Dynamic rolling force modeling of cold rolling strip based on mixed lubrication friction.

The dynamic rolling force model in the coexistence regime of boundary lubrication friction and hydrodynamic lubrication friction was established in this paper, mainly aiming at the common mixed lubrication friction state in the actual rolling process, while the research of rolling mixed lubrication is relatively few. Combining Karman differential equation of unit pressure with Celikoff equation, a linearized differential equation of unit pressure was obtained. The expression of total friction stress under mixed lubrication state was given according to the oil film thickness at any position in the working area and the surface real contact area ratio. It is characterized by the consideration of the mixed lubrication friction state of the coexistence of boundary lubrication and hydrodynamic lubrication, which is applicable to the whole deformation zone and the general rolling mixed lubrication friction regime. The expressions of the unit normal pressure in the front-slip zone and the backward slip zone were obtained by considering the boundary conditions at the entry and exit cross sections. The dynamic rolling force model of cold rolling strip was established by numerical integral calculation. It is based on the above expression of total friction stress; therefore, this dynamic rolling force model is more universal, the prediction accuracy is higher, and it is closer to the actual industrial production. Based on the dynamic rolling force model, the effects of friction coefficient, reduction ratio, shear strength, and roll flattening on the unit normal pressure along the contact arc and the rolling force was also analyzed in this paper. Verification with actual industrial production data showed that the prediction model of rolling force had high precision, and it could provide guidance for calibration of rolling mill equipment and parameter optimization of production technology. [ABSTRACT FROM AUTHOR]