TWI Industrial Member Report Summary 316/1986
By P I Marshall
A recurrent problem in welded stainless steel fabrications is that joints made autogenously or with matching composition fillers may suffer preferential weld metal corrosion. In the present study, the influence of changes in weld metal composition has been examined with particular attention paid to the elements known to confer corrosion resistance to stainless steels, viz, Cr, Mo and nitrogen. The pitting corrosion resistance of four wrought materials and 20 manual metal arc (MMA) weld metals deposited from commercially available and experimental manual metal arc electrodes has been tested in chloride media. Most of these weld metals were fully austenitic although several contained some ferrite. The microsegregation of Cr, Mo and nitrogen was studied, and the chemical heterogeneity related to the morphology of corrosion attack.