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What are the causes of white rust and dark spots?

Dark spots are further oxidation of white rust. The main causes of white rust are:

Poor passivation, passivation film thickness is not enough or uneven; No oil on the surface or residual water on the strip surface; The surface of the strip contains water when it is rolled up. Passivation not completely dried; Getting wet or rain-soaked during transportation or storage; The storage time of finished products is too long; Galvanized sheet and other acid and alkali and other corrosive media contact or stored together.


Zhishang Steel Co., Ltd

ABOUT USOverviewThe company mainly deals in color-coated, galvanized, stainless steel pipes, stainless steel coils, stainless steel plates of various materials; hot-rolled series of rebar, medium and heavy plates, coils, I-beams, angle steels, channel steels, H-beams and other steel products and deep processing Service. (The company’s annual invent···

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