Approximate Model for Predicting Roll Force and Torque in Plate Rolling with Peening Effect Considered

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An approximate model for predicting roll force and torque in plate rolling is proposed. In this model, peening effect which unavoidably occurs in plate rolling due to a small ratio of work roll radius over mean thickness of slab (material) being deformed is considered. Besides, the proposed model does not need any iteration scheme to compute maximum reduction ratio per pass.The proposed roll force model consists of three parts: i) an ideal roll force under homogeneous deformation condition and ii) geometrical factor depending on inhomogeneous deformation state in roll gap and roll radius, material width and thickness and finally iii) the ratio of work roll radius increased by flattening over original roll radius. Multiplication of these three parts gives roll force in a given pass. A similar procedure was taken for roll torque model. A lever arm ratio which plays a vital role in computing roll torque was modified so that inhomogeneous deformation state of material in roll gap is fully covered.The validity of the proposed model is verified by applying it to No. 2 plate mill in POSCO. Results reveal that the predicted roll force and torque are in a good agreement with measured data, in comparison with conventional model being used. Accuracy of roll force is remarkably improved from 16.7 to 5.4% and that of roll torque is outstandingly enhanced from 26.0 to 6.3%.