Delmet stainless steel excellence since 1949
DEROUGING
Rouging is a form of corrosion of stainless steel. The stainless steel derouging treatment ensures the correct removal of the rouge on the metal surfaces through the application of specific products with neutral pH.
THE PROBLEM
Rouge: what does it look like?
IN WFI SYSTEMS
Within WFI systems, especially in the pharmaceutical industry, rouge is visible as layers of reddish coating.
IN STEAM CIRCUITS
In the steam circuits rouge stratification is caused by a rather dark iron oxide coating which is concentrated mainly inside the fittings and in other areas of the circuit.
IN WATER CIRCUITS
In water circuits, a red or red-brown coating generally develops and settles or deposits on the inside of the pipes.
THE FACTORS
Rouge: what causes it?
Rouging is caused by various factors such as a low percentage of oxygen combined with high temperatures..
The higher the temperature in the system, the more the iron oxides multiply. The protective film is in a dynamic chemical equilibrium which can be altered if high temperatures induce an increase in the formation of iron oxides by sacrificing chromium oxide.
The risk of rouging increases if there has been inadequate passivation, incorrect welding with low quality material, the presence of oxides or other treatments performed on the surface.
DO YOU NEED OUR SERVICES?
Delmet is able to solve any query and problem related to the surface treatment of stainless steel.It offers contract processing, design and manufacture of customised plants, formulation and sale of chemicals and machines for the purification of process water and air treatment.
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