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Steel Protection through Galvanization

7/6/2015 5:42:23 PM | by liannah tsui

Galvanizing Service

A process of applying a protective zinc coating to an iron, aluminum or steel is known as galvanization. It acts like a barrier between the steel and the environment preventing it from rusting caused by moisture and other external factors. There are various methods such as the hot-dip galvanization which is the most common. It is a galvanizing process wherein parts are submerged in a bath of molten zinc. This process protects material by forming a coating of corrosion-resistant zinc and preventing the delicate part to be reached by corrosive substances. The steel galvanization also provides zinc that serves as a sacrificial anode which still protects the steel even when the coating is scratched or exposed to the environment.

Hot dip galvanization produces galvanized sheet metal for used in applications where corrosion resistance is needed. It is the metallurgical bond of the steel and the zinc added to a series of distinct iron-zinc alloys.

Galvanizing service offered by various companies and steel suppliers brings the best protective coating technology for steel to ensure product durability and long life. These companies use machines and equipments that match the design and handling characteristics of steel and deliver an engineered performance result. Galvanizers have learned to be ingenious and inventive in managing complex lengths and shapes. They take different considerations such as the size of the galvanizing baths and the permissible weight that the lifting gear and vehicles used for transport.

Stages for Galvanization
The following are the common stages being followed during the galvanizing process.
1. Degreasing / Rinsing
In degreasing, the steel subjected for galvanizing have residues of oil or grease which is to be removed using the degreaser or other method of cleaning. Acidic degreasing or the aqueous alkaline is commonly employed while washing it after to prevent it from transferring to the second stage.
2. Pickling
This is the process of removing the rust and scale which is used to be the main corrosion elements in a steel fabrication. It is usually applied in dilute hydrochloric acid producing chemically cleaned surface. The time of pickling will depend on the rust concentration on the pickling solution.
3. Rinsing
Rinsing is the process of washing through a water bath in order to minimize the transfer of any acid residues to other processes next to it.
4. Flux Treatment
A final and intensive cleaning of the steel surface is being done and it is known as the flux treatment. It is used to remove all the remaining traces of impurities increasing the wettability of the steel surface. Different ways can be applied such as in the form of aqueous solution where the steel to be galvanized is dipped into it. Other ways include the spraying of the surface in the form of a powder or a liquid.
5. Drying
In this process, the work piece is being dried and a thin film of flux is being coated on to it.
6. Galvanizing
This process is where the bath of molten zinc takes place. It usually works in a temperature ranging 440ºC to 460ºC. This galvanizing stage will lead to the formation of the coating including the zinc-iron alloy.
7. Cooling and Checking
It is the time when the galvanized steel is needed to be immersed in a water bath or to air cool.

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