Rouging is the red-orange discolouration that appears on the internal surfaces of process equipment from ultraclean networks, such as autoclaves, production and water for injection (WFI) distribution networks or clean steam networks.
It indicates a disturbance in the naturally present passivated layer on stainless steel metallic surfaces by the formation of iron oxides and other metallic oxides. This phenomenon leads to oxidisation in stainless steel, and this, in time, can lead to a dissemination of iron oxide in the network and therefore contaminating the pure fluids.
Case study of Cleaning and Passivation
Case study of De-rouging