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Hot dip galvanized vs galvanized

What is hot dip galvanized 

Hot dip galvanizied is the process of coating iron or steel with a layer of zinc by immersing the metal in a bath of molten zinc at a temperature of around  450 °C (842 °F). During the process, a metallurgically bonded coating is formed which protects the steel from harsh environments, whether they be external or internal.

Galvanized steel is widely used in applications where corrosion resistance is needed without the cost of stainless steel and can be identified by the crystallised pattern on the surface (often called a ‘spangle’). Galvanizing is probably the most environmentally friendly process available to prevent corrosion.

What is galvanized 

Galvanized is usually referred to as electrogalvanization or cold galvanizing. Electrogalvanization is done by immersing steel in a bath of saline and zinc. Electricity is applied to the solution, which causes electrons from the zinc to bond to the steel. The zinc forms a layer on top of the steel that protects against corrosion.

The process gives your material a smooth, attractive finish. However, that finish won’t be nearly as durable as a finish produced by hot dip galvanization.

Advantages of electro galvanization include:

  • More cost-effective than hot dipped galvanization
  • The coating produced is uniform
  • Leaves a clean finish that is attractive and appropriate for architectural applications where aesthetics are a priority

Cold galvanizing refers to the surface of steel materials coated with zinc rich paint, this method only needs the usual paint used equipment, but the durability and service life of zinc layer (called zinc rich coating) is poor, the sacrifice of steel materials to provide protection is less.

Hot dip galvanized is a very simple process that provides long term corrosion protection to steelwork.

hot dip galvanized steel-900
hot dip galvanized steel

Hot dip galvanized is widely used in many industries, such as construction, machinery, railway, etc., the surface of this product has hot dip plating, can enhance the ability to resist corrosion, and prolong the life, greatly save the cost, so what are the advantages of this product?

The advantages of Hot dip galvanized product

1. Hot dip galvanized protects the entire steel surface, and the dissolved zinc can be easily covered evenly on the inside of the pipe fittings in the depression or any other corner where the coating is difficult to enter.

2. The hardness of hot dip galvanized layer is greater than that of steel. The hardness of the top layer of Eta layer is only 70 DPN, so it is easy to be Dave by impact. However, the hardness of the bottom layer of Zeta layer and delta layer are 179 and 211 DPN respectively, which are higher than that of 159 DPN of iron, so the impact resistance and wear resistance of the layer are quite good.

3. In the corner area, the zinc layer is often thicker than other places, and has good toughness and wear resistance. And other coatings in this corner, is often the thinnest, the most difficult to construct, the most vulnerable to injury, so often must be maintained again.

4. In the case of hot dip galvanized method, even if it is due to severe mechanical damage or other reasons. This causes a small portion of the zinc layer to fall off, exposing the iron base. At this point, the surrounding zinc layer acts as a sacrificial anode, protecting the steel from erosion. While other coating is just the opposite, rust will be immediately formed, and quickly spread to the coating below, causing coating peeling.

hot dip galvanized billboards with space grid structure-900
hot dip galvanized billboards with space grid structure

5. The depletion of zinc layer in the atmosphere is very slow, about 1/17 to 1/18 of the corrosion rate of steel, and it can be predicted. Its life is far longer than that of any other coating.

6. The life of the hot dip galvanizing coating depends on the thickness of the coating in a particular environment. The thickness of the coating is determined by the thickness of the steel, that is, the thicker the steel is easy to get a thicker coating, so the thickness of the steel part in the same steel structure must also get a thicker coating, in order to ensure a longer life.

7. Duplex system can be applied to the galvanized layer for aesthetic, artistic, or specific severe corrosive environments. As long as the paint system is correctly selected and easy to be applied, the corrosion prevention effect will be 1.5~2.5 times better than the combined life of single painting and hot dip galvanized.

8 with zinc layer to protect steel, in addition to hot dip galvanized method, there are several other methods, generally the most widely used, the best corrosion prevention effect and the best economic benefits, for hot dip galvanizing method.

hot dip galvanized billboards with space grid structure-900a
The hot dip galvanized billboard of space grid structure is loaded into the container

At present, hot dip galvanized products are mainly steel plate, steel strip, steel wire, steel pipe, which hot dip galvanized steel plate accounted for the largest proportion. For a long time, hot dip galvanizing process is favored by people because of its low plating cost, excellent protection characteristics and beautiful appearance. Because the hot dip galvanized material has the above 8 advantages, so a BIGTREE outdoor billboards using hot dip galvanized steel, so that BIGTREE outdoor billboards have a long service life, low maintenance cost, friendly to the environment.

BIG TREE are among the leading hot dip galvanized billboards manufacturers in the China. Being in the business for two decades, the company offers a wide range of products including LED advertising screen billboard, bus shelters, outdoor billboards, street furniture, led display billboard, light box,etc. Till now our products have been successfully exported to over 35 countries.

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