Simulação numérica das deformações e tensões residuais na fabricação de um componente soldado

Abstract

In the metal industry, welding processes are an essential part of the manufacturing process, and in some cases the key factor of success. In the railcars segment, distortions and residual stresses due to the welding process can impact the manufacturing assembling, operation and service life of the equipment, causing undesirable costs of repair and warranty. Due to the complexity of the welding process, normally empirical knowledge is used to pre-study the effect of the distortions. Based on this scenario, this thesis aims to study the distortions and residual stresses generated by the welding process using the finite element method. The part of study in this work was a railcar component, made of Usiminas structural steel class USI SAC-350 and featuring axial and transverse ribbing welded by FCAW process. This piece demands a strict geometric tolerance, which makes important this study for this application. To carry out the simulations, the software Simufact Welding® version 4.0.1 was used, provided by Simufact Americas LCC. In order to evaluate the influence of the welding sequence and parameters, and the size of fillet weld on the development of distortions, three different conditions were simulated modifying these parameters and the results were validated with experimental data. The manufacturing and inspection of the models were performed using resources provided by the company Usiminas Mecânica S/A, located in Ipatinga, Minas Gerais. The numerical results were partially consistent with the experimental data, showing that the methodology used can be a viable tool to predict distortions caused by the welding process.