Analytical calculation of sheet curvature in four-roll mills at tubes production

Abstract

Stationary bending of sheet metal on the electromechanical rolling mills demonstrates high productivity and efficiency, relevant for any modern enterprise. Regardless of the number of shafts, the operating principle of the mills is not complicated. The sheet blank is installed in the gap between the shafts, which rotate in different directions. Passing between the cylinders, the sheet bends and takes the desired shape. The main assortment of finished products, produced with the help of rollers, are details in the form of a cylinder, cone or oval. The cold bending method, which is the basis of the working process, does not destroy the metal and does not have a negative influence on its structure, as it sometimes happens during prolonged thermal exposure on metal alloys. The popularity of roller mills is largely due to their relatively low cost, as well as minimal outlay on maintenance and exploitation. If the company needs a cheaper and more economical mills, it is worth paying attention to manual models. For larger companies, the four-roller mills equipped with CNC-systems and operating in automatic regime are recommended. Modern models, produced by leading manufacturers, are favorably distinguished by visibility and ease of exploita-tion, attractive design, guaranteed safety and reliability. Such equipment is in demand in mass production, where high productivity and trouble-free operation of mills are appreciated. It is impossible to guess the sheet blank curvature in rolling new type of tube. This paper is devoted to the solution of this important problem and to analytical calculation of blank curvature in the four-roller mills.