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 pipes.
In addition to general steel pipe, low and medium pressure boiler steel pipe, high pressure boiler steel pipe, alloy steel pipe, stainless steel pipe, petroleum cracking pipe and other steel pipes, cold rolled (drawn) carbon steel pipe also includes carbon thin-wall steel pipe, alloy thin-wall steel pipe, stainless thin-wall steel pipe and special-shaped steel pipe.
The outer diameter of hot-rolled seamless pipe is generally greater than 32mm and the wall thickness is 2.5-75mm. The outer diameter of cold-rolled seamless pipe can be up to 6mm and the wall thickness can be up to 0.25mm. The outer diameter of thin-walled pipe can be up to 5mm and the wall thickness is less than 0.25mm. Cold rolling has higher dimensional accuracy than hot rolling.
General carbon steel pipe: it is made of high-quality carbon steel such as 10, 20, 30, 35 and 45, low-alloy structural steel such as 16Mn and 5mnv, or alloy steel such as 40Cr, 30CrMnSi, 45Mn2 and 40MnB. 10. Seamless pipes made of low carbon steel such as 20 are mainly used for fluid transmission pipelines.
Seamless pipes made of medium carbon steel such as 45 and 40Cr are used to manufacture mechanical parts, such as stressed parts of automobiles and tractors.
Generally, the strength and flattening test of carbon steel pipe shall be ensured. Hot rolled steel pipes shall be delivered in hot rolling state or heat treatment state; Cold rolling is delivered in heat treated condition.

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