Practice of O.D.-reduction Piercing Process

Three different piercing processes are described.With case analyses, the O.D.-reduction piercing processes with barrel roll piercer or cone type piercer are investigated.Based on relevant theories, problems concerning the piercing operations are analyzed, and countermeasures are determined.The operation practice shows that the precondition for O.D.-reduction piercing operation is forward-shifting of the deformation zone, and that O.D.-reduction piercing with barrel roll mill is easier than that with cone type mill, and that the tool consumption and mill load for O.D.-reduction piercing is higher than those for O.D.-expansion piercing.