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On the four types of hot dip galvanized fasteners

First, electro galvanized
Galvanizing is the most common fastener products manufacturing in a surface treatment method and technology.
Electro galvanized layer is anode coating typical, mainly used to improve the corrosion resistance of substrate. Because of the coating thickness, coating is mainly applied to the general conditions.
The chromate passivation treatment, the anti-corrosion performance is greatly improved, zinc plating was excellent for outdoor protection neutral playing, but the corrosion in harsh industrial atmosphere and coastal climate performance is worse.
Electro galvanized surface treatment method and process technology, low cost, the technology is stable and reliable, easy to use. However, very easy to produce hydrogen embrittlement phenomenon, so the electric galvanized should be timely to hydrogen treatment. In addition, acid and alkali resistance is poor, preservation time is short, low technology and environmental protection.
Second, powder zinc penetration
Sherardizing is a zinc dipping agent for zinc and zinc source, produced by heating, the iron atom diffusion in the steel surface layer was zinc (Zn Fe alloy layer) surface treatment process.
The main components of sherardizing is pure zinc powder, adding proper amount of filler such as alumina, clay refractory and ammonium chloride.
The most prominent infiltration characteristics of zinc powder is not an external coating, but metal matrix and layer constitute the organic whole, so tightly. Powder penetration hardness and corrosion resistance of zinc layer is much better than that of galvanized layer.
Sherardizing process is surface treated workpieces with powder zincized agent embedded in a sealed container, heated to the melting point of zinc, heat preservation time, and then with the furnace cooling to room temperature.
Infiltration characteristics of zinc powder is the most prominent infiltration layer is uniform, no ammonia, almost no deformation. Particularly suitable for nuts, bolts and other fasteners and hardware products, surface complex shape workpiece and powder metallurgy products processing technology.
Third, mechanical plating
Mechanical zinc in zinc powder and dispersing agent, accelerator, the liquid medium (usually with water) and other substances under the conditions of existence, making the use of impact media (such as glass ball), impact on iron and steel surface, and the formation of galvanized layer surface treatment process on the surface of the product.
Mechanical plating layer and the electro galvanized, an anticorrosive coating formation process of hot dip galvanizing completely different.
Technology characteristics: room temperature operation, by loading parts plating barrel rotation, so that the impact of media in the barrel with the drum rotation, and the parts collide to produce mechanical impact force, the surface of zinc powder collision deposition in the workpiece, thus forming a basic physical characteristics of metallic zinc coating.
Technology characteristics: galvanized process of mechanical galvanizing process does not produce hydrogen embrittlement of high strength steel harm.
Defect: zinc layer thickness is uneven; zinc layer as plating layer of smooth, bright.
Fourth, hot dip galvanizing
Hot dip galvanizing are also known as hot galvanizing
Hot dip galvanizing zinc liquid steel parts is the pre processed into molten, forming on the surface of zinc and (or) Zn Fe alloy coating, so as to obtain the process and methods of metal coating.
Hot dip galvanizing applications of very wide range, such as hot dip galvanizing highway traffic stall (highway guardrail fastener connection), pipes and hot dip galvanized fasteners power transmission widely used and other fastener.
Hot dip galvanizing work life except with the process itself, there is a direct relationship between adhesion and galvanized layer.
Hot dip galvanized layer covering the protective ability, ability against atmospheric corrosion is better than that of zinc plating.