Fluid conveying pipe is a hollow section, from the beginning to the end of weld. Fluid conveying pipe is hollow section, a large number of used for conveying fluid pipe of oil, gas, coal gas, water and some solid materials, such as pipelines.Fluid conveying pipe compared with the round steel and other solid steel, the bending torsional strength phase at the same time, the weight is lighter, is a kind of economic cross section steel, widely used in the manufacture of structural and mechanical parts, such as petroleum drill pipe, auto transmission shaft, bicycle frame and construction of steel scaffolding is used. With steel pipe manufacturing annular parts, can improve material utilization, simplifying the manufacturing process, material saving and processing time, such as rolling bearing ring, jack sets, etc., are now widely used fluid conveying pipe.