Corrosion of Ni-Cr-Mo Weldments on UNS N08367

There is currently interest in the use of a 6 Mo stainless steel (UNS N08367) for an application on naval vessels.  While the base material has good resistance to corrosion in marine environments, the welds are in a non-optimal metallurgical condition.  Therefore over-matched filler metals need to be used when welding this 6-Mo stainless steel in order to assure proper corrosion resistance.  The importance of weld dilution by the base metal is demonstrated.  The use of two Ni-Cr-Mo alloy (UNS N06022 and N06059) were used to produce welds of various dilution amounts and tested in high chloride environments to evaluate how pitting might be affected by changing filler metal and the amount of dilution from the base metal.