Environmentally Assisted Cracking Behavior of Dissimilar Metal Weldments under High Temperature Water Conditions

Abstract

The environmentally assisted cracking behavior of Inconel Alloy 52-A508 weldment under simulated BWR coolant conditions was studied. Fatigue and corrosion fatigue crack growth rates of the dissimilar metal weldments were observed to increase with crack extension under the nominally constant ÁK loading mode. It can be accounted for by an increase in the tensile residual stress and a decrease in the crack closure effect with the weld depth. The tensile residual stress measured by hole-drilling strain gauges increased with the weld depth. After PWHT at 621 C for 24 h, the fatigue crack growth rate in the weld did not show to increase with crack length advancement. The crack closure effects in the weld were verified to decrease with the crack increment measured by the strain gauges in front of the crack tip.