Hot dip galvanizing is the reaction of a molten metal with an iron matrix to produce an alloy layer, thereby combining the substrate and the plating. Hot-dip galvanizing is the first step of pickling steel parts in order to remove iron oxide on the surface of steel parts. After pickling, it is cleaned by ammonium chloride or zinc chloride aqueous solution or mixed solution of ammonium chloride and zinc chloride. And then sent to the hot dip plating tank. Hot-dip galvanizing has the advantages of uniform plating, strong adhesion and long service life.
The principle of hot dip galvanizing, in simple terms, is that the cleaned iron parts are immersed in a zinc bath by the wetting action of the plating agent to react the steel with the molten zinc to form an alloyed film. Good hot-dip galvanizing operations should be carried out under the strict control of each process. If the operation of the previous process is not good, it will cause a chain reaction of the subsequent process, and a large increase in operating costs or cause poor hot dip galvanized products. If the pretreatment is poor, the molten zinc cannot completely react with the steel normally, forming the most perfect galvanized coating structure. If the post-treatment is poor, the appearance of the galvanized coating is destroyed, and the value of the product is lowered.
