A method of increasing intergranular stress corrosion cracking resistance of Alloy 718 in water reactor environments is disclosed. The Alloy is heat treated at a high annealing temperature to dissolve .delta. precipitates. The absence of .delta. particles at the grain boundaries increases the elemental homogeneity at the boundaries and increases intergranular stress corrosion cracking resistance. In addition, the absence of .delta. phase at the grain boundaries decreases the crack propagation rate.