The Role of Lattice Curvature on the SCC Susceptibility of Alloy 600

This study investigates the link between microstructure and stress corrosion cracking susceptibility for three heats of alloy 600 representative of plant components (forged control rod drive mechanism nozzle, rolled divider plate, and rolled divider plate stub). The experimental approach was designed to determine the effect of the manufacturing process (forged versus rolled materials) and the pre-strain (as-received versus pre-strained materials) on stress corrosion cracking of alloy 600. Results showed the carbide distribution to be the main microstructural parameter influencing SCC but a lattice curvature parameter, in synergy with the carbide distribution, has proven to give a better representation of the materials SCC susceptibilities.