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.