MAY 2021

Difference between hot-dip galvanizing and electro galvanization

Whenever you come across galvanized finished products, normally two things would come to your mind – Hot Dip Galvanizing And Electro Galvanization. Before we move ahead, it is essential to understand what Galvanization is.

Difference between hot-dip galvanizing and electro galvanization

The galvanization process refers to the methodology in which a protective layer of zinc is applied or coated on the iron or steel material. With this process, the metallic substances can be protected from rusting. There are several applications of the galvanization technique which makes them extremely popular. Galvanization techniques can be used for coating pipelines and various metallic instruments and equipment from rusting.

The two most commonly used techniques for the purpose of galvanization are stated to be electro-galvanizing and hot-dip galvanizing. Both the techniques have different advantages and features which make them different from each other. So let’s check out what are the things that make them different from each other.

#1 The Difference In The Process Of Applying The Zinc Layer:

In the Hot-Dip Galvanization process, the layer of zinc is applied to the metallic surfaces in order to protect them from corrosion. In the process, the metallic substance is completely dipped in the bath of molten zinc. The Hot Dip Galvanization process is used by various industries because of the low cost, and the convenience of the process. The temperature is kept at 850 to 900 degrees in order to form the bond of zinc with other metallic substances.

Besides hot-dip galvanization, electro galvanization technique also focuses on the application of a strong zinc layer on the metallic substances, but in a different way. The layer of protective zinc coat is applied by using a current of electricity. The layer formed is thinner than hot-dip galvanizing, making it unsuitable for outdoor applications.

#2 Formation Of The Zinc Layer:

When the zinc layer is formed on the metallic surfaces by using the electro-galvanized technique, the thickness of the zinc layer is about 3 to 6 microns. In some special requirements, the thickness can also reach up to 7 to 8 microns.

If instead of electro galvanization, the hot-dip technique is used, then the thickness of the zinc layer would be generally more than 50 microns. The thickness can also go up to 100 microns.

#3 The Cleaning Process:

If you are using the hot-dip galvanization process, then you need to ensure that a rigid cleaning process should be followed, which includes 7 to 8 bath processes. The metallic surfaces are cleaned thoroughly in alkaline solution, pickling, water rinsing, fluxing. Whereas if you wish to go with an electro galvanization process, then there is no requirement for any sort of stringent cleaning method.

#4 The Life Expectancy Of The Products:

Generally, the layer formed by electro galvanization is extremely thin, hence the life expectancy of the layer is low (just several years) as compared to the hot-dip galvanization process. Hot-dip galvanization is known to have a very high life averaging between 20 to 50 years.

#5 Final Finish Of The Metallic Substances:

If you want to have an excellent finish of the final product, then always opt for electro galvanization. The layer of zinc formed would be uniform, shining, and pleasant. Whereas the hot-dip galvanization process will create a dull, non-uniform, and unpleasant finish.

#6 Different Applications Of The Galvanization Process:

Generally, the hot-dip galvanization technique is used for metallic substances of all sizes, whereas electro-galvanization is suitable exclusively for smaller components.

#7 Effect of Galvanization Process On Steel Surfaces:

When the hot-dip galvanization process is used on the steel surfaces, it will form an alloy of Fe-Zn and leave behind the coating the pure zinc on the surface. The alloy is extremely hard, which protects the coating from abrasion. If the electro galvanization technique is used for steel, then it will form a zinc layer, which will not form a strong bond with steel metallurgically. Hence, for steel surfaces, the hot-dip galvanization process is considered best.

Difference between hot-dip galvanizing and electro galvanization


Now you know about both the techniques of galvanization. The hot-dip galvanization process would be beneficial because its corrosion protection, adhesion, and hardness of zinc coating are better whereas electro-galvanization would be beneficial in terms of brightness and uniformity, which makes it aesthetically appealing. You can make the choice based on your requirements and the material you wish to coat. You can also take into consideration various other factors before you make the final choice.

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