Research Of Narrow Gap Laser Welding Technology On Aluminum Alloy Plate

This paper is aimed at solving the problems of of traditional aluminum alloy plate fusion welding such as low efficiency, poor mechanical properties and large welding deformation, etc. Based on the laser welding experiments of aluminum alloy, the weld experiment of narrow gap laser welding has been carried out.Two methods of welding was used in the experiment, of which the welding weld defects and joint organizational performance were compared.the technical differences between the two methods were compared.The aluminium allay laser welding experiment showed that compared with the backward incline mode, the forward incline mode can gain a better weld bead forming, lager width/depth value, less air pore, finer grain size and lager micro-hardness. So, it is better to use forward incline mode if other conditions remain the same.In the mid-thickness aluminium plate experiment, narrow gap laser welding with filling wire technic has completed a 20mm thick butt joint with a laser with one bead of laser base welding and several beads of laser-arc compound welding. The welding efficiency is relatively low the formation of the weld beads is fair but has pore, incomplete fusion and cracks in it. tensile strength reach 65.5% of base metal. Narrow gap laser-arc welding technic has complete a 16mm butt joint with one bead a laser base welding and 3 beads of laser-arc compound welding, the The welding efficiency is relatively high the formation of the weld beads is fair with pore, incomplete fusion but no cracks in it. tensile strength reach 73.7% of base metal. Junction grains are typical columnar crystals and upper level has a finer grain size than the lower level. The micro-hardness increase from the lower to the upper bead.Compared with narrow gap laser welding with filling wire technic the narrow gap laser-arc welding technic can only weld a thinner plate but the welding efficiency is higher and the deformation is smaller, and has no crack in the welding beads. In conclusion, the narrow gap laser-arc welding technic can gain a better welding quality.