Roll crown control capacity of sextic CVC work roll curves in plate rolling process

Abstract

The shape curve of continuous variable crown (CVC) roll applied in plate rolling process is usually adopted as cubic curves or quintic curves, but the coupling between quadratic crown and quartic crown of conventional CVC roll shape curve could not work well and failed to meet the product quality requirements in plate rolling. To get better control effect on the composite wave shape, a sextic CVC roll shape curve was proposed. The theoretical calculation formula of the roll shape parameters was deduced by using the decomposition and superposition principle. Based on the actual production data of plate mill, sextic CVC work roll parameters were determined through the analysis of the convexity control ability of the curve. The application results showed that a sextic CVC roll shape curve can greatly improve the control ability of plate crown. The control ability of quadratic crown improved by 5% and that of quartic crown improved by 20%, respectively; further, the peak contact pressure of quintic CVC roll decreased from 2076 to 1744 MPa, and the difference between the maximum and the minimum of roll pressure was 184 MPa. The control ability of plate crown was controlled from − 67 to 63 μm with plate width equaling to 2400 mm. The deviation of measured value of plate crown and calculated value of plate crown was less than ± 4%.