Seamless steel pipe is a kind of hollow section, not peripheral joints of long steel. Hollow steel pipe with a large number of fluids used for pipeline transportation, such as transportation of oil, natural gas, gas, water and certain solid materials tunnels. Pipe and solid steel bar, etc., than bending same torsional strength, lighter weight, is an economic cross-section steel, widely used in the manufacture of structural and mechanical parts, such as oil drill pipe, automotive transmission, bicycle rack is used in construction and steel scaffolding. Pipe manufacturers annular parts, improve material utilization and the simplification of manufacturing processes, material savings and processing time, If Rolling Ring, Jack sets, and so on, has been widely used to manufacture pipe. Pipe or conventional weapons indispensable material, barrel, the barrel of a gun would have to manufacture pipe. Pipe shape by the different cross-sections can be divided into pipe and tube. As the perimeter of the same conditions, the largest area round, round tube can be used more transmission fluid. In addition, the ring-section, at the radial internal or external pressure, force more evenly, so that the overwhelming majority of tube pipe. However, the pipe has some limitations, such as by plane bending conditions, the better side on the tube, rectangular tube bending strength, some form of a framework, such as steel and wood furniture used on the side, the rectangular tube. According to different uses need to be other special-shaped cross-section shape of the pipe

Welded Pipe also said pipe, or using steel strip after curly after molding made of welded steel pipe. Welded Pipe simple production technology, production efficiency and product specifications, the equipment-less, but the general strength less than seamless steel pipe. During the 1930s, along with the production of high-quality strip rolling of the rapid development of the welding and inspection technology, Weld continually raising the quality of the welded pipe specifications growing varieties, and in an increasing number of fields instead of seamless steel pipe. By welding steel pipe weld in the form of Longitudinal and spiral welded pipe. Longitudinal simple production technology, high efficiency, low cost, rapid development. Spiral Welded Pipe Longitudinal intensity than the high they can narrow the billet production of larger diameter pipe, You may also use the same width of the billet production of different pipe diameters. But with the same length of straight pipe joints compared to the length of Weld 30 ~ 100%, but lower production rate. Therefore, the smaller diameter pipe used mostly straight seam welding and large-diameter pipe used mostly spiral welding