The non-uniform deformation of seamless steel tube becomes the residual stress after cold drawing under additional stress.Precision seamless steel tubes are widely used.General purpose seamless steel tubes are rolled from common carbon structural steels, low alloy structural steels or alloy structural steels to achieve the highest yield and are mainly used as conduits or structural parts for fluid delivery.Seamless steel pipe has a hollow section, a large number of fluid pipeline, such as the transportation of oil, natural gas, gas, water and some solid materials pipeline.Compared with round steel and other solid steel, steel pipe has the same bending and torsion strength and lighter weight. It is a kind of economic steel section.