Cold drawn steel pipe is a kind of steel pipe, that is, it is classified according to different production processes, which is different from hot rolled (expanded) pipe. In the process of expanding the diameter of the blank or raw material pipe, it is processed by multiple passes of cold drawing, usually on a single-chain or double-chain cold drawing machine of 0.5 to 100T. Cold-rolled (dial) steel pipes are divided into general steel pipes, low and medium pressure boiler steel pipes, high pressure boiler steel pipes, alloy steel pipes, stainless steel pipes, petroleum cracking pipes, machined pipes, thick-walled pipes, small-diameter cold drawn pipes with internal molds, and other steel pipes , Also includes carbon thin-walled steel pipes, alloy thin-walled steel pipes, stainless thin-walled steel pipes, and special-shaped steel pipes. The outer diameter of cold drawn steel pipes can reach 6mm, the wall thickness can reach 0.25mm, and the outer diameter of thin-walled pipes can reach 5mm. The wall thickness is less than 0.25mm. The precision and surface quality are obviously better than those of hot rolled (expanded) pipes. Restrictions, its caliber and length are subject to certain restrictions.