Hot dip galvanizing is to make the molten metal react with the iron matrix to produce an alloy layer, so that the matrix and the coating are combined. Hot dip galvanizing is to first pickling the iron and steel parts. In order to remove the iron oxide on the surface of the iron and steel parts, after pickling, it is cleaned in the tank of ammonium chloride or zinc chloride aqueous solution or mixed aqueous solution of ammonium chloride and zinc chloride, and then sent into the hot dip plating tank. Hot dip galvanizing has the advantages of uniform coating, strong adhesion and long service life.
The entire steel surface is protected, and the melted zinc is easily coated evenly, whether in the interior of the pipe fitting in a depression, or in any other corner where the coating is difficult to access. The hardness of galvanized coating is greater than that of steel. The Eta layer of the upper layer of Z is only 70 DPN hardness, so it is easy to be dented by collisions. However, the hardness values of the lower layer of Zeta layer and delta layer are 179 and 211 DPN respectively, which are higher than that of the iron material of 159 DPN. Therefore, its impact resistance and wear resistance are quite good.
In the corner area, the zinc layer is often thicker than other places, and has good toughness and abrasion resistance. And other coatings in this corner, often Z thin Z is not easy to construction, Z is easy to hurt, so often need to be maintained. Even if there’s a lot of mechanical damage or something. Causing a small layer of zinc to peel off, leaving the iron base exposed, the surrounding zinc layer will act as a sacrificial anode to protect the steel from erosion.
With other coatings, the opposite is true. Rust builds up immediately and spreads quickly underneath the coating, causing it to peel. The depletion of zinc in the atmosphere is very slow, about 1/17 to 1/18 of the corrosion rate of steel, and is predictable. Its life span far exceeds that of any other coating. The life of the coating depends on the thickness of the coating in a particular environment. And the coating thickness is determined by the thickness of the steel, that is, the thicker the steel is easy to get thicker coating, so the thick steel part of the same steel structure must also get thicker coating, in order to ensure a longer life.
Because of the beauty, art, or in specific severe corrosion environment, galvanized layer can be applied to the above paint duplex system, as long as the paint system selection is correct, easy construction, its anticorrosion effect is 1.5~2.5 times better than the single paint and hot dip zinc life combined. With zinc layer to protect iron and steel, in addition to hot dip galvanizing method, there are several other methods, generally widely used, corrosion prevention effect is good and good economic benefits, hot dip galvanizing method.
Post time: 12-12-22