ВПЛИВ СХЕМИ НАВАНТАЖЕННЯ НА ПРОЦЕС ГНУТТЯ З РОЗТЯГАННЯМ
The paper considers the bending processes with additional load at a sequential loading. The research of the dependence of plasticity on the scheme of the stressed state was analyzed. The estimation of the bending efficiency was made without calculation of the stressed-deformed state of a work piece. According to the balance conditions of the work piece element, it was obtained the equation expressing dependence of thickness of the work piece in its different sections on its bending force fluctuation, thickness limits and the friction coefficient. In the paper, the authors have presented results of industrial experiments for the coaches carline radial-draw forming at their bending and tensile with bending. It was determined the influence of the loading diagram during the bending, drawing and forming processes onto the wall thickness variation of the work pieces produced. Minimum of the wall thickness variation at radial-draw forming occurs when the tensile stress compensates the friction forces action. At radial-draw forming and stamping the coefficient of friction between the punch and the blank is determined by the change of the thickness of the blank.