Caracterização e avaliação das tensões residuais em juntas da liga de alumínio AA 5083-O soldadas pelo processo FSW.

Abstract

This study aims to evaluate the residual stresses and mechanical properties of Alumium - Magnesium AA5083-O welded joint using the Friction Stir Welding (FSW) process. Initially, twelve tool profiles with different pin geometries were fabricated in order to select the best profile for FSW welding. After that the welds were carried out by friction and mechanical mixing, adopting a 23 factorial experimental design with 3 central points to evaluate the influence of the welding parameters on the welded joint mechanical properties. To determine the residual stresses, a variation of the blind hole technique was performed using the coordinate table for measurements. For mechanical characterization, uniaxial traction, Vickers hardness and root folding at 60º test and optical microscopy were performed. Among the tool geometries studied, it was evident that the cylindrical threaded pin with rounded tip provided better mixing and better properties values. The FSW process with 3º tool inclination angle presented better results due to better mixing of the material. The best results in relation to mechanical resistance and residual stress level were obtained using 340 RPM and 180 mm/min and 70 mm/min of rotational and advance tool speed, respectively.