Seamless steel pipe is a hollow cross-section, not around the joints of long steel products. Hollow steel tube with a cross-section, a large number of fluids used for transmitting channels, such as the transportation of oil, natural gas, gas, water and some solid materials, such as pipeline . And so on solid round steel pipe and steel, the torsional bending strength with the same time, the light is an economic cross-section steel, widely used in the manufacture of structural and mechanical parts, such as drill pipe oil, automotive transmission shaft, Bicycle stand, as well as construction with steel scaffolding and so on. Ring with steel pipe manufacturing spare parts, improve material utilization, and simplify the manufacturing process, saving time and processing materials, such as the rolling bearing rings, jack sets, and so on, has been widely used to produce steel pipes . All kinds of steel pipe or conventional weapons, an essential material, barrel, the barrel must be such as to produce steel pipes. Pipe according to the shape of the cross-sectional area can be divided into different pipe and Yixing Guan. Circumference due to the same conditions, The largest area of a round, round tube can transport more fluid. In addition, the ring in the section under internal or external radial pressure, force more evenly, so the vast majority of steel pipe is the pipe. On the basis of seamless sensory Use the classification list is as follows: