Seamless steel tube with a hollow section, no juncture of strip steel around. Steel has hollow section, a large number of transmission fluid as shuh as petroleum, natural gas, coal gas, water and some solid materials etc.
Hot-rolled steel tube and solid steel, etc. In the flexural strength of resistance to twist, the weight is light, it is a kind of economic section steel, are widely used in the manufacturing of structural and mechanical parts, such as oil pipe, auto transmission shaft, bicycle racks and construction of steel scaffolding, etc.
Use steel pipe manufacturing annular parts, can improve the simplified manufacturing processes, materials, saving material and processing, such as rolling bearing collar, jack sets etc, has been widely used the pipes

1. the tensile strength , the yield point.so elongation.hardness index  is best