Tube shrinkage is a forming process to reduce the diameter of the end of the tube billet. The tube blank enters the deformation zone under the action of axial force, generates the plastic deformation of tangential shrinkage in the deformation zone, and then enters the stability zone, and finally forms the reduced end diameter.

Pipe flaring is a forming process in which the end diameter of the tube billet is enlarged. The flaring shape can be conical or tubular. The tube billet enters the deformation zone under the action of axial force, and the plastic deformation of the tube billet with tangential stretching is generated in the deformation zone.