Cleaning/passivation stainless steels

Electro-polished surfaces

Electropolished surfaces already possess a passivated surface, although residuals from elctropolishing bath can’t be completely removed. If such surfaces are being used without additional processing e.g. welds or mechanical changes, then theoretically it would be possible to forgo an initial cleaning/passivation. Experience shows, however, that contamination which occurs whilst constructing a system or in some cases even some residuals from the electropolishing can lead to surface problems during operation! It is impossible to totally avoid typical constructional contamination such as fats, shavings, rust film or building material deposits. Even the fine surface layer formed during welding, which is practically invisible to the naked eye, is known to impair the passive layer and should be removed!
To sum up: Systems and components which have been cleaned and passivated from the beginning have proven themselves better in the application and have better surfaces. Repeated follow-up treatments are, however, important and maintain the functional characteristics of the stainless steel.