Distribution of hardness,grain boundary chemistry,types of grain boundary and fraction,local deformation and stress corrosion cracking of Ni-base Alloys 600 and 690 heat-affected zones in simulated pressurized water reactor primary water are characterized and measured.With increasing the distance from the weld fusion line in Alloys 600 and 690 heat-affected zones,micro-hardness decreases,kernel average misorientation decreases and the fraction of coincide site lattice boundaries increases.Chromium depletion at grain boundaries in an Alloy 690 heat-affected zone is less significant than that in an Alloy 600 heat-affected zone.The intergranular stress corrosion crack growth rate in the Alloy 600 HAZ is close to that in the 8%CW base metal,which is significantly lower than that in the 20%CW base metal,but much higher than that in the as-received base metal.Alloy 690 heat-affected zone exhibits much higher IGSCC resistance than Alloy 600 heat-affected zone in simulated pressurized water reactor primary water.8 and 20%cold work Alloy 600 materials exhibit intergranular stress corrosion cracking while 40%worked Alloys 600 and 690 exhibit localized intergranular stress corrosion cracking.The effects of metallurgical and mechanical properties on stress corrosion cracking in Ni-base Alloys are discussed.