Laser welding of A357 aluminium alloy

Abstract

Welding of aluminium alloys poses many problems like porosities, lost of alloying elements, bead geometry and softening of heat affected zone. Laser welding is widely used in industrial production owing to the advantages such as low heat input, high welding speed, formability and high production rate. Due to these unique advantages, the potential of laser welding was evaluated for welding of a hypo-eutectic SSM aluminium alloy.Aluminium alloy A357 (Al-7%Si-0.6%Mg) was processed with CSIR-Rheo technology to the Semi-Solid Metal (SSM) state and cast into 4mm plates with a 50ton High Pressure Die Casting machine. The castings were subjected to heat treatments T4 and T6 and laser butt welding was applied to the heat-treated plates as well as to the plates in F condition.The tensile properties, hardness profiles and microstructure of the fusion zone, heat affected zone (HAZ) and base metal were examined. Comments on the microstructure and mechanical properties of the welds are presented.Welding of aluminium alloys poses many problems like porosities, lost of alloying elements, bead geometry and softening of heat affected zone. Laser welding is widely used in industrial production owing to the advantages such as low heat input, high welding speed, formability and high production rate. Due to these unique advantages, the potential of laser welding was evaluated for welding of a hypo-eutectic SSM aluminium alloy.Aluminium alloy A357 (Al-7%Si-0.6%Mg) was processed with CSIR-Rheo technology to the Semi-Solid Metal (SSM) state and cast into 4mm plates with a 50ton High Pressure Die Casting machine. The castings were subjected to heat treatments T4 and T6 and laser butt welding was applied to the heat-treated plates as well as to the plates in F condition.The tensile properties, hardness profiles and microstructure of the fusion zone, heat affected zone (HAZ) and base metal were examined. Comments on the microstructure and mechanical properties of the welds are presented.