According to the deformation characteristics of three-roll tube rolling,the existent disadvantages of tradi- tional A Geleiyi and A Tselikov's formulas were objectively analyzed.An assumption approximate to actual situation was put forward. After suitable simplification, the energy method was adopted to establish velocity fields for permis- sive movement in deformed areas, and the calculation formula of average unit pressure for three-roll tube rolling was deduced. The values of theoretical calculation are basically consistent with the measured values of large-scale alumi- num tube during on-site rolling process.The results proved that the formula is reasonable.
