Effects of Mo Addition on Intergranular Cracking Behavior of 2.25CrW (P23) Weld Metal at Elevated Temperatures

Abstract

A P23 weld metal showed a severe intergranular cracking at elevated temperatures. This reaction results from the strong segregation of impurities at the grain boundary carbide interfaces and the decrease in the bulk content of W which arises from the partitioning of W into carbides. Meanwhile, the other P23Mo weld metal containing 0.5 wt.% Mo showed a considerable ductility under the same conditions. The primary reasons for this result are the intrinsic grain boundary strengthening effect of Mo and the suppression of both the Fe(2)W Laves phase formation and the partitioning of W into carbides.