Two classifications of carbon steel pipes

Carbon steel pipes can be divided into hot rolled and cold rolled (drawn) two categories according to their production process.

There are many kinds of hot rolled carbon steel pipes, including general steel pipes, low and medium pressure boiler steel pipes, high pressure boiler steel pipes, alloy steel pipes, stainless steel pipes, petroleum cracking pipes, geological steel pipes and other special purpose steel pipes. These steel pipes in the production process, after high temperature heating, through the rolling process molding, has good mechanical properties and corrosion resistance.

The types of cold-rolled (dial) carbon steel pipe are also rich, in addition to including general steel pipe, low and medium pressure boiler steel pipe, high pressure boiler steel pipe, alloy steel pipe, stainless steel pipe, oil cracking pipe and other special purpose steel pipe, but also including carbon thin-wall steel pipe, alloy thin-wall steel pipe, stainless steel pipe and special-shaped steel pipe. These steel pipes are cold-rolled or drawn at lower temperatures and pressures during the production process, so they have better dimensional accuracy and surface finish.

The hot rolled seamless pipe is characterized by an outer diameter generally greater than 32mm and a wall thickness between 2.5-75mm. The outer diameter of cold-rolled seamless steel pipe can reach 6mm, and the wall thickness can reach 0.25mm. In addition, there are thin-walled tubes, whose outer diameter can be up to 5mm, and the wall thickness is less than 0.25mm. Because of the higher precision of the cold rolling process, the dimensional accuracy of cold rolling is higher than that of hot rolling.

General carbon steel pipe is made of 10, 20, 30, 35, 45 and other high-quality carbon junction steel, such as 16Mn, 5MnV and other low alloy structural steel, or 40Cr, 30CrMnSi, 45Mn2, 40MnB and other alloy steel hot rolled or cold rolled. Among them, seamless pipes made of low carbon steel such as 10 and 20 are mainly used for fluid transport pipelines. The seamless pipe made of 45, 40Cr and other medium carbon steel is often used to manufacture mechanical parts, such as the stressed parts of automobiles and tractors. When using carbon steel pipes, it is necessary to ensure that their strength and flattening tests meet the relevant standards. Hot-rolled steel pipes are usually delivered in hot-rolled or heat-treated condition; Cold rolling is delivered in heat-treated condition.