Effect of chemical composition on grain boundary microchemistry and stress corrosion cracking in Alloy 182

Effects of chemical composition on grain boundary microchemistry and stress corrosion cracking (SCC) in two kinds of modified Alloy 182 with different hot-cracking resistance were investigated. The results showed that while decreasing concentrations of C, P and S but increasing the concentration ratio of (Nb + Ta)/Si can enhance hot-cracking resistance of the alloy, SCC susceptibility in primary water was promoted simultaneously, which is most likely due to the lowered creep resistance by a lower precipitate density and less P segregation at the grain boundary in the alloy.

► Composition effect on grain boundary chemistry and SCC in two Alloys 182 was studied.
► Alloy 182–1 has higher concentrations of C, P, S and a lower ratio of (Nb + Ta)/Si.
► Segregation of P and Si and more precipitates at the grain boundary in Alloy 182–1.
► Alloy 182–1 showed a higher resistance to SCC in primary water than Alloy 182–2.
► P segregation and more tortuous grain boundaries caused higher SCC resistance.