Classification of galvanized pipes

Galvanized steel pipes are divided into cold plated pipes and hot-dip plated pipes. The former has been banned, while the latter is temporarily promoted for use by the country

Hot dip galvanized pipe

It is the reaction between molten metal and iron substrate to produce an alloy layer, thereby bonding the substrate and coating together. Hot dip galvanizing is the process of first pickling steel pipes. In order to remove iron oxide from the surface of the steel pipes, after pickling, they are cleaned in an ammonium chloride or zinc chloride aqueous solution or a mixed ammonium chloride and zinc chloride aqueous solution tank, and then sent to a hot-dip galvanizing tank. Hot dip galvanizing has the advantages of uniform coating, strong adhesion, and long service life.

Cold galvanized pipe

Cold galvanizing is also known as electroplating galvanizing, with a very small amount of galvanizing, only 10-50g/m2. Its corrosion resistance is much different from that of hot-dip galvanized pipes. Legitimate galvanized pipe manufacturers, in order to ensure quality, mostly do not use electroplating (cold plating). Only small enterprises with small scale and outdated equipment adopt electroplating, and of course, their prices are relatively cheaper. At present, the Ministry of Construction has officially announced the elimination of technologically outdated cold galvanized pipes and prohibits the use of cold galvanized pipes as water and gas pipes in the future.

Hot dip galvanized steel pipe

The steel pipe substrate undergoes complex physical and chemical reactions with the molten plating solution, forming a corrosion-resistant and tightly structured zinc iron alloy layer. The alloy layer is integrated with the pure zinc layer and the steel pipe substrate. Therefore, it has strong corrosion resistance.

Cold galvanized steel pipe

The zinc layer is an electroplating layer, which is independently layered from the steel pipe substrate. The zinc layer is relatively thin and easily adheres to the steel pipe substrate, making it prone to detachment. Therefore, its corrosion resistance is poor. Cold galvanized steel pipes are prohibited from being used as water supply pipes in newly constructed residential buildings.

Galvanized strip rack pipes are mainly used for steel structure racks in high-temperature greenhouses such as vegetable greenhouses. They are cost-effective and have a long service life, making them the preferred product for users