Crack propagation resistance of Zeron 100 weld metal fabricated using the GTA and SMA welding processes

It is envisaged that super duplex stainless steels, as currently used in the offshore oil and gas industries, will find application in the emergent renewable energy sector in areas such as offshore wind, wave and tidal electricity/hydrogen generation. Such applications typically involve engineering components experiencing fluctuating loads. Sub-critical flaws inherent in welded joints are ideal sites for crack initiation and subsequent propagation leading to fast fracture. The current paper investigates the fatigue performance of two Zeron 100 weld metals in a benign environment (laboratory air). The effects of residual stresses and misalignment inherent from the welding process are also considered. The crack propagation threshold and the intrinsic crack propagation resistance of both weld metals was found to be similar to that of the base metal. However, the fracture toughness of the base metal was superior to the GTA weld metal, which was in turn better than the SMA weld metal.