Seamless steel pipe has a hollow section. A large number of seamless steel pipe are used for conveying fluid materials and some other solid materials. etc. Seamless steel pipe is a kind of economical material, which is widely used in manufacture oil tube and mechanical parts. The application of seamless steel pipe can bring such advantages:

1) Improving the utilization of materials

2) Simplifying the manufacturing process

3) Saving materials and processing time. 

There are two types of seamless steel pipe according to the different manufacturing process of seamless steel pipe.

Hot rolled seamless pipe

Relatively speaking, the criterion we used to distinguish cold rolling and hot rolling is that cold rolling method is carried on rolling below the temperature of recrystallization, while hot rolling is above the recrystallization temperature. Hot rolled seamless steel pipe can be generally divided into low, medium, high-pressure boiler steel pipe, alloy steel pipe, stainless steel pipe, oil cracking pipe, geological steel pipe, and other steel pipes. The outside diameter of the hot-rolled seamless tube is generally greater than 32mm and the wall thickness of that is 2.5-75mm.

Cold rolled seamless pipe

Cold rolled seamless tube is a seamless steel tube for high dimensional accuracy and good surface finish. Cold rolled seamless pipe not only includes the general steel, low and medium pressure boiler tube, high-pressure boiler tubes, alloy steel pipe, stainless steel pipe, and oil cracking tube but also includes steel pipes featured with carbon thin wall, alloy thin wall, thin-walled stainless and special-shaped. The diameter of cold rolled seamless steel pipe is 6mm, the wall thickness is 0.25mm, while the diameter of the thin-walled tube can be 5mm, the wall thickness can less than 0.25mm. The dimensional accuracy of cold rolling is higher than that of hot rolling.

What’s the difference between the hot rolled seamless steel pipe and cold rolled seamless steel pipe?

The main difference between the hot and cold rolling seamless pipe:

1. Cold rolled/drawing steel pipes' sections allow local buckling, which can make full use of bar buckling bearing capacity. While hot rolled steel pipe does not allow the local buckling of the cross-section.

2. The reasons for the residual stress of hot rolled and cold rolled steel pipe are different. So the distribution of the cross section is also very different. The residual cold-rolled steel section stress distribution is curved, and hot rolled steel or steel welding section on the residual stress distribution is thin.

3. The free torsion rigidity of hot-rolled steel is higher than that of cold rolled steel.