Welding aluminium is unique, compared to welding other common materials like steel, because of its chemistry and tendency to crack.
Aluminium forms an oxide layer that has a higher melting temperature than the actual metal itself. In order to avoid un-melted aluminium oxide particles in the weld, an oxide removal process, such as wire brushing or chemical cleaning, needs to be applied before welding. Additionally, some aluminium alloys, are artificially aged to increase strength. The heat from welding destroys the benefits of ageing and large reductions in strength can occur in the heat-affected zones. Therefore, post-weld artificial ageing may be required for these types of alloys.
There are further complications, such as that you generally cannot use the same type of aluminium alloy for the weld filler and the exact type to be used depends on multiple other factors.
Essentially, aluminium welding not only requires modified techniques to steel welding but also an experienced professional to advise on the best choices for your project.
One of the most common welding techniques for aluminium is gas tungsten arc welding (GTAW), otherwise known as tungsten inert gas (TIG) welding. The GTAW process is extremely clean, which prevents aluminium from being contaminated by the atmosphere and gives consistent results. It also does not require mechanical wire feeding which simplifies setup and can be used in a broader range of situations.
MIG welding uses an electrode for the wire that is continually fed at the base of the weld. The wire is shielded by inert gas. The method is often messy because of the trace of tiny metal beads that are left behind as a result of using the spray transfer method. For experienced welders, this method is more controllable with a cleaner result. However the weld will usually require clean up.
Royal Fabrication has extensive experience of aluminium welding. Whatever your project, you can be secure in the knowledge that we have the expertise to make sure things are built to last.
Get in touch with us for all your aluminium fabrication and welding needs!