TWI Industrial Member Report Summary 250/1984
By G E Hale
The pitting resistance of a series of experimental weld metals, with a base composition of 20%Cr-25%Ni-4.5%Mo-1.5%Cu, together with commercially available matching composition parent and weld metals has been examined. Weld pads were produced for both commercial and experimental MMA consumables and the pitting resistance of weld metal and parent plate was measured using a ferric chloride immersion test. For the range of weld metal compositions investigated, pitting resistance of the weld metal was always lower than that of the corresponding parent material. Increasing the chromium content of the matching composition weld metal from 20 to 25% did not enhance the pitting resistance. Niobium additions of up to 0.35% caused a small reduction in pitting resistance and an analogous effect was observed in weld metal containing 6% manganese and 0.4% nitrogen. This work has indicated that heat input, via its influence on solidification behaviour, may have an important effect on weld metal pitting resistance in high alloy austenitic materials.