Cold rolled (dial) carbon steel pipe in addition to general low and medium pressure boiler steel pipe high pressure boiler steel pipe alloy st eel pipe stainless steel pipe petroleum cracking pipe other steel pipe, also including carbon thin-wall steel pipe alloy thin-wall stainless steel pipe stainless steel pipe special-shaped hot rolled seamless pipe outer diameter is generally greater than 32mm, wall thickness 2.5-75mm, cold rolled seamless steel tube outer diameter can be 6mm, wall thickness can be 0.25mm, thin wall tube outer diameter can be 5mm, wall thickness is less than 0.25mm, cold rolling than hot rolling dimensional accuracy is high.