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The difference between hot-dip galvanized sheet and cold-dip galvanized sheet
Jun 05, 2017

1. Hot-dip galvanized sheet generally thick zinc layer, more than 10um, corrosion resistance is strong. So it is a commonly used zinc plating process. And electroplating zinc is very thin, about 3-5um, hot-plated surface roughness, bright, serious people have zinc flowers, electroplating is smooth, gray (dirty). Electroplating Galvanized steel plate has good processability. But the coating is thinner, and the corrosion resistance is not as hot-dip galvanized sheet. The cold galvanized sheet is galvanization zinc, the galvanization quantity is few, only outside the tube wall galvanization (Hot plating--both inside and outside), only 10-50g, its own corrosion-resistant specific heat galvanized plate tube difference is many.

2. The chemical general galvanization is more, is suitable for the small component; The hot galvanized sheet is generally used for power equipment and components, and is suitable for large parts and equipment. Electroplating zinc commonly known as cold galvanized sheet, is the use of electrochemical methods, zinc ingots as the anode, zinc atoms after the loss of electrons into the ionic state dissolved into the electrolyte, and the steel belt as a cathode, zinc ions on the steel strip to be reduced to the metal deposited into the steel strip surface, forming a coating. Hot-Dip Galvanized sheet is the first steel pipe pickling, in order to remove iron oxide on the surface of steel pipe, after pickling, through ammonium chloride or zinc chloride aqueous solution or ammonium chloride and zinc chloride mixed water solution tank in the cleaning, and then into the hot dip bath.

3. Hot-DIP galvanized plate and galvanized plate in the amount of zinc is very different. The galvanizing quantity of hot galvanized plate cannot be too small, the general minimum is double-sided 50, the maximum can reach 600g M2. and galvanized zinc plate galvanized layer can be very thin, the smallest up to 15g M2, but the thickness of the required coating line is very slow, do not adapt to the modern unit process characteristics, generally the largest Lok M2 around. Because of this, the production of galvanized plate is greatly limited.

4. Hot-Dip Galvanized sheet and galvanized sheet are fundamentally different in the microstructure of the plating. There is a slightly brittle compound layer between the pure zinc coating and the steel strip substrate of the hot dip galvanized sheet, and the pure zinc coating mostly forms the zinc flower, and the coating is even without porosity. and galvanized zinc layer of zinc atoms only in the steel strip surface deposition, and rely on the physical role attached to the surface of the steel belt, there are many holes to dry, very easy due to corrosive medium caused pitting, so hot-dip galvanized plate than galvanized plate more corrosion-resistant.

5. Hot-Dip galvanized sheet and galvanized plate heat treatment process is also completely different, hot-dip galvanized plate generally used cold hard metal as raw material, in the galvanized line continuous annealing and hot galvanized plate, steel band in the short time after the heating and cooling, so the strength and plasticity of a certain impact, its stamping performance than the same cold hard plate by the professional production line after the cold rolling sheet difference. Galvanized sheet to cold-rolled plate as raw material, basically ensure the same processing performance of cold-rolled plate, but its complex process also increased production costs. In short, the production cost of hot-dip galvanized sheet is lower, the application scope is wider, also become the main variety of galvanized sheet market.

6. Hot-Dip Galvanized sheet tube is to make molten metal and iron-based body reaction to produce alloy layer, so that the substrate and the coating both. Hot-Dip Galvanized sheet has the advantages of uniform coating, strong adhesion and long service life. Regular galvanized pipe manufacturers, in order to ensure the quality, most do not use zinc plating (cold plating). Only those small, old-fashioned equipment used galvanization zinc, of course their prices are relatively cheap. The Ministry of Construction has been formally below, the elimination of technical backwardness of the cold galvanized sheet tube, not allowed to use cold galvanized sheet tube for water, gas pipes. Generally now used galvanized plate is hot galvanized plate, and electric wire groove and so on is the cold galvanized sheet, color has a certain difference.