Alloy pipe is hollow section, a large number of pipeline used for conveying fluid, such as oil, natural gas, coal gas, water and some solid materials, such as pipelines. Compared to the alloy steel pipe and round steel solid steel bending torsional strength phase at the same time, the weight is lighter, the alloy steel pipe is a kind of economic cross section steel, widely used in the manufacture of structural and mechanical parts, such as petroleum drill pipe, auto transmission shaft, bicycle frame and construction of steel scaffolding is used. Alloy steel pipe manufacturing annular parts, can improve material utilization, simplifying the manufacturing process, material saving and processing time, such as rolling bearing ring, jack sets, etc., the current has been widely made from steel pipe. Alloy steel pipe is indispensable to all kinds of conventional weapons material, gun, gun barrel to steel pipe manufacturing. Alloy steel pipe according to the cross-sectional area in the shape of different can be divided into circular tube and special pipe. Due to the equal conditions, the circumference circle area is the largest, with circular tube can deliver more fluid