Out-of-line annealing means that the recrystallization annealing of hot or cold rolled steel plate is carried out in the bottom type annealing furnace or cover type annealing furnace before entering the hot plating wire line, so that there is no annealing process in the galvanized line. The steel plate must maintain a clean active surface of pure iron, free of oxides and other dirt, before hot dip galvanizing. In this method, the annealed surface oxide sheet is first removed by pickling method, and then coated with a layer of zinc chloride or a mixture of ammonium chloride and zinc chloride solvent for protection, so as to prevent the plate from being oxidized again.

In the process of composite plating, it is necessary to stir the plating solution to obtain the composite coating in which the particles dispersed in the matrix metal. Stirring methods include mechanical stirring, air stirring, ultrasonic stirring, bath circulation, etc. In the process of production, the acid activation solution can remove the corrosion products and oxide film on the surface of low carbon steel wire without excessive corrosion on the matrix. Galvanized wire can be used zincate galvanized or chloride galvanized and other processes, appropriate additives should be used to obtain the coating required by the standards of low carbon steel wire.