Q: We recently started doing work that requires some components to be manufactured from mostly 304-grade stainless steel, which is welded to itself and to mild steel. We’ve experienced some cracking issues on the stainless-to-stainless welded sections that are up to 1.25 inches thick. It was mentioned that our ferrite numbers are low. Can you explain what this is and how to correct the issue? A: That’s a great question. And yes, we can help you understand what it means to have low ferrite numbers and how to prevent it. First, let’s review what defines a stainless steel (SS) and then how ferrite relates to the welded joints. Ferrous steels and alloys contain more than 50 percent iron. This includes all carbon and stainless steels as well as other defined groups. Aluminum, copper, and titanium don’t contain iron, so they are great examples of nonferrous alloys. The primary constituent of the alloy is iron content of at least 90 percent for carbon steel and 70 to 80 percent for SS. To be classified as a SS, it must have a minimum of 11.5 percent chromium added to it. Chrome content higher than this minimum threshold promotes the formation of a chrome-oxide film on...