The process that steel pipe is coated with protective corrosion-resistant and rust-resistance zinc layer is known as galvanization. There are three common methods of galvanization:

1. Hot-dipped galvanizing

2. Pre-galvanizing

3. Electro-galvanizing

Hot-dipped galvanization:

The hot dipped galvanizing process is generally put a formed steel product, such as steel tube or steel pipe, dipped in a zinc bath. The steel pipe in the zinc bath will have a chemical reaction with the zinc layer. The quality of the zinc layer coating is influenced by a number of factors. For example, the surface of the steel products, the time the steel products dipped in the bath, and the composition of the steel as well as the steel's size and thickness.

One advantage of hot dip galvanizing is the methods giving the steel products an all-around corrosion and rust protection. The finished products can be used outdoors in all different weather conditions. Hot-dipped galvanization has become the most popular galvanizing method and the hot dipped galvanized pipe has been widely used in the construction industry.

Pre-galvanization:

Pre-galvanization refers to galvanization prior to further manufacturing. Pre-galvanization is also known as mill galvanized as the steel sheet is rolled through molten zinc. After the sheet is sent through the mill to be galvanized it is cut to size and recoiled. One of the advantages which pre-galvanized steel has over hot-dip galvanized steel is that it has a better appearance. Pre-galvanized steel pipe is used for a wide variety of construction projects.

Electro-galvanized steel:

Electro-galvanization is also be named cold-galvanization. It refers to methods applying a zinc coat deposited onto the steel by using electrodeposition. Electro-galvanized steel has the advantage that the coating thickness can be controlled independently on the internal and external parts. The thickness of the zinc layer applied by electro galvanization is precise. The cold galvanized steel pipe is the main materials using in liquid transport before the hot-dipped galvanized steel pipes’ mass production.