First, the outside of the steel is coated with a solvent to remove external impurities, and then a wire brush is used to remove rust, loose or inclined rust, welding slag, etc., and rust can also be removed by pickling.

Electroplating is divided into thermal plating and cold plating. Hot plating is not easy to rust, cold plating is easy to rust. Of course, galvanized steel pipes are also useful in our daily life.

In fire engineering, the current fire water supply pipe is basically galvanized pipe. The outer layer of the galvanized pipe is coated with a layer of paint, the fire pipe is actually treated by the galvanized pipe, in the steel structure and welding project, many workshops outside the shed have welded steel pipes in front, but the welded steel pipes are easy to rust. Therefore, galvanized steel pipes can reduce the occurrence of rust and make the insulation pipe last a long time.

Difference between hot rolled galvanized steel pipes and cold rolled galvanized steel pipes?

Hot-dip galvanized steel pipe is an alloy layer produced by reacting molten metal with an iron substrate, thus combining both the substrate and the coating. Hot-dip galvanizing is done by first pickling the steel pipe to remove iron oxide from the surface of the pipe, pickling it and then sending it to an aqueous solution of ammonium chloride or zinc chloride or a mixed aqueous solution of ammonium chloride and zinc chloride for cleaning before sending it to a hot dip galvanizing bath. Hot-dip galvanizing has the advantages of uniform coating, strong adhesion and long service life. The hot-dip galvanized steel pipe substrate undergoes a complex physical and chemical reaction with the molten plating solution to form 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, which has a strong corrosion resistance.

Cold galvanized steel pipe is galvanized, the amount of galvanization is very little, only 10-50g/m2, and its own corrosion resistance is much worse than hot dip galvanized just pipe. In order to ensure the quality, the regular galvanized pipe manufacturers generally do not use galvanizing, only those small-scale, old equipment of small enterprises will use galvanizing, and their prices are naturally cheaper. The galvanized layer of cold galvanized steel pipe is an electroplated layer, and the zinc layer is independently layered with the steel pipe matrix. The zinc layer is thinner and simply adheres to the steel pipe substrate, which is easier to fall off and its corrosion resistance is poor. The Ministry of Construction has long since formally issued the following order to eliminate the technically outdated cold galvanized steel pipes, which are not allowed to be used as water and gas pipes. In new housing, the use of cold galvanized steel pipes as water pipes is also strictly prohibited.