On the role of residual strain in controlling sensitisation of twin-boundary engineered type 304 stainless steel

Sensitisation in twin boundary engineered type 304 austenitic stainless steel (SS) was investigated using electrochemical potentiokinetic reactivation technique. As-received (AR) specimens of type 304 SS were given two solution-annealing treatments at 1000 °C for 0.5 and 2 h. Solution-annealed specimens were given a small strain of 5% using cold-rolling followed by strain–annealing (strain–annealing) at 927 °C for 24, 48, and 72 h. Electron backscatter diffraction analyses have shown increase in fraction of special boundaries (Σ⩽29) in two solution-annealed specimens. Twin-boundary engineered specimens were given two potential sensitisation treatments at 575 and 675 °C for 1 h. The increase in twin fraction and decrease in grain average misorientation (GAM) always resulted in reducing the extent of sensitisation. An exponential correlation between GAM and twin-fraction was established and increase in GAM always associated with increase in twin-fraction.