In order to improve the corrosion resistance of steel pipes, general steel pipes are galvanized. Galvanized welded pipe is divided into hot galvanizing and cold galvanizing. Cold galvanizing is generally used less. Hot dip galvanized pipe is to make molten metal react with iron substrate to produce alloy layer, so that the substrate and coating can be combined. Hot galvanizing refers to pickling the steel pipe first. In order to remove iron oxide on the steel pipe surface, after pickling, the steel pipe is cleaned in ammonium chloride or zinc chloride aqueous solution or mixed ammonium chloride and zinc chloride aqueous solution tank, and then sent to the hot dip tank. Hot dip galvanizing has the advantages of even coating, strong adhesion and long service life.

Hot-dip galvanized steel pipes are widely used in the manufacturing industries of construction, machinery, coal mining, chemical industry, electric power, railway vehicles, automobile industry, highways, bridges, containers, sports facilities, agricultural machinery, petroleum machinery, prospecting machinery, shed construction, etc.
Galvanized steel pipe has a welded steel pipe with a hot dip or electro galvanized layer on the surface. Galvanization can increase the corrosion resistance of steel pipes and prolong the service life. Galvanized steel pipe has a wide range of uses, in addition to being used as a pipeline for general low pressure fluids such as water, gas and oil, it is also used as an oil well pipe and oil pipeline in the petroleum industry, especially in the marine oil fields, as an oil heater, condensation cooler and coal distillation and oil washing exchanger pipe for chemical coking equipment, and as a support frame pipe for trestle piles and mining pits, etc.