1, hot-galvanized zinc layer is thick, about above 10um, strong anti-corrosion ability. so is a commonly used galvanized process. zinc plating is thin, about 3-5um, hot-dip galvanized surface roughness, bright, serious spangle, electroplate is smooth, dark (dirty). Electroplating manufacture galvanized steel with good machinability. but to a thin coating, corrosion resistance than the hot-dip galvanized plate. Cold galvanized sheet is galvanized, galvanized is so small that only the outer tube wall galvanized (hot-dip galvanized---coating both inside and outside), 10-50g/m2, its own specific heat galvanized pipe corrosion resistance difference.
2, chemical plating of zinc more suitable for small parts hot galvanized plate used in electrical equipment and components, suitable for large parts and equipment. Zinc electroplating, commonly known as cold galvanized sheet, electrochemical approach is adopted, the zinc anode, zinc atoms lose electrons to become ions dissolved in the electrolyte, and steel as the cathode, zinc ions in iron and steel with electron reduced to zinc atoms deposited on the metal surface, forming coating. Hot-galvanized sheet is the first steel pickling, in order to remove surface oxide, after pickling, by aqueous solution of ammonium chloride and zinc chloride or ammonium chloride and zinc chloride mixed with water in the solution tank for cleaning, and then into hot-dip tanks.
3, hot galvanized plate and galvanized sheet zinc-plating there is a big difference. Hot galvanized zinc plating cannot be too small, generally a minimum of 50~60g/m2 on both sides, can be up to 600g/m2. Galvanized sheet galvanized layer can be very thin, minimum 15G/m2, but requires thicker coating production line speed is very slow, not adapted to the technological characteristics of the modernization unit, generally up to about lO0g/m2. Because of this, galvanized sheet production was very limited.
4, hot galvanized plate and galvanized sheet on the coating structure is fundamentally different. Hot-dip galvanizing slab zinc coating and steel substrate with a slightly crunchy layer of compound layer, crystals are formed when pure zinc coating zinc flower, coating evenly without pores. Zinc plating zinc atoms deposited on steel strip surface precipitation, and physical effects attached to the metal surface, there are many holes out, easily pitting due to corrosive media, hot-dipped galvanized sheet is more resistant to corrosion than zinc plating.
5, and hot plating zinc Board and plating zinc Board of heat treatment process also completely different, hot plating zinc Board Board General to cold hard for raw materials, in plating zinc line Shang continuous for annealing and hot plating zinc Board, steel with in short Shi smell within heating Hou and cooling, so strength and plastic by must of effect, its stamping performance than also of cold hard by professional line skim annealing Hou of cold rolled Board poor. Cold rolled sheet as raw material of galvanized sheet, basically ensure that cold-rolled sheet processing performance, but its complex process also increases the cost of production. In short, hot-dip galvanized sheet production at lower costs, a wide range of applications, also galvanized the main varieties.
6, heat galvanized pipe is the molten metal reacts with iron matrix alloy layer, so that the substrate and the coating combination. Hot galvanized plate with uniform coating, adhesion, long life and other advantages.