LASER-MIG HYBRID WELDING OF ALUMINIUM TO STEEL - EFFECT OF PROCESS PARAMETERS ON JOINT PROPERTIES

Laser MIG hybrid welding was recently suggested as a feasible process for joining of aluminium to steel for both structural as well as tailored blank applications. To promote an understanding of the process and the effect of process parameters on joint properties, laser MIG hybrid welding experiments were performed to join aluminium alloy AA6016 to DC05 zinc-coated steel sheets, in the thickness range of 1 mm, in a butt joint configuration. Among the process parameters varied were laser power, MIG arc power, wire feed rate, welding speed and arc position relative to the abutting edges. By metallographic cross-sections and tensile tests, the effect of these process parameters on joint properties such as wetting length, intermetallic phase layer thickness and tensile strength could be elucidated. Based on these results, a process parameter envelope resulting in adequate and reproducible joint properties (sound weld bead, sufficient and regular wetting, thin intermetallic phase layer, tensile strength exceeding 180 MPa) was established. Within this parameter envelope, corrosion behaviour was rated not critical, and forming behaviour showed promising results.