Welded steel tubes with hot dip or electrogalvanizing coating. Galvanizing can increase the corrosion resistance of steel pipe and prolong its service life. Galvanized pipe USES is very wide, in addition to a general low pressure fluid such as water, gas, oil line pipe, also used as oil industry, especially the ocean oil field oil well pipe, oil pipe, chemical coking equipment of oil heater, the condensing, exchange of coal distillation wash oil cooler for tube, and trestle pile, mining tunnel supporting frame tube, etc