Effect of impurities in dissimilar metal welds on their corrosion behavior

Abstract

Dissimilar metal welds are commonly used constructional solutions in most light-water reactors. Unfortunately, it may also be a source of operational problems due to the combination of two or more metals with different corrosion resistance. For welds of carbon and austenitic steel, it is possible to observe damage in the austenitic steel, which is the material with better corrosion resistance. This self-contradictory phenomenon is presumed to be caused by the segregation of impurities (S, P, C) from carbon steel on austenitic grain boundaries. The goal of this study is to demonstrate the effect of these impurities on the corrosion behavior of Fe-Cr-Ni alloys with different Cr and Ni content by using electrochemical methods.