Abstract:
This study investigates the contact interaction between a thin composite strip and the rolls during rolling, focusing on conditions that ensure a horizontally straight exit end. The values of friction coefficients required to maintain a straight exit end during asymmetric rolling of a multilayer metallic material are determined. A finite element modeling of asymmetric rolling of a five-layer composite is performed with varying friction coefficients on rolls. The tool-workpiece interaction is modeled using the Amontons-Coulomb friction law, with the friction coefficient ranging from 0.1 to 0.4. The results show that a friction coefficient of 0.2 on both rolls minimizes the curvature of the exit end, resulting in an almost perfectly straight strip. For this optimal case, the stress-strain state is analyzed and the linear velocity distribution across the strip in the rolling direction is investigated. The analysis suggests that, upon passing across the deformation region, all material points move at a uniform velocity, which is significantly lower than the peripheral velocity of the lower roll, indicating persistent slip of the strip at the lower surface of the roll.
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