What is the difference between hot dip galvanized steel pipe and cold dip galvanized steel pipe

Galvanized steel pipe is divided into two categories ： hot dip galvanized steel pipe and cold-galvanized steel pipe. Cold-dip galvanized steel pipe is electro-galvanized steel pipe. The content of galvanizing is very small, only about 10g to 20g per square meter. Its corrosion resistance is not as good as that of hot-dip galvanized steel pipe; the corrosion resistance of hot-dip galvanized steel pipe is greater than that of cold-dip galvanized steel pipe. Besides, what are the differences between the two?

The difference between hot-dip galvanized steel pipe and cold galvanized steel pipe

1. The two are very different in their mode of operation. The zinc used in hot-dip galvanizing is obtained at a temperature of 450℃ to 480℃; while the zinc in cold galvanized steel pipe is obtained by electroplating process at room temperature.

2.Cold galvanized pipe and hot galvanized pipe in the thickness of the galvanized layer has a big difference, the thickness of zinc in hot galvanized steel pipe is greater than the thickness of zinc in cold galvanized steel pipe.

3.The surface smoothness of the two are different, cold galvanized steel pipe surface compared to hot galvanized steel pipe is much rougher.

4.Cold galvanized pipe and hot-dip galvanized pipe in the price above also has a big difference. In order to ensure the quality, the manufacturer generally does not use the galvanizing method of electro-galvanizing for hot-dip galvanized steel pipes.; and those relatively obsolete equipment of small-scale enterprises, most of them will use electro-galvanized this way, and thus the price of cold galvanized steel pipe is lower than hot-dip galvanized steel pipe.

5.Hot-dip galvanized steel pipe is the steel pipe is fully galvanized, while cold galvanized steel pipe is galvanized only one side of the steel pipe.

6. The adhesion of the two is also very different. Cold galvanized steel pipe adhesion than the adhesion of hot-dip galvanized steel pipe is poor, because the cold galvanized steel pipe steel pipe matrix and the zinc layer is independent of each other, the zinc layer is very thin, and is still simply attached to the surface of the steel pipe matrix, it is very easy to fall off.

The process of cold galvanized steel pipe is electroplating, the inner wall of the steel pipe is not galvanized, only the outer wall of the steel pipe is coated with zinc; the process of hot-dip galvanized steel pipe is hot-dip galvanizing, and the inner and outer walls of the pipe have a zinc layer. According to the relevant regulations of the country, cold-galvanized pipes have poor corrosion resistance, and the zinc layer is easy to fall off, posing safety hazards, so they cannot be used as gas pipes and water pipes.

In conclusion, the difference between the two is the different thickness of zinc, the different smoothness, the different price, the different corrosion resistance and the different adhesion.