Advantages of hot dip galvanizing

The advantage of hot-dip galvanizing is that it has a long anti-corrosion life and is adaptable to a wide range of environments. It is a popular anti-corrosion treatment method. The specific advantages are as follows:

1. The coating is complete and uniform:

  The entire steel surface is protected, and the molten zinc is easily and evenly covered whether it is inside the recessed pipe fitting or any corner where other coatings are difficult to penetrate.

2. The coating is hard: The hardness of the galvanized layer is greater than that of steel. The uppermost Eta layer only has a hardness of 70 DPN, so it is easily dented by collisions, but the lower Zeta layer and delta layer have hardness values of 179 and 211 DPN respectively, which are higher than the 159 DPN hardness of iron, so they are impact and resistant. The wear properties are quite good.

3. Unique corner protection In the corner areas, the zinc layer is often thicker than elsewhere and has good toughness and wear resistance. The corners of other coatings are often the thinnest, most difficult to apply, and most vulnerable to damage, so they often need to be maintained.

4.Double protection: barrier and sacrificial anode protect cathode. Even if a small part of the zinc layer falls off due to heavy mechanical damage or other reasons, the iron base will be exposed. At this time, the surrounding zinc layer will function as a sacrificial anode to protect the steel here from corrosion. On the other hand, the opposite is true for other coatings. Rust will form immediately and quickly spread underneath the coating, causing the coating to peel off.

5. The zinc layer is consumed very slowly in the atmosphere, and the zinc layer will also corrode, but the corrosion rate is about 1/17 to 1/18 of the corrosion rate of steel, and it is predictable, and its lifespan is far longer than that of any other coating. layer. Usually the electroplated zinc layer has a thickness of 5 to 15 μm, while the hot-dip galvanized layer is generally above 35 μm or even as high as 200 μm. Hot-dip galvanizing has good covering ability, dense coating and no organic inclusions. As we all know, the mechanism of zinc's resistance to atmospheric corrosion includes mechanical protection and electrochemical protection. Under atmospheric corrosion conditions, there are protective films of ZnO, Zn(OH)2 and basic zinc carbonate on the surface of the zinc layer, which slow down the corrosion of zinc to a certain extent. This If the first layer of protective film (also called white rust) is damaged, a new film layer will be formed. When the zinc layer is severely damaged and endangers the iron matrix, zinc will electrochemically protect the matrix. The standard potential of zinc is -0.76V and the standard potential of iron is -0.44V. When zinc and iron form a micro-battery, zinc is dissolved as an anode and iron Protected as cathode. Obviously, hot-dip galvanizing has better resistance to atmospheric corrosion of base metal iron than electro-galvanizing. 6. Hot-dip galvanizing has a long anti-corrosion life

The anti-corrosion life of hot-dip galvanized products varies in different environments: 13 years in heavy industrial areas, 50 years in the ocean, 104 years in the suburbs, and 30 years in the city. The coating life span depends on the thickness of the coating in a specific environment. The thickness of the coating is determined by the thickness of the steel. That is, the thicker the steel, the easier it is to get a thicker coating. Therefore, the thicker steel parts in the same steel structure must also get a thicker coating to ensure a longer life.