General seamless steel pipes are made of carbon structural steel, general high alloy steel, high quality alloy steel and alloy tool steel by hot rolling or cold drawing. Seamless steel pipes made of high carbon steel such as No.10 and No.20 are mainly used as gas transmission pipes for steam, liquefied gas, liquefied petroleum gas, gas, various crude oil commodities and various vapor or liquid; seamless steel pipes made of low carbon steel such as 45 and 40Cr are mainly used for manufacturing various equipment parts and pipe fittings.
