Mixed-film lubrication theory and tension effects on metal rolling processes

A cold rolling model, based on Wilson and Chang's asperity flattering model and von Mises homogenous deformation model, for mixed film lubrication is developed A more rigorous average Reynolds equation is used to calculate th e hydrodynamic pressure. The variations of the yield stress with strain are considered in the model. An efficient iteration procedure is developed to solve the contact area, film thickness, and hydrodynamic pressure. The mode l is more practical with fewer assumptions, and converges quickly. It is ap plicable to a wider range of rolling regimes, particularly at high rolling speed. The calculation results agree well with the literature as well as wi th measured data from a rolling mill.