Seamless steel pipe is hot-rolled, while seamless steel pipe is cold drawn The production process of seamless steel pipe: The seamless steel pipe is mainly completed by tension reduction. The tension reduction process is a continuous rolling process of hollow base material without a mandrel. Under the premise of ensuring the welding quality of the main pipe, the welding pipe tension reducing process is to heat the welded pipe as a whole to above 950 degrees Celsius, and then roll it into various outer diameters and walls by a tension reducer (the tension reducer has 24 passes) For thick finished pipes, the hot rolled steel pipes produced by this process are essentially different from ordinary high-frequency welded pipes. After being heated by the heating furnace, the autobiographic structure and mechanical properties of the weld and the parent body can be completely consistent. Besides, through multiple passes, The secondary tension reducer rolling and automatic control makes the dimensional accuracy of the steel pipe (especially the roundness and wall thickness accuracy of the pipe body) better than similar seamless pipes. Fluid pipes produced in developed countries in the world have adopted a large number of welded pipe seamless technology in boiler pipes. With the development of society, domestic hot rolled welded pipes have gradually replaced seamless pipes. 

The difference between the seamless steel pipe and seamless steel pipe can be seen from several aspects: 
1. Welded pipes are generally fixed-length, and are generally 6 meters, 9 meters, or 12 meters. There are very few seamless steel pipes with fixed-length because the fixed-length ex-factory price increases very much. 
2. It can be seen from the cross-section of the pipe head. If there is rust, wipe it cleans. If you look closely, you will find the welding area.
3. It will be most obvious if it is pickled.