After completion of welding, pipe roundness and straightness often can not meet the relevant standards and technical requirements, sizing and fixed straightness is used pipe plant, cold bulged by mechanical methods to complete.
Pipe sizing and reducing production of hot-rolled seamless steel pipe shortage in the last step of thermal deformation, its main role is the outer diameter of the procedure due to the elimination of the rolling process before varying, in order to improve the hot-rolled finished tube outer diameter accuracy and roundness. Pipe sizing, reducing and stretch reducing rolling process is a hollow body process without mandrel. The current domestic advanced set (minus) are used in a three-roll mill aliquots of 120 ° roll, using this type of set (minus) after good mill pipe surface quality and specifications of finished pipe more.
