Cold Expanding

After welding, the roundness and straightness of the pipe often can not meet the relevant standards and technical requirements. The pipe factory adopts sizing and fixed straightness to complete the process by mechanical cold expansion.

The final step of hot deformation is to determine the pipe size and reduce the production of hot-rolled seamless steel pipe. Its main function is to improve the outer diameter accuracy and roundness of the finished hot-rolled pipe because the outer diameter of the process changes due to the elimination of changes in the rolling process. Pipe sizing, reduction rolling by pressing and drawing are hollow processes without mandrel. At present, the advanced setting value (negative value) in China is used in the bisection sample of three high rolling mill with 120 ° roll. This type of setting value (negative value) is obtained after good surface quality of rolling pipe and specification of finished pipe