Effects of Arc Welding Current on the Mechanical Properties of Aluminium Plate Weldments

This study presents the effect of arc welding current on the mechanical properties and microstructure of the welded aluminium plates. The welded samples were prepared for tensile test, microstructural analysis, microhardness and XRF analysis. The tensile test results recorded a maximum UTS value of 88.333 MPa in sample E welded at a current of 90 A while sample A welded at a current of 50 A exhibited the lowest UTS of 33.70 MPa. Sample E produced a fine structure with fine dendrites. The tertiary dendrite grains showed a good sign of high strength when compared to the primary and coarse dendrite grains that were formed in sample A, welded at 50 A. The hardness values were presented and decreased as the welding current was increased from sample B to sample D and later increased in sample E, which could be as a result of the cooling rate at high heat input.