SOME CONSIDERATIONS ABOUT THE WELDABILITY OF THE AA 5186 ALUMINUM ALLOY BY GMAW PROCESS

Abstract

The aluminum alloys of the 5XXX series present a high weldability. However, at the present time, several proposals have been proposed for improving the behavior of these joints. These proposals are based on on either specific chemical contents of the alloy elements or mechanical works on the weld beads. Moreover, industrial welding processes are carried out selecting operating parameters that sometimes have not been experimented sufficiently before. In this research paper GMAW welded joints of AA 5186 aluminum alloy have been researched. The influence of current, welding speed and shielding gas flow on the appearing porosity and on metallurgical segregation. The range of the values selected for the welding parameters have been taken from the industrial experience and with total penetration tests. It has been experimented with a heat input values from 325 to 830 kJ/m, with gas flows from 2 to 26 l/min and with welding speeds from 25 to 100 cm/min. The influence of gas nature has been also considered and tests have run with argon and argon-helium mix. Results demonstrated that shielding gas flow must be similar for the root and the heat of the bead. Welding speed allows control the microstructure that is obtained in the joint. High velocities lead to achieve uniform and non segregated metallurgical structures.