Hot-dip galvanized steel pipe is another name we often call the iron strapping. Zinc plating is an important process in the production of galvanized strapping, 2 inch steel pipe for sale. And we all know that galvanizing is divided into cold galvanizing and hot galvanizing. What is the difference between the two?
1. Hot-dip galvanizing, also known as hot-dip galvanizing, is the process of degreasing and derusting the workpiece to present a non-staining and wetting surface. It is immediately immersed in a plating tank which is previously melted by zinc and formed on the surface of the workpiece. A method of zinc plating. Cold-galvanizing is the process of immersing the workpiece, which has been degreased and decontaminated, into a special plating tank, and the anode is zinc. The method of turning on the direct current power source, the zinc ions on the anode migrate to the cathode, and discharging on the cathode, so that the workpiece is plated with a zinc layer of hot-dip galvanized steel strands.
2. The hot-dip galvanized coating is thicker, generally 30-60 microns, and the coating has high corrosion resistance. The cold galvanized coating is anti-corrosive by the electrochemical principle, so it is necessary to ensure sufficient contact between the zinc powder and the steel to produce an electrode potential difference.
In general, galvanized straps are hot-dip galvanized. Of course, some will choose cold galvanizing. The galvanizing method is different. Naturally, the use of 150×150 square tube weight natural straps will be slightly different, so we are choosing at the time of purchase, it is also necessary to pay attention to the price of hot-dip galvanizing is cheaper than electro-galvanizing.
Electroplated zinc has a better surface coating adhesion than hot-dip galvanizing. Hot-dip galvanized coatings are higher than electrogalvanized. Electrogalvanizing is normally 20g on one side. Hot-dip galvanizing is at least 30–40g.
The hot-dip galvanized steel pipe is a hot-dip galvanized pipe which reacts a molten metal with an iron matrix to produce an alloy layer, thereby combining the substrate and the plating layer.
Hot-dip galvanizing is to pickle the steel pipe first, in order to remove the iron oxide on the surface of the steel pipe, after pickling, it is washed by ammonium chloride or zinc chloride aqueous solution or a mixed aqueous solution of ammonium chloride and zinc chloride, and then fed. Hot dip plating tank. Hot-dip galvanizing has the advantages of uniform plating, strong adhesion and long service life.
The steel pipe matrix and the molten plating solution undergo complex physical and chemical reactions to form a corrosion-resistant structure of a zinc-iron alloy layer. The alloy layer is integrated with the pure zinc layer and the steel pipe base. Therefore, its corrosion resistance is strong.
1. Uniformity of galvanized layer: The steel pipe sample shall be immersed continuously in the copper sulfate solution for 5 times without redness (copper plating)
2. surface quality: the surface of the galvanized steel pipe should have a complete galvanized layer, there must be no black spots and bubbles that are not plated, allowing for a rough surface and local zinc tumors.
3. Weight of galvanized layer: According to the requirements of the purchaser, the galvanized steel pipe can be used for the weight determination of the zinc layer. The average value should be not less than 500g/m2, and any sample should not be less than 480g/m2.
Cold-galvanized pipe cold-galvanizing is electro-galvanized, with a small amount of galvanizing, only 10-50g/m2, and its corrosion resistance is much worse than that of hot-dip galvanized pipe. Regular galvanized pipe manufacturers, in order to ensure quality, most do not use electro-galvanizing.
Only small companies with small equipment and old equipment use electro-galvanized steel, of course, their prices are relatively cheaper.