Hot-dip galvanized steel pipe is widely used in construction, machinery, coal mine, chemical industry, electric power, railway vehicles, automobile industry, highways, Bridges, containers, sports facilities, agricultural machinery, petroleum machinery, prospecting machinery, greenhouse construction and other manufacturing industries. Galvanized steel pipe is a welded steel pipe with a hot dip plating or electric galvanized layer on the surface. Galvanizing can increase the corrosion resistance of the steel pipe and extend the service life. Galvanized pipe has a wide range of uses, in addition to the pipeline pipe for water, gas, oil and other general low pressure fluids, it is also used as the oil well pipe, oil pipeline, especially in the oil field of the petroleum industry, the oil heater, the condensing cooler of the chemical coking equipment, the tube for the coal distillation and washing oil exchanger, and the pipe for the trestle pipe pile and the support frame of the mine tunnel.