Galvanizing

Galvanizing is to improve the corrosion resistance of the steel pipe and extend the service life.

Hot-dip galvanized pipe is made by reacting molten metal with iron substrate to produce an alloy layer, thus combining both the substrate and the plating layer. Hot-dip galvanizing is done by pickling the steel pipe first, in order to remove the iron oxide on the surface of the steel pipe. After pickling, the pipe is cleaned by ammonium chloride or zinc chloride aqueous solution or ammonium chloride and zinc chloride mixed aqueous solution bath, and then sent to the hot dip galvanizing bath. Hot dip galvanizing has the advantages of uniform coating, strong adhesion and long service life.

Cold galvanizing, also known as electro-galvanizing, is the use of electrolytic equipment to put pipe fittings into a solution of zinc salts after degreasing, pickling, and connecting the negative electrode of the electrolytic equipment, and using the directional movement of current from the positive to the negative electrode will deposit a layer of zinc on the pipe fittings. Theoretically, galvanized zinc can reach or even exceed the thickness of hot-dip galvanizing, but in practice, the galvanized zinc layer is generally thinner, resulting in poorer corrosion and rust protection than hot-dip galvanizing, shorter protection life and poorer scratch resistance, but relatively lower cost and brighter appearance than hot-dip galvanizing.