Hot dip galvanized pipe is causes the molten metal and alloy layer andiron substrate reaction and attack so that the substrate and coatingcombination of both. Is hot dip galvanized steel pipes to pickling, inorder to remove iron oxide on the surface of the steel tube after acidpickling, ammonium chloride or zinc chloride or ammonium chloride andzinc chloride mixed aqueous solution to clean in the tank, and thensent to the hot dip plating tank. Hot dip galvanized with uniformcoating, strong adhesion, long life and other interests. With moltensolution attack messy physical, chemical reaction, to form the structuretight a zinc alloy corrosion resistant layer. Pure zinc alloy layer andlayer and steel substrate. So the corrosion resistant ability.