Theoretical analysis of minimum metal foil thickness achievable by asymmetric rolling with fixed identical roll diameters
(1. State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819, China;
2. Research Institute of Science and Technology, Northeastern University, Shenyang 110819, China;
3. School of Materials and Metallurgy, Northeastern University, Shenyang 110819, China)
2. Research Institute of Science and Technology, Northeastern University, Shenyang 110819, China;
3. School of Materials and Metallurgy, Northeastern University, Shenyang 110819, China)
Abstract: A novel approach is proposed for computing the minimum thickness of a metal foil that can be achieved by asymmetric rolling using rolls with identical diameter. This approach is based on simultaneously solving Tselikov equation for the rolling pressure and the modified Hitchcock equation for the roller flattening. To minimize the effect of the elastic deformation on the equal flow per second during the ultrathin foil rolling process, the law of conservation of mass was employed to compute the proportions of the forward slip, backward slip, and the cross shear zones in the contact arc, and then a formula was derived for computing the minimum thickness for asymmetric rolling. Experiment was conducted to find the foil minimum thickness for 304 steel by asymmetric rolling under the asymmetry ratios of 1.05, 1.15 and 1.30. The experimental results are in good agreement with the calculated ones. It was validated that the proposed formula can be used to calculate the foil minimum thickness under the asymmetric rolling condition.
Key words: minimum thickness; metal foil; law of mass conservation; asymmetric rolling