Hydrodynamic effect of technological lubrication and friction modes formation at sheet rolling

One of the main engineering industries is the processing of metals by pressure. Its purpose is the formation of products from metal blanks of simple forms. An important role in this case belongs to the technology of sheet rolling. The solution of issues related to the choice of optimal modes of sheet rolling is relevant for specialists in the field under consideration. The process of rolling metal products is special, since the contact stresses can exceed the deformation resistance of rolled metal by several times. The tasks of predicting the quality of products, taking into account the prevention of sheet metal continuity defects, as well as the study of technological operations reliability of rolling process are associated with the solution of industrial and scientific problems in this area. Domestic and foreign researchers have noted a significant influence of external friction in the deformation center on the technological parameters of rolling process and quality of the resulting metal products. It is known that rolling is impossible without external friction between metal and roll. The reduction of friction provides an opportunity to increase the economic indicators of sheet rolling, and the rolling production technology itself has significant opportunities for further improvement. Technology of sheet rolling in the conditions of hydrodynamic friction mode allows modeling of friction conditions in the deformation zone. Taking into account the hydrodynamic effect of lubrication allows us to assess the influence of technological factors on the conditions of contact friction during metal pressure treatment and to control the rolling process. Regularities of the flow of liquid Newtonian lubricant are investigated, taking into account features of the deformation zone geometry during sheet rolling. Pumping capacity of the lubricating wedge during rolling is determined, which allows us to explain the regularities of lubrication influence on friction conditions. As an example, the results of calculation of the lubricant pressure depending on the rolling speed are presented. The rolling speeds that provide a liquid friction mode are given. The obtained relations allow us to estimate the influence of contact friction on technological parameters of sheet rolling and can be used in technological calculations of this process

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