Laser beam welding of wrought aluminium alloys

Laser beam welding is now a common manufacturing method for a wide range of steel products from automobiles to razor blades. However, the process has only recently been approved for critical applications involving aluminium a lloys, notably in the aerospace and automotive industries. The properties o f aluminium alloys influence the interaction between the beam and the mater ial to a far greater extent than for steels. The challenge of developing in dustrial welding procedures has therefore been considerable. The present re view describes the effects of CO2 and Nd-YAG laser beam processing paramete rs and the properties of the most common wrought aluminium alloys on the ch aracteristics of welded joints. Porosity, solidification cracking, and poor weld bead geometry are shown to be the most frequently encountered imperfe ctions. These can be eliminated through the use of appropriate filler mater ials, process gases, material preparation, and in some instances, adaptive control systems. Very little work has been reported on the corrosion proper ties of laser welded aluminium alloys. Experimental processing parameters a re presented and compared using an analytical model, which can also be empl oyed for predictive purposes. A number of industrial applications are descr ibed. These demonstrate that, for specific alloys, the process is now suffi ciently well understood to be approved for high volume production, particul arly in the transport industries.