Seamless Steel Pipe Categories: Seamless steel pipes are divided into three types: hot-rolled, cold-rolled, and cold drawn seamless pipes. Hot-rolled seamless pipes include general steel pipes, low and medium-pressure boiler pipes, high-pressure boiler pipes, alloy steel pipes, stainless steel pipes, petroleum cracking pipes, geological pipes, and other steel pipes.

Cold-rolled seamless steel pipes, in addition to general steel pipes, low and medium pressure boiler pipes, high-pressure boiler pipes, alloy steel pipes, stainless steel pipes, petroleum cracking pipes, and other steel pipes, also include carbon thin-walled steel pipes, alloy thin-walled steel pipes, stainless thin-walled steel pipes, and special-shaped steel pipes. Hot-rolled seamless pipes typically have an outer diameter greater than 32mm and wall thickness of 2.5-75mm. Cold-rolled seamless steel pipes can have an outer diameter down to 6mm and a wall thickness down to 0.25mm, with thin-walled pipes having an outer diameter down to 5mm and a wall thickness less than 0.25mm. Cold-rolled pipes offer higher dimensional accuracy than hot-rolled pipes, and cold drawn seamless steel pipes

General Seamless Steel Pipes: These are hot-rolled or cold-rolled from carbon structural steels such as 10#, 20#, 30#, 35#, 45#, 16Mn, 5MnV, and low-alloy structural steels such as 40Cr, 30CrMnSi, 45Mn2, 40MnB, etc. Seamless pipes made from low-carbon steels like 10# and 20# are mainly used for fluid conveyance pipelines. Seamless pipes made from medium-carbon steels such as 45# and 40Cr are used to manufacture mechanical parts, such as load-bearing parts for cars and tractors. Seamless steel pipes generally need to ensure strength and flattening tests. Hot-rolled pipes are delivered in a hot-rolled or heat-treated condition; cold-rolled pipes are delivered in a heat-treated condition.