The most common sign that there is a problem with a stainless steel weld is a change _____________

• A. Bead width
• B. Porosity in weld
• C. Bead color after the weld
• D. Spatter on the weld

Answer: (C)

Stainless steel welds are very sensitive to heat and oxidation, so the bead color after welding becomes a quick and telling visual cue of what happened during welding. When shielding gas coverage is inadequate or heat input is too high, chromium in the stainless oxidizes and forms a surface oxide layer. That oxidation shows up as a range of colors—straw, brown, purple, blue—that indicates oxidation and a loss of corrosion resistance. Because this discoloration is so directly linked to how the weld was made, it’s the most noticeable and common sign of a problem on stainless. Other issues like porosity, changes in bead width, or spatter can occur as well, but they aren’t as universally indicative of stainless-specific problems and can arise from a variety of causes.