INFLUENCE OF REPAIR WELDING ON WELD QUALITY OF AL ALLOY EN AW 6082-T6

Article focuses on repair welding of precipitation hardenable Al alloy EN AW 6082-T6. During GMAW welding it occurs that welds need repair because of presence of unacceptable weld defects, such as cracks and porosity. These defects need to be removed and welded again to be repaired. Such repair welding procedure is believed to have detrimental influence on weld joint quality because of multiple heat cycle, especially if the repair welding is done repeatedly. To objectively estimate this influence, V joint butt welds of 10 mm thick sheet were done. Then weld has been removed by grinding and welded again. This process was repeated up to 4 times. After each repair weld, the weld quality was assessed by visual and penetration tests and by tests of mechanical properties. Theoretically expected premises that repeated heat input would lower every time mechanical properties have been proven. The most serious decline in properties is caused by first welding, further repair welds lower mechanical properties even more, but no so seriously. It can be concluded that repair welding is possible, but should be minimized. Results of the research were used to create WPS for repair welding of butt weld of EN AW 6082-T6.