Seamless steel pipe is divided into two categories, including hot-rolled and cold-rolled seamless steel pipe.
Hot-rolled seamless steel pipe contains general steel pipe, low and medium pressure boiler steel pipe, high pressure boiler steel pipe, alloy steel pipe, stainless steel pipe, oil cracking pipe, geological pipe and other steel pipe.
In addition to the general steel pipe, cold-rolled seamless steel pipe also contains low pressure boiler steel pipe, high pressure boiler steel pipe, alloy steel pipe, stainless steel pipe, oil cracking pipe, other steel pipe, but also include carbon thin-walled steel pipe, alloy thin-walled steel pipe, stainless steel pipe, special-shaped steel tube.
The diameter of hot-rolled seamless pipe is generally greater than 32mm, wall thickness is 2.5-75mm, the diameter of cold-rolled seamless steel pipe can be 6mm, wall thickness can be 0.25mm, the diameter of thin tube can be 5mm, wall thickness is less than 0.25mm, Cold-rolled seamless steel pipe has higher dimensional accuracy than the hot-rolled seamless steel pipe.
The seamless steel pipe for general use: is made by 10,20,30,35,45 and other high-quality carbon steel, 16Mn, 5MnV and other low-alloy structural steel or 40Cr, 30CrMnSi, 45Mn2, 40MnB alloy steel by hot-rolled or cold rolled. The seamless steel pipe made by 10,20 and other low-carbon steel is mainly used for fluid transportation pipeline. The seamless steel pipe made by 45,40Cr and other carbon steel is mainly used to manufacture mechanical parts, such as cars, tractors force parts. The seamless steel pipe for general use should ensure strength and flattening test. The hot-rolled steel pipe is delivered in a hot-rolled state or a heat-treated state, cold-rolled steel is delivered in a heat-treated state.