Laser Welding Aluminium Problems

Porosity in laser welds can be caused by plate.

Laser welding aluminium problems.

Laser beam welding can be used with crack sensitive materials such as the 6000 series of aluminum alloys when combined with an appropriate filler material such as 4032 or 4047 aluminum. In lbw of al li alloys the existence of the volatile element li increases the tendency of keyhole porosity which is caused by the violent vaporization of li. Porosity is a less critical defect in laser welds than solidification cracking. Laser conduction welding lcw 10 6 w cm 2 is comparatively stable and may offer an alternative means of welding traditionally difficult materials such as aluminum alloys.

In the past aluminum s high reflectivity was a problem for laser welding. The laser wavelength is 1 06 micrometers or less and a single 8 millisecond pulse is used. Laser welding problem of aluminum alloy 1. Copper and aluminum conductors are butt welded or corner welded by a two part process involving heating and melting the cu al interface with energy from a pulse laser and simultaneously generating a contact pressure.

A problem that can be easily encountered when aluminum welding is solidification cracking or the hot cracking problem. There are several different types of lasers that work well with aluminum and often the use of a cover gas is prudent. The laser induced plasma can influence the keyhole stability and thus the problem of keyhole porosity is more serious in co 2 laser welding than in yag and fiber laser welding. This problem is mainly due to the problem of aluminum alloy material.

However with the evolution of high power good beam quality carbon dioxide co 2 lasers and the advent of high power high brightness solid state fiber delivered lasers coupling the energy into aluminum is no longer an issue. Brittle intermetallics are found in the flash but the narrow fusion zone in the weld is. This form of cracking in aluminum is typically caused by a combination of metallurgical weaknesses of the weld metal as it solidifies with transverse stress applied across the weld. The likelihood of laser welds to suffer solidification cracking can limit the welding speed parent material composition or weld penetration depth that is possible when laser welding both steels and aluminium.

The problems linked to the welding of components having large thicknesses were examined in this work while referring to the operative parameters and analysis of the types of defects both internal and external that were encountered when setting up and in the laser co2 welding of these components. In this review the available research on the laser welding of 5xxx 6xxx and some 2xxx series automotive aluminium alloys is critically examined and interpreted from different perspectives.