ABSTRACT
The automotive industry has been investing in new manufacturing processes that improve productivity without loss of quality. However, the presence of residual stress (RS), generated in all manufacturing processes, is one of the major problems encountered in the metalworking industry, since these can add up to external loading stresses and cause catastrophic failures in equipment and components. Since welding is one of the most widely used manufacturing processes, it is necessary to know how the welding parameters impact on the nature and magnitude of the residual stresses generated. The shielding gases are used in some welding processes and can be influence the conductivity of the electric arc, which can be affected the residual stresses behavior in the welded joints. In this work an experimental study was carried out about the influence of the percentage of CO2 on the argon-based shielding gases in the residual stresses generated on joints of high strength steel DP600 welded by GMAW process (widely used in the automotive industry). The residual stresses were measured by X-ray diffraction by the sin2ψ method. An assessment of the microstructural morphology by optical microscope (OM) was made. The results showed that the residual stresses have a tensile nature, of the order of 120 MPa, in all samples, which used shielding gas with a lower percentage of CO2.
Keywords
DP600 steel; GMAW; Residual stresses; Shielding gases; X-ray diffraction
