Galvanized Pipe

Galvanized pipe, also known as galvanized steel pipe, comes in two types: hot-dip galvanized and electro-galvanized. Hot-dip galvanized pipe has a thicker zinc coating, offering advantages such as uniform coating, strong adhesion, and long service life. Electro-galvanized pipe is cheaper, but its surface is not as smooth, and its corrosion resistance is significantly lower than that of hot-dip galvanized pipe.

Cold-dip galvanized pipe, also known as electro-galvanized pipe, has a very low zinc coating, only 10-50 g/m², and its corrosion resistance is significantly lower than that of hot-dip galvanized pipe. Reputable galvanized pipe manufacturers mostly avoid electro-galvanizing (cold galvanizing) to ensure quality. Only small-scale enterprises with outdated equipment use electro-galvanizing, and their prices are relatively cheaper. Cold-dip galvanized pipe is no longer permitted for use as water or gas pipes.

Hot-dip galvanized steel pipe undergoes a complex physical and chemical reaction with the molten zinc bath, forming a corrosion-resistant, tightly structured zinc-iron alloy layer. This alloy layer is fused with the pure zinc layer and the steel pipe substrate, resulting in strong corrosion resistance.

Cold-galvanized steel pipes have an electroplated zinc layer that is separate from the steel pipe substrate. This thin zinc layer adheres simply to the substrate and is prone to peeling off. Therefore, it has poor corrosion resistance. Cold-galvanized steel pipes are prohibited from being used as water supply pipes in newly constructed residential buildings.