Research on nonlocal contact stress at deformation zone in lubricated cold strip rolling

In order to accurately obtain the distribution of contact stress at deformation zone, a nonlocal stress gradient model derived from the combination of lubrication theory and nonlocal theory has been developed to research the nonlocal contact stress of full film lubrication in cold strip rolling. According to the characteristic of rolling lubrication at whole deformation zone, the mathematical expressions of nonlocal contact stress are derived in inlet zone, plastic deformation zone, and outlet zone, respectively. Then, the accuracy of results predicted by proposed nonlocal model are verified by experimental data. Meanwhile, the effect of the characteristic parameter on the stress difference which characterizes the nonlocal effect in three zones are discussed. It can be found that the nonlocal effect is most obvious in the inlet zone and weakest in the plastic deformation zone. The research results of this work are helpful to improve the calculation accuracy of contact stress in lubricating rolling, which has practical application value for producing high quality strip.