Development and Application of the Theory of Rigid Ends in Thin-Sheet Rolling

The article presents the results of an experimental study into the distribution of contact stresses (pressures) along the length of a milling roll barrel and external longitudinal stresses measured by a magnetic anisotropy sensor (MAD) with an accuracy of ±1 MPa over a width of 250 mm of a steel (08kp) strip with a thickness of about 1 mm during cold rolling at the exit from a four-roller mill 205/360 × 500. A quantitative analysis shows the influence of longitudinal stresses in the outer parts of the steel strip on the metal pressure in the deformation zone. An equation is proposed for calculating the coefficient of the influence of unevenness and distribution of longitudinal stresses along the strip width at the exit from the mill on the pressure of the metal on the rolls. A computer-aided design (CAD) system was used to model and calculate the deformation and strength indicators of rolling thin strips, taking into account the influence of the characteristics of the rigid ends on the deformation zone. The graphs of the distribution of normal and tangential stresses along the length of the deformation zone are calculated depending on the longitudinal stresses. I. M. Pavlov’s theory about the significant influence of the external “hard” parts of the strip on the pressure of the metal on the rolls is empirically demonstrated. Based on the results of the experiments, an equation is proposed that takes into account the effect of the uneven longitudinal stresses in the outer parts and the stiffness of the strip on the pressure. The equation for determining the average metal pressure on the rolls is refined, taking into account the influence of the outer parts of the strip on the deformation zone during thin-sheet rolling.