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

The present research aims to investigate the effects of Metal Inert Gas (MIG) weldingprocess on the mechanical properties and fatigue life of AA 6061 T6. A series ofexperimental 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 obtainmany butt welding joints with dimensions of (200 *100* 12) mm and with geometry ofsingle and double V at (70⁰) and square using ER- 5356 as a filler metal and argon asshielding gas. The welded pieces were tested by X-ray radiography and Faulty pieceswere excluded Welding joints were subjected to heat treatment including heating thejoints in furnace to (150 °C) for one hour then air cooling to relief heating stress.Allspecimens subjected to Vickers hardness, tensile test and microstructure examination.The examinations were carried out to show the effect of MIG weld method on the jointmicrostructure. The fatigue test of the welds and base alloy were examined to obtain theS-N curve.Results showed a general decay of mechanical properties of MIG weld jointthat is due to heat input during the welding process and low cooling rate