On the exceptional stress corrosion cracking susceptibility of selective laser melted 316L stainless steel under the individual effect of surface residual stresses

SCC and electrochemical behaviour of selective laser melted 316L stainless steel was studied under the combined effect of surface residual stresses (RS) and energy input variation. A significant correlation was found between columnar subgrains width and pore size with the electrochemical response and SCC susceptibility. There existed a critical pore size affecting local corrosion behaviour which decreased with an increase in RS magnitude. The critical RS needed for SCC occurrence was lower compared to wrought counterpart and the SCC mechanism was hypothesized as the synergistic effect of exceptional selective corrosion attack at subgrains and mechanical rupture of subgrain boundaries.