Welded steel pipe with hot dip or galvanized layer on the surface of galvanized steel pipe. Galvanizing can increase the corrosion resistance of steel pipe and prolong its service life. Galvanized pipes are widely used not only as pipelines for general low-pressure fluids such as water, gas and oil, but also for oil wells and pipelines in petroleum industry, especially in offshore oilfields, oil heaters, condensers and coolers for chemical coking equipment, pipes for coal distillate wash oil exchangers, and supports for Trestle pipe piles and mine tunnels. Wait a minute.