Asymmetric hydrodynamic roll gap model and its experimental validation

Abstract

In tandem hot strip rolling mills, different friction between the rolls and the strip material on the upper and lower strip surface can occur due to asymmetric surface temperatures or different conditions of oil lubrication. To capture these effects, this paper presents a hydrodynamic roll gap model with asymmetric friction. Based on similarities between the rolled material and viscous fluids, fluid mechanics theory is used to derive this model. Due to the nature of this model, the influence of the rolling speed is inherently taken into account, which allows an accurate prediction of the rolling force and the forward slip. As an analytic solution for the hydrodynamic roll gap model is available, it is well suited for online applications in rolling plants. For validation of the proposed model, an experiment with asymmetric work roll roughness was performed. A specimen of steel strip with copper pins inserted was repeatedly rolled to visualize the material flow inside the roll gap for multiple passes. The resulting deformed copper pins were cut out of the strip and show good agreement with the deformation profiles calculated by the developed model.

Mechanism of and Key Technologies for Copper Bonding in the Hot Rolling of SCR Continuous Casting and Rolling

“…Based on our research regarding the copper sticking behavior of rollers, we propose that the problem of copper sticking can be improved by adjusting the roller speeds and gap size employed in this process. A prior study [40] simulated the deformation law of copper during the rolling process by establishing a hydrodynamic roll gap model of asymmetric friction conditions during copper hot rolling and its analytical solution, and clarified that the roll gap has an important effect on the plastic deformation of hot rolled copper. The poor rolling condition of the 2# stand copper rod in and out rolling was solved by considering the mechanism of copper sticking.…”

Application of Machine Learning Methods for the Prediction of Roll Force and Torque during Plate Rolling of Micro-alloyed Steel

“…In one of the work, a hydrodynamic roll gap model with separate friction coefficients for the upper and lower strip-roll contact surface has been proposed for prediction of roll force and deformation profile and which can be analytically solved and thus can be used for online applications in strip rolling. However, the results are validated with experimental data only [ 18] .Finite Element Method (FEM) has also been extensively used to study the complex rolling process [19]. However, FEM is not suitable for on-line adaptation due to the requirement of huge computation times and memory capacities.…”