The production process of hot galvanized sheet mainly includes: original plate preparation, pretreatment, hot dip plating, post-treatment, finished product inspection, etc. According to custom, hot galvanizing process is divided into two categories, that is, annealing and annealing.

Outside the wire annealing

It is hot or cold rolled steel sheet enters hot galvanization work line before, undertake recrystallization annealing is carried out in the annealing furnace of type of draw bottom or cover type before retreating, such, galvanization line does not exist annealing process. The steel plate must maintain a clean, pure iron active surface free of oxides and other dirt before hot galvanizing. The method is to remove the surface of the annealed sheet metal by pickling, and then apply a layer of zinc chloride or a mixture of ammonium chloride and zinc chloride to protect the steel plate from oxidation. Methods of hot galvanizing fall into this category include: wet hot galvanizing, sheet steel and huilin hot galvanizing.

Wet process

The solvents on the surface of the steel plate do not dry (that is, the surface is still wet) and enter the zinc liquid covering the surface with the molten solvent for hot galvanizing. The disadvantages of this approach are:

Galvanized only in lead-free condition, coating of alloy layer is very thick and adhesion is very bad.

The resulting zinc residue is deposited at the interface between the zinc and the lead and cannot deposit the bottom of the pot (because the zinc residue is larger than the zinc and smaller than the lead), so the steel plate contaminates the surface through the zinc layer. Therefore, this method has been basically eliminated.