Precision steel tubes is a means of cold drawn or hot-rolling process of steel materials with high precision. Because precision steel inner and outer walls no oxidation layer, under high pressure without leakage, high precision and smoothness, cold bending deformation, flaring, flattening without cracking a little, mainly for the production of pneumatic or hydraulic components of the product, such as a cylinder or cylinder. Stainless steel tube is a hollow circular steel strips, which are widely used in petroleum, chemical, medical, food, light industry, mechanical devices and other industrial pipeline and mechanical components. In addition, bending, torsional strength is the same as light in weight, it is also widely used in the manufacture of mechanical components and structures. Also used in producing a variety of conventional arms, barrel, shells, etc. Shaped seamless steel tube is except round tube yiwai of other section shape of seamless steel tube of General, by pipe section shape size of different and can is divided into, wall thick shaped seamless steel tube (code for d), and ranging wall thick shaped seamless steel tube (code for BD), and variable diameter shaped seamless steel tube (code for BJ), shaped seamless steel tube widely for various structure pieces, and tool and mechanical parts, and round tube compared, shaped tube General are has larger of inertia moment and section module, has larger of anti-bent anti-twist capacity.