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Seamless steel hollow sections, widely used as pipeline fluids, such as transportation of oil, gas, gas, water and some solid materials, pipes and so on. Compared to other steel and solid steel bar, the same torsional strength in bending, lighter, is an economic cross-section steel, widely used in the manufacture structural parts and mechanical parts, such as drill pipe, automotive drive shafts, bicycle rack and construction using steel scaffolding with a steel pipe manufacturing annular parts, can improve material utilization, simplify the manufacturing process, saving materials and processing time, it has been widely used to make steel.