How thick is structural pipe?

Hot-rolled steel pipes have an outer diameter ranging from 32mm to 630mm and a wall thickness of 2.5mm to 75mm. Cold-drawn steel pipes, on the other hand, have an outer diameter ranging from 5mm to 200mm and a wall thickness of 2.5mm to 12mm.

Seamless steel pipes are divided into two categories: hot-rolled and cold-rolled (drawn) seamless steel pipes. Hot-rolled seamless 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, geological steel pipes and other steel pipes. Cold-rolled (drawn) seamless steel pipes include general steel pipes, low- and medium-pressure boiler steel pipes, high-pressure boiler steel pipes, alloy steel pipes, stainless steel pipes, petroleum cracking pipes and other steel pipes, as well as carbon thin-walled steel pipes, alloy thin-walled steel pipes, stainless thin-walled steel pipes and special-shaped steel pipes. The outer diameter of hot-rolled seamless pipes is generally greater than 32mm and the wall thickness is 2.5-75mm. The outer diameter of cold-rolled seamless steel pipes can reach 6mm and the wall thickness can reach 0.25mm. The outer diameter of thin-walled pipes can reach 5mm and the wall thickness is less than 0.25mm. Cold rolling has higher dimensional accuracy than hot rolling. Generally, seamless steel pipes are made of high-quality carbon steels such as 10.20.30.35.45, low-alloy structural steels such as 16Mn.5MnV, or alloy steels such as 40Cr.30CrMnSi.45Mn2.40MnB by hot rolling or cold rolling. Seamless pipes made of low-carbon steels such as 10.20 are mainly used for fluid delivery pipelines. Seamless pipes made of medium-carbon steels such as 45.40Cr are used to manufacture mechanical parts, such as the load-bearing parts of automobiles and tractors. Generally, seamless steel pipes must ensure strength and flattening tests. Hot-rolled steel pipes are delivered in hot-rolled or heat-treated states; cold-rolled steel pipes are delivered in hot-rolled or heat-treated states.