Engineering questions are rarely solved by one-word answers. A technician could write down “Yes” or “No” with some confidence, but there’ll almost always be an exception, an extra line of information that would perhaps be placed in parentheses behind the answer. And that’s the case with welding aluminium metal parts together. Yes, the work is feasible, but the answer is conditional. It all depends on the following factors.
The Welding Technique
A Gas Metal Arc Welding rig will get the job done right, but only if you know what you’re doing. Remember, this is a tricky welding situation. The alloy is soft. Avoid thin-sectioned workpieces; Material burn-through becomes a problem when thinner parts are welded. For a more equipment-biased outlook, consider a pulsed TIG rig, and always use the correct shielding gas. Oxidizing issues are common. Again, it’s the alloy that creates problems here, because, even when the same aluminium metals are being welded together, an oxidized surface won’t melt at the same rate as a clean alloy piece. Use one-hundred percent argon, due to its oxidization prevention and deep penetration features.
Don’t Miss the Troublemaking Details
The two aluminium parts look identical, but they won’t weld together. What’s the problem? Well, both sections need to be prepped and clean. Next, and this might seem like a simple question, one that any fabrication technician will surely have considered, but do you know if the two aluminium parts are sourced from the same alloy family? If not, you might be trying in vain to weld a non-weldable aluminium part. That’s a hopeless exercise. Many 2xxx and 7xxx series aluminium parts refuse to melt and bond. There’s copper in the 2 group and zinc in group 7, so don’t expect the parts to fuse easily. These alloys add trace elements as a property manipulation mechanism, perhaps even as a grain size manipulation tool, which makes the metals more sensitive to heat cracking.
At the end of the day, the act of welding two or more aluminium parts together is feasible, but great finesse is required. Inverter-based TIG (Tungsten Inert Gas) welding uses pulsed technology to precisely apply the join. A filler rod or wire blends with the parent metal to create a solid and robust weld joint. Incidentally, the Heat-Affected Zone (HAZ) must be meticulously prepped before this precision-based piece of equipment comes onto the scene. Again, dirt, oxidizing layers, and anodized coatings are not allowable. They’ll hamper or entirely invalidate the welding process. Otherwise, the job is good to go as long as the alloy families are both weldable.