First, Classification of Galvanized Steel Pipes
1. Hot-dip galvanized steel pipes: Galvanizing involves reacting molten metal with the iron substrate to create an alloy layer, bonding the substrate and coating. Hot-dip galvanizing first requires pickling to remove iron oxide from the pipe surface, followed by cleaning with an ammonium chloride or zinc chloride solution before immersion in a hot-dip galvanizing bath. Hot-dip galvanized pipes produce a more uniform coating with stronger adsorption capacity and a longer lifespan.
2. Cold-dip galvanized steel pipes: Cold galvanizing, also known as electro-galvanizing, involves a smaller amount of zinc plating, resulting in significantly lower corrosion resistance and a shorter lifespan compared to hot-dip galvanized steel pipes.
3. Hot-dip galvanized steel pipes: Galvanized steel pipes form a zinc-iron alloy layer through reaction between the steel pipe and the galvanizing solution. This alloy layer, along with the pure zinc layer and the steel pipe, is integrated, resulting in strong corrosion resistance.
4. Cold-dip galvanized steel pipes. The zinc layer and the steel pipe are separate layers. The zinc layer is relatively thin and simply adheres to the surface of the steel pipe, making it prone to peeling. Therefore, cold-galvanized steel pipes are not permitted as water pipes.

Secondly, the main uses of galvanized steel pipes are.
Galvanized steel pipes are commonly used for gas and heating systems. While they are also used as water pipes, after a few years, they accumulate a large amount of rust. The resulting yellow water not only stains sanitary wares but also allows bacteria to grow on the inner walls. Rust also causes heavy metal content in the water to exceed standards, further endangering human health. My country's Ministry of Construction prohibited the use of galvanized steel pipes as water pipes starting in 2000.

Thirdly, the technological characteristics of galvanized steel pipes.
Sulfate zinc plating has the advantage of 100% current utilization and a very fast deposition rate. However, because the coating crystals are not fine enough, its deep plating capability is poor, making it only suitable for pipes and wires with simple geometric shapes. Through process improvements, iron salts have been added to the original solution, inheriting the advantages of traditional sulfate zinc plating while enhancing its deep plating capability. Through continuous improvements, the coating grains used for wires and pipes are now finer and shinier than before.