Avaliação de tensões residuais e das propriedades mecânicas em juntas soldadas de ligas de alumínio dissimilares utilizando o processo FSW.

Abstract

The objective of this work was to evaluate the residual stress levels and the mechanical properties in dissimilar joints of the alloys AA 5083-O and AA 7075-T651 welded using the Friction Stir Welding (FSW) process. Initially, it was carried out the welding of the dissimilar joints of aluminum alloys using an Experimental Planning of the type 23 + 3 central points and then the evaluation of the influence of each welding parameter adopted on the mechanical properties through the software Statistica®. To determine the residual stresses, a variation of the blind hole technique was performed using, for measurements, the coordinate table. For mechanical characterization, it was performed visual inspection and uniaxial tension tests, Vickers hardness and bending test at 60º. Among the results of the visual inspection it was possible to notice that the welds occurred satisfactorily, without presenting any apparent defects. Regarding the mechanical properties, the welding parameter 2 (rotation speed: 350 RPM, travel speed: 180 mm/min and offset: 0 mm) obtained a higher limit value of tensile strength and maximum load. In terms of residual voltage, parameter 2 and parameter 3 (rotation speed: 870 RPM, travel speed: 40 mm/min and offset: 0 mm) provided adequate power inputs to reduce the residual stress levels.