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Introduction To Hot Dip Galvanizing Process

Dec. 09, 2019

Hot-dip galvanizing is the reaction of molten metal with an iron substrate to produce an alloy layer, thereby combining both the substrate and the plating layer. Hot-dip galvanizing is to pickle iron and steel parts first. In order to remove iron oxide on the surface of iron and steel parts, after pickling, it is cleaned in an ammonium chloride or zinc chloride aqueous solution or a mixed solution of ammonium chloride and zinc chloride. And then sent to the hot-dip plating bath. Hot-dip galvanizing has the advantages of uniform coating, strong adhesion, and long service life.


Galvanized Steel Sheet


Galvanized Steel Sheet


Hot-dip galvanizing is one of the most effective means to delay the environmental corrosion of steel materials. It is to immerse the steel products after the surface has been cleaned and activated in molten zinc solution. The surface is coated with a zinc alloy coating with good adhesion. Common steel products include Hot Dipped Galvanized Steel Sheet. Compared with other metal protection methods, the hot-dip galvanizing process has the protective characteristics of the physical barrier and electrochemical protection of the coating, the strength of the combination of the coating and the substrate, the compactness, durability, maintenance-free, and economy of the coating. In terms of its adaptability to the shape and size of the product, it has unparalleled advantages. At present, the hot-dip galvanized products mainly include steel plates, steel strips, steel wires, and steel pipes, among which the hot-dip galvanized steel sheet has the largest proportion. For a long time, the hot-dip galvanizing process has been favored by people for its low plating cost, excellent protection characteristics and beautiful appearance. It is widely used in automobiles, construction, home appliances, chemicals, machinery, petroleum, metallurgy, light industry , Transportation, power, aviation and marine engineering.


What is the principle of hot dip galvanizing? The Galvanized Steel Sheet Manufacturer will tell you that simply put the cleaned iron parts into the zinc bath through the wetting effect of the plating aid, so that the steel and molten zinc react to form an alloyed film. For a good hot-dip galvanizing operation, each process should fully play its role under strict control. And if the operation of the previous process is not good, it will cause a chain of adverse reactions in the subsequent processes, which will increase the operating cost or cause poor hot-dip galvanized products. If the pretreatment is not good, the molten zinc cannot fully react with the steel normally, forming the most perfect galvanized film structure. If the post-treatment is not good, the appearance of the galvanized film is damaged, and the product value is reduced.


Advantages of hot dip galvanizing process:

1. The entire steel surface is protected. No matter the inside of the pipe, or any other corner where the coating is difficult to enter, the molten zinc is easily and uniformly covered.

2. In the corner area, the zinc layer is often thicker than other places, and has good toughness and abrasion resistance. Other coatings at this corner are often the thinnest and least susceptible to construction and the most vulnerable, so they often need to be maintained.

3. Even due to heavy mechanical injury or other reasons. Causes a small part of the zinc layer to fall off and expose the iron base. At this time, the surrounding zinc layer will function as a sacrificial anode to protect the steel here from corrosion. For other coatings, the opposite is true. Rust will form immediately and spread quickly under the coating, causing the coating to peel off.

4. Coating life In a specific environment, it mainly depends on the thickness of the coating. The thickness of the coating is determined by the thickness of the steel, that is, the thicker the steel, the thicker the coating is, the thicker the steel part in the same steel structure must also get the thicker coating to ensure a longer life.

5. Use zinc layer to protect steel. In addition to hot-dip galvanizing, there are several other methods. Generally, the most widely used, the best anti-corrosion effect and the best economic benefits are hot-dip galvanizing, such as Hot Dip Galvanized Steel Coil.


The above is a brief introduction of the hot dip galvanizing process, I hope to help everyone.

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