A numerical approach to determine flow stress–strain curve of strip and friction coefficient in actual cold rolling mill

An inverse scheme-based approach for the prediction of flow stress–strain curve and friction coefficient using actual mill data is presented. The equations for roll force and forward slip are selected as the basic ones. Then they are inverted such that the deformation resistance and friction coefficient can be expressed as a function of process parameters measurable during rolling such as strip width, entrance and delivery thickness, forward and backward tensile stress, forward slip, roll force and roll diameter. A procedure for solving the inverse equations is described in detail. It includes steps which solve non-linear equation and generate the flow stress–strain curve from the data set of deformation resistances using the least square method. The capability of the present approach is verified by applying it to a reversible cold rolling mill. A good agreement is noted between the predicted flow stress–strain curve and the measured one.