Preferential Weld Corrosion (PWC)

The Preferential Weld Corrosion (PWC) means when C-Mn steels are in an environment which causes active corrosion it is often found that weldments are more severely affected than parent material. This is known as preferential weld corrosion (PWC). It has notably been observed in sea water injection systems in North Sea oil and gas production systems, although this is by no means the only situation in which preferential corrosion is observed. The problem arises from the fact that weld metal compositions (which are normally optimised for mechanical properties) tend to be slightly anodic to the parent steel. Therefore, the weld metal corrodes at a higher rate than the parent. (Source: www.twi-global.com/)