Investigation of fatigue life of 6061-T6 aluminum alloys welded by metal inert gas welding

Abstract

The present research aims to investigate the effects of Metal Inert Gas (MIG) welding process on the mechanical properties and fatigue life of AA 6061 T6. A series of experimental techniques has been conducted to evaluate the mechanical and fatigue life. metal inert gas (MIG) have been carried out on Rolled sheet of 12mm thickness to obtain many butt welding joints with dimensions of (200 *100* 12) mm and with geometry of single and double V at (70⁰) and square using ER- 5356 as a filler metal and argon as shielding gas. The welded pieces were tested by X-ray radiography and Faulty pieces were excluded Welding joints were subjected to heat treatment including heating the joints in furnace to (150 °C) for one hour then air cooling to relief heating stress.All specimens subjected to Vickers hardness, tensile test and microstructure examination. The examinations were carried out to show the effect of MIG weld method on the joint microstructure. The fatigue test of the welds and base alloy were examined to obtain the S-N curve.Results showed a general decay of mechanical properties of MIG weld joint that is due to heat input during the welding process and low cooling rate.