Carbon steel tubes are made of ingot or solid round steel by perforation, and then hot rolled, cold rolled or cold drawn. Hot rolled carbon steel pipe is divided into general steel pipe, low and medium pressure boiler steel pipe, high pressure boiler steel pipe, alloy steel pipe, stainless steel pipe, petroleum cracking pipe, geological steel pipe and other steel pipe.
Cold rolled (drawn) carbon steel pipe is divided into general steel pipe, low and medium pressure boiler steel pipe, high pressure boiler steel pipe, alloy steel pipe, stainless steel pipe, petroleum cracking pipe, other steel pipes, but also includes carbon thin wall steel pipe, alloy thin wall steel pipe, stainless steel pipe, special-shaped steel pipe. The outer diameter of hot rolled seamless pipe is generally greater than 32mm, the wall thickness is 2.5-75mm, the outer diameter of cold rolled seamless steel pipe can be up to 6mm, the wall thickness can be up to 0.25mm, the outer diameter of thin-walled pipe can be up to 5mm, the wall thickness is less than 0.25mm, the cold rolling is higher than the hot rolling size accuracy.
General carbon steel pipe: it is made of 10, 20, 30, 35, 45 high quality carbon steel 16Mn, 5MnV and other low alloy structural steel or 40Cr, 30CrMnSi, 45Mn2, 40MnB and other alloy steel hot rolled or cold rolled. 10, 20 and other low carbon steel made of seamless pipe is mainly used for fluid conveying pipeline. 45, 40Cr and other medium carbon steel made of seamless pipe to manufacture machine parts, such as cars, tractors, force parts. Generally used carbon steel pipe to ensure the strength and flattening test. Hot rolled steel pipes are delivered in hot rolled or heat treated state; Cold rolling is delivered in heat treatment condition.