What about our stainless steel flagpoles passivating and pickling

Posted on 2013-11-26 | 90 views

Passivation

Passivation usually occurs naturally on the surfaces of stainless steels, but it may sometimes be necessary to assist the process with oxidising acid treatments. Unlike pickling, no metal is removed from the surface during acid assisted passivation. The quality and thickness of the passive layer is however quickly developed during acid passivation treatments. There may be circumstances when the pickling and passivation processes occur sequentially (not simultaneously), during acid treatments involving nitric acid. Nitric acid alone will only passivate stainless steel surfaces. It is not an effective acid for pickling stainless steels.

Pickling

Passivating and PicklingPickling is the removal of a thin layer of metal from the surface of the stainless steel. Mixtures of nitric and hydrofluoric acids are usually used for pickling stainless steels. Pickling is the process used to remove weld heat tinted layers from the surface of stainless steel fabrications, where the steel's surface chromium level has been reduced.

Stainless steel surfaces have a unique self-healing surface protection system. The transparent passive layer quickly reforms if damaged, provided there is sufficient oxygen in the surroundings. Surface coatings or corrosion protection systems are not normally needed for stainless steels to perform as naturally corrosion resistant materials.

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