Perm National Research Polytechnic University, Perm, Russia:
G. L. Kolmogorov, Professor of a Chair “Dynamics and strength of machines”, e-mail: dpm@pstu.ru
T. E. Melnikova, Assistant Professor of a Chair “Dynamics and strength of machines”

Metal forming, which purpose is product formation from simple metallic intermediates, is one of the main branches of industry. At the same time, coldrolling practice (including thin-strip rolling) is important. Problem solving, connected with the choice of optimal modes of thin-strip rolling, is urgent for the specialists in this area. External friction between the rolled strip and mill rolls is very important during the production of metal products with 0.10–0.05 mm thickness (for example, sheet metal ans non-ferrous foil). Rolling of such metal products is a specific process, because the contact stresses may several times exceed the deformation resistance of rolled metal. Modeling of friction conditions in deformation area is allowed by thin-strip rolling technology in hydrodynamic friction mode. Accounting of hydrodynamic effect of solid lubricant allows the assessment of influence of technological factors on contact friction during the metal forming and the control of rolling process. This work investigates the regularities of liquid newton lubricant flow taking into account the peculiarities of deformation zone geometry with thin-strip rolling. Regularities of formation of lubricant layer with thin-strip rolling were defined. As an example, there are shown the results of calculation of lubricant layer thickness during the rolling of aluminium foil using mineral oils with various viscosity as lubricant, depending on the rolling velocity. Assessment of the friction mode during rolling is offered according to the lubricant layer thickness: there was obtained the formula for assessment of the friction mode, which is defined by the ratio of lubricant layer thickness to the given parameter of rough edges of friction surfaces. Obtained ratios may be used in technological calculations of rolling process.

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