over the door ironing board cover_classic washing machine cover

The application of electric welding net is more widely, at present it has replaced the use of other parts of the wire mesh, the cost of electric welding net is lower, the production speed is very fast, so it is very popular. Welding net galvanized before the need for processing is recrystallization annealing, because the welding net must maintain a no oxide and no other impurities of pure iron active surface, if you can not keep its surface clean will lead to a bad galvanizing effect, galvanized layer and iron material is not closely combined, so this step is necessary.

If the zinc coating is good, but in 3% nitric acid when the light, the coating has dark shadow, passivation occurs when the film is brown, may be caused by foreign metal impurities such as copper or lead in the galvanizing liquid. When problems occur in the process of galvanizing large coil galvanized wire, the temperature and current density are checked first, and then the content of zinc and sodium hydroxide in the plating solution is measured and adjusted through the analysis of the plating solution. Whether DPE content is low can be determined by hull cell test.

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.