A comparison between macroshear redundancy and loading effects in 2- and 3-roll rotary tube cone piercers

Abstract Very high levels of redundant macroshear strains generated in the oblique rotary-piercing processes are detrimental to the quality of the blooms produced. Although the situation is improved when cone-type rolls are used, the question of the choice of the particular piercing system still remains. In this paper, using lead and internally-marked wax billets, an experimental comparison is drawn between the redundant-macroshear effects, and also between the force parameters in 2- and 3-roll tube cone rotary piercers. The optimal rolling conditions are indicated, and the respective advantages and disadvantages of the two systems are discussed.