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

Ehsan Shafiei,Kamran Dehghani

doi:10.3390/jmmp2030048

Abstract

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.

Highlights

Environmental concerns, safety regulations, and consumer demands are driving the need for a lighter vehicle that is more fuel-efficient, produces lower emissions, and provides improved crash-worthiness and performance reliability [1]
It can be seen that the rolling force increases when downward rolling is performed; when downward rolling turns to flat rolling, the rolling force experiences a rapid drop
It is shown that the rolling force changes by a factor of two and six during variable gauge rolling (VGR) of the tailor rolled blanks (TRB) with thickness ratios of 0.89 and 0.47, respectively

Summary

Introduction

Environmental concerns, safety regulations, and consumer demands are driving the need for a lighter vehicle that is more fuel-efficient, produces lower emissions, and provides improved crash-worthiness and performance reliability [1]. Kopp et al [3] studied the forming behavior of TRBs made from DC04 steel utilizing deep drawing tests They found out that longer thickness transition zones (TTZs) result in less wrinkling. Liu et al [15] presented a kinematically admissible velocity field to analyze forward slip during different stages of variable gauge rolling. In both of these studies, the effects of friction coefficient, roll diameter and absolute thickness reduction on variations of rolling force during VGR were not studied. The main aim of this investigation is to study the effects of deformation conditions on the variations of rolling force during VGR of DP590.

Experimental Procedure

Results

Discussion

Conclusions