The Truth Behind Mechanical Polished Surfaces

It has been an unwritten rule for years that the best passive and corrosion resistant stainless steel surfaces will have a Cr/Fe ratio in excess of 1.5/1 which in many cases is easily achievable. It is also well known and standard practice in the Pharmaceutical Industry, the acceptable roughness average of material in production vessels and water systems is a 15-25Ra value, many times achieved through a mechanical polishing procedures. It is this procedure that in this writer’s opinion causes many of the problems experienced today with the formation of the “gray residue” and Class 1 rouge that has plagued end users for years.