Don’t Be Passive About Passivation

A typical food contact surface finish for stainless steel is the so-called No. 4 Dairy or 32 Ra finish.  Although stainless steel is considered to be a non-reactive and non-rusting surface, regardless of the surface finish specified, rust or rouging can form under certain circumstances: if this metal alloy is contaminated with free iron, if it is damaged by heat treatments (including welding) or if it is put into service without proper passivation. In the May issue of Hixson’s From Experience newsletter, we look at two common methods used for the passivation of steel, and offer our insights (based on experience) into both.