Carbon steel seamless steel pipe and round steel and other solid steel, in the bending and torsional strength of the same weight is lighter, is a kind of economic section of steel, widely used in the manufacture of structural parts and mechanical parts, such as oil drill pipe, automobile drive shaft, bicycle frame and construction used in steel scaffolding. This standard is applicable to the chemical composition, mechanical properties, test methods, inspection rules, dimensions and weight of the carbon steel seamless steel tubes used for grade 2 and grade 3 equipment of the second generation plus nuclear power stations of M310 type. Widely used in construction, chemical, food, agriculture, ship parts and other industries.Suitable for train, airplane, conveyer belt, vehicle, bolt, nut, spring, screen, etc.