Zhejiang XinTai Auto Parts Co.,Ltd

what is the intrinsic difference of Electro galvanized and hot dip galvanized (HDG) ?

Zinc plating

Iron and steel in air, water or soil is easy to rust, or even completely damaged. Each year due to corrosion caused by the loss of iron and steel accounted for the entire steel production 1/10, on the other hand, in order to make the steel products and parts of the surface with a special function, and gives the surface decorative appearance, so the general use galvanized the way of its treatment.

First, the principle:

Because zinc is not easy to change in dry air, and in the humid air, the surface can generate a very dense thin film of zinc carbonate, the film can effectively protect the internal corrosion was no longer. And for some reason, when the coating is broken and the exposed steel base is not too large, the zinc and the steel substrate form a micro battery, and the steel substrate is protected by the cathode.

Two, performance characteristics:

1, the zinc coating is thick, the crystal is meticulous, uniform and non porous, good corrosion resistance;

2, the zinc plating layer is pure, in the acid, alkali and other corrosive fog, can effectively protect the steel substrate;

3, zinc coating by chromic acid passivation after the formation of white, color, army green, beautiful and generous, with a certain degree of decoration;

4, due to the zinc coating has good ductility, so can be cold stamping, rolling, bending and other forming without damage to the coating.

Three, the scope of application:

With the development of science and technology, the field of electroplating industry is more and more widely. At present, the application of zinc plating has been all over the country's economic production and research departments. For example, machinery manufacturing, electronics, precision instruments, chemical industry, light industry, transportation, weapons, aerospace, atomic energy, etc., in the national economy is of great significance

Hot dip galvanizing:

I. overview:

In all kinds of protective coating method for steel in hot dip galvanizing is a very good. It is in the state of zinc liquid, after a very complex physical and chemical effects, not only on the steel plating on a thick layer of pure zinc, but also the formation of a zinc iron alloy layer. This plating method not only has galvanized corrosion characteristics, and because of the zinc iron alloy layer. It also has a strong corrosion resistance compared with zinc plating. Therefore, this method is especially suitable for all kinds of strong acid, alkali fog and other strong corrosive environment.

Two, principle: hot dip galvanized layer is zinc in high temperature liquid, formed in three steps:

1, the iron surface is formed by the dissolution of zinc liquid zinc iron alloy layer;

2, the zinc ion in the alloy layer is further diffused to the substrate to form miscible zinc layer;

3, the surface of the alloy layer is covered with zinc layer.

Three, performance characteristics:

(1) a thick, dense, pure zinc layer is covered on the surface of the iron and steel, which can avoid the contact between the steel matrix and any corrosive solution to protect the steel substrate from corrosion. In the general atmosphere, the surface of the zinc layer forms a thin and dense layer of Zinc Oxide, which is difficult to dissolve in water. If Zinc Oxide and other components in the atmosphere to produce insoluble zinc salt, then the corrosion prevention is more ideal.

(2) iron zinc alloy layer, combined with dense, in the marine salt mist atmosphere and industrial atmosphere in the performance of a unique corrosion resistance;

(3) due to the combination of strong, zinc - iron mutual solubility, has a strong wear resistance;

(4) due to the good ductility of the zinc alloy, the alloy layer and the steel substrate are firmly attached, so the hot stamping parts can be used for cold stamping, rolling, drawing, bending, etc.;

(5) after the hot dip galvanizing of steel structure, it is equivalent to the first annealing treatment, which can effectively improve the mechanical properties of the steel matrix, and eliminate the stress of the welding of the steel parts.

(6) the surface of hot galvanizing is bright and beautiful.

(7) the pure zinc layer is the most plastic layer of zinc coating in hot dip galvanizing, its properties are close to that of pure zinc.

Four, the scope of application:

With the development of industry and agriculture, the application of hot galvanizing. Therefore, hot galvanized products in the industry (such as chemical equipment, petroleum processing, marine exploration, metal structure, power transmission, shipbuilding etc.), agriculture (such as irrigation, warm room), construction (such as water and gas transportation, wire tube, scaffolding, housing etc.), bridges, transport and so on, nearly a few years have been widely used. Because of the appearance and corrosion resistance of hot dip galvanized products, its application scope is more and more extensive.