Three-dimensional numerical analysis of the rotary piercing process was performed by the rig d plastic finite element method. Rotary piercing, also known as the Mannesmann piercing process, is a hot rolling process that manufactures seamless tubes. In this process, the heated round billet is rotated by the rolls and pierced by the plug as an internal tool. Numerical analysis was conducted to investigate the deformation behaviour during rotary piercing and redundant shear deformation specific to this process. This paper discusses the effect of various rolling parameters on redundant shear deformation.