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

Galvanized steel pipes are divided into two categories: hot-dip galvanized Steel Pipes and cold-dip galvanized steel pipes.

Cold-dip galvanized steel pipes are electro-galvanized steel pipes. The zinc content is very small, only about 10g to 20g per square meter, and its corrosion resistance is not as good as that of hot-dip galvanized steel pipes; the corrosion resistance of hot-dip galvanized steel pipes is greater than that of cold-dip galvanized steel pipes. In addition, what are the differences between the two?

Differences between hot-dip galvanized steel pipes and cold-dip galvanized steel pipes
First: The two have very different working methods. The zinc used in hot-dip galvanizing is obtained at a temperature of 450℃ to 480℃; while the zinc in cold-dip galvanized steel pipes is obtained through an electroplating process at room temperature.

Second: There is a big difference in the thickness of the galvanized layer between cold-dip galvanized pipes and hot-dip galvanized pipes. The thickness of zinc in hot-dip galvanized steel pipes is greater than that in cold-dip galvanized steel pipes.

Third: The surface smoothness of the two is different. The surface of cold-dip galvanized steel pipe is much rougher than that of hot-dip galvanized steel pipe.

Fourth: There is also a big difference in price between cold-dip galvanized pipes and hot-dip galvanized pipes. In order to ensure quality, manufacturers generally do not use electrogalvanizing for hot-dip galvanized steel pipes; and those small-scale enterprises with relatively old equipment mostly use electrogalvanizing. Therefore, the price of cold-dip galvanized steel pipes is lower than that of hot-dip galvanized steel pipes. The hot-dip galvanized pipes supplied by Xinteng Industrial Products Procurement MRO Mall are all produced by regular manufacturers, and the quality is guaranteed.

Fifth: Hot-dip galvanized steel pipes are galvanized on all sides of the steel pipe, while cold-dip galvanized steel pipes are only galvanized on one side of the steel pipe.

Sixth: There is also a big difference in the adhesion of the two. The adhesion of cold-dip galvanized steel pipes is worse than that of hot-dip galvanized steel pipes, because the steel pipe matrix and the zinc layer of cold-dip galvanized steel pipes are independent of each other, the zinc layer is very thin, and it is simply attached to the surface of the steel pipe matrix, and it is easy to fall off.

The process used for cold-dip galvanized steel pipes is electroplating, and the inner wall of the steel pipe is not galvanized, only the outer wall of the steel pipe is zinc-plated; the process used for hot-dip galvanized steel pipes is hot-dip galvanizing, and there are zinc layers on the inner and outer walls of the pipe. The state has made relevant regulations that cold-dip galvanized pipes have poor corrosion resistance, and the zinc layer is easy to fall off, which poses a safety hazard, so they cannot be used as gas pipes and water pipes.

In summary, the difference between the two lies in the different zinc thickness, smoothness, price, corrosion resistance, and adhesion.