The Suitability of C-276 Filler for Super Duplex Stainless Steel Welds in Seawater

Super duplex stainless steel has been used for seawater cooling and firewater systems, with butt welded piping since 1991. There have been a few failures, mostly due to overchlorination or operation at too high a temperature. There is an increasing desire to operate at higher seawater temperatures, and the present work was undertaken to determine if a nickel-based filler metal would offer a significant improvement. The results showed that the weld adopts potentials lower than that of the parent metal in chlorinated seawater, even when coupled. At these lower potentials, the nickel alloy filler tested showed a significantly higher resistance to pitting than the conventional super duplex consumable.