- References
{{refimprove|date=September 2018}}Rouging is a form of corrosion found in stainless steel. It can be due to iron contamination of the stainless steel surface due to welding of non-stainless steel for support columns, or other temporary means, which when welded off leaves a low chromium area.[1]There are three classes of rouging: Class I, Class II, and Class III. Class I - stainless steel surface and the Cr/Fe ratio{{clarify|this term needs to be defined|date=September 2018}} of the metal surface beneath such deposits usually remain unaltered. Class II - Iron particles originating in-situ on unpassivated or improperly passivated stainless steel surfaces. By their formation the Cr/Fe ratio of the metal surface is altered.
Class III - Iron oxide (or scale) which forms on surfaces in high temperature steam systems. The Cr/Fe ratio of the protective film is usually altered.
References1. ^{{cite web|url=http://corrosion-doctors.org/MatSelect/rouging.htm|title=Rouging|website=corrosion-doctors.org}}
{{Mech-engineering-stub}} 1 : Corrosion |