Preventing and removing of heat tint

Abstract

Heat tinting is a thickening of the naturally occurring oxide layer on the surface of the stainless steel during welding. The thickness of the oxide layer next to the weld depends on the temperature, heating time, and oxygen concentration in the shielding gas. On stainless steels chromium is drawn from below the surface of the metal to form a chromium-rich oxide surface layer. During welding, the shielding gas should be used to prevent heat tint formation. If formed, heat tint must be removed in order that the full corrosion resistance of the finished product is restored after welding. Mechanical and/or chemical methods of removing heat tint that have been usually applied are described in this article.