CONSIDERATION OF REDUCED NICKEL-CONTAINING AUSTENITIC STAINLESS-STEELS FOR FORMING APPLICATIONS

The ductility and deep drawability of three austenitic stainless steels containing low nickel levels (5.5 wt%) and copper additions (0, 1.3 and 3.3 wt% respectively) are reported. The formation of deformation-induced martensite leads to enhanced tensile ductility but results in the occurrence of delayed cracking after drawing when no copper is present. The corrosion rate of the alloys was investigated after ageing at 700-degrees-C in view of the possibility of making use of a post-forming stress relief heat treatment to prevent delayed cracking. A very high corrosion rate was recorded for the copper-free alloy following deformation and ageing which militates against post-forming remedial action.