Seamless Steel pipes with hollow sections are widely used as conduits for conveying fluids, such as oil, natural gas, gas, water and some solid materials. Compared with solid steel such as round steel, steel pipe has the same bending and torsional strength and is lighter in weight. It is a kind of economic section steel, widely used in the manufacture of structural parts and mechanical parts, such as oil drill pipe, automobile transmission shaft, bicycle frame and steel scaffolding used in construction.