of specimen orientation on the FCG in room temperature air and the corrosion fatigue crack growth (CFCG) in 325°C water was slight and negligible. A moderate increase in the FCG rate was observed for the Z2CND18-12N HAZ in room temperature air at a low ΔK = 13 MPa√m (near ΔK threshold), compared with its base metal. However, the CFCG rate difference between the Z2CND18-12N HAZ and its base metal was minor. The CFCG in the Z2CND18-12N in 325°C water (without the addition of H2) was consistent with a slip-oxidation-rupture mechanism and the oxide film on the corrosion fatigue crack tip mainly consisted of Fe3O4.

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