The coating thickness is 8-12 μm. Passivation layer contains trivalent Chrome (Cr-3), which is environmentally friendly. Three different types of passivation/chromating like yellow, olive, and blue chromating are on choice. The inner and outer surface both could be galvanized. Minimum resistance in salt spray test could reach 96 hours according to ISO 9227.

Highly accurate; Cold drawn bright seamless steel tube galvanized against corrosion and red rust; The externally galvanized tubes with a zinc coating subsequently passivated or chromated, to generate a protective layer for zinc layer against white rust; Caps covered at two ends of tube to prevent from dust.