Any manufacturing or handling of stainless steel implies the potential risk of weakening the corrosion resistance. Should this weakening be larger than the built-in safety margin for the steel as compared to the corrosivity of the environment, one has to reestablish the original corrosion resistance of the steel. In most cases, the cheapest and safest way to do this is by performing a chemical surface treatment.
Bluish heat tinting around welds in a 4301 stainless steel tank.If kept untre-
ated, the risk of pitting corrosion in the bluish zone is signiﬁ - cant, and therefore,
the heat tinting must be removed. The easiest way to do this is a pickling.