Effects of phosphorus segregation on stress corrosion cracking in the heat-affected zone of a dissimilar weld joint between a Ni-base alloy and a low alloy steel

• Effect of P segregation on SCC in Alloy 182-A533B dissimilar weld was studied.
• Segregation of solutes was mainly induced by welding and step cooling.
• P segregation promoted crack growth/reactivation in heat-affected zone of A533B.
• Crack in heat-affected zone prefers grain boundary and cementite–matrix interface.

Effects of phosphorus segregation on stress corrosion cracking (SCC) in the heat-affected zone of an Alloy 182-A533B dissimilar weld joint in high-temperature, oxygenated water doped with SO42− and Cl− were evaluated by creviced bent beam test. Results indicate that step cooling and the addition of Cl− promoted SCC propagation and reactivation in the HAZ after cracks reach the fusion boundary. It is also suggested that phosphorus segregation at grain/packet boundaries and precipitate–matrix interfaces have promoted SCC, especially in coarse-grained HAZ and intercritically reheated coarse-grained HAZ.