Influência do ângulo e do coeficiente de atrito nas tensões residuais geradas na trefilação de barras de aço AISI 1045

Wire Drawing is one of the most widely used metal forming processes in the manufacture of round steel bars and, of all, this process allows a high dimensional accuracy to the parts. To improve this process, it is necessary to know all the parameters and to identify their influence in the quality of the manufactured product. This study aims to evaluate the influence of friction and the die angle, by numerical simulation, in the residual stresses and distortions generated after heat treatment. Numerical simulations of the drawing process of round bars of AISI 1045 steel were carried out for a given diameter reduction aiming to evaluate the residual stresses in the center and on the surface of the bars. The simulations were performed considering an elastoplastic material from the Simufact.Forming- GP® database software, in which the die angle and the friction coefficient between the tool and the bars were varied. The validity of the simulations was evaluated by comparing the forces taken from simulation and the forces calculated by empirical equations found in the literature. The simulation results showed greater influence of friction and of the die angle in the residual stresses on the surface of the bar. In the center, the influence in the residual stresses is higher for small die angles. With the analysis of the comparison between the forces it may be assumed that the model has been reproduced correctly and that it can predict the force values of the process. Also, there was a greater influence of the die angle relative to the friction coefficient in the emergence of residual stresses. Key words: wire drawing, friction, die angle.