Effects of Deformation Conditions on the Rolling Force during Variable Gauge Rolling

In this study, effects of different deformation conditions on the rolling force were studied during variable gauge rolling processes. To this end, variations of rolling forces with rolling times were analyzed at different roll diameters, absolute thickness reductions and friction coefficients. Considering the rolling force variations, an abrupt change in the outlet section of downward and outward rolling was observed at all deformation conditions. The experimental data, along with the results obtained from finite element method (FEM) simulations, revealed that this drop in the rolling force (DRF) is strongly dependent on the deformation conditions. It was found that the DRF value increases with increasing absolute thickness reduction, roll diameter and friction coefficient. Furthermore, dependency of contact length on the roll radius and wedge angle (slope of the thickness transition zone) was investigated. Accordingly, it was concluded that the variations of the DRF value can be mainly attributed to the changes in the contact length during variable gauge rolling. Moreover, slab method analysis was used to model the effects of deformation conditions on DRF.

From TRB and LP Plate to Variable Gauge Rolling: Technology, Theory, Simulation and Experiment

Tailor Rolled Blank (TRB) and Longitudinal Profile plate (LP plate) are both new products for materials saving. TRB produced by cold rolling can partially substitute for Tailor Welded Blank (TWB) achieving lightweight in vehicles. LP plate produced by hot rolling can be utilized in shipbuilding, bridge manufacturing and constructions, realizing structures lightweight. This paper stressed the common point of TRB and LP plate: Variable Gauge Rolling (VGR). Basic equations of VGR were deduced, a velocity relationship which assures the shape and dimension of transition region was provided, a FEM simulation of VGR was performed, VGR experiments were carried out and TRB samples with a thickness ratio 1:2 were obtained. All above achievements have established a foundation for VGR’s industrial application.

Research on Roll Force for Variable Gauge Rolling

The production of materials saving products such as Longitude Profile plates (LP plate) and Tailor Rolled Blanks (TRB) needs to solve the problem of the calculation of variable gauge rolling (VGR) parameters. It has been proved that Karman differential equation of force equilibrium for simple rolling is a special case of VGR equations when vy＝0. Differential equations of force equilibrium for both upwards rolling and downwards rolling were solved and the rolling pressure distribution function for VGR was got in this paper. Finally, details of a set of experiments were presented and the theoretical model of rolling force was proved to be reasonable.