I am still not understanding why this would be in the specs for mild steel materials, such as 414G, for example, if a customer could/would simply just specify a copper-bearing steel (Monel or other) if necessary for their job. I guess I could just assume that they would want the benefit of both materials combined. If that is correct, I have my answer. Like JStephen, I have never actually seen it specified. Thanks for the replies.