It’s often said that aluminum is a harder metal to weld than steel. And while it’s true that most welders start out by learning to weld steel before moving on to aluminum, it’s not entirely accurate to say that it’s harder. In general, welding aluminum is simply different, and requires a solid understanding of those differences in order to achieve a proper weld.
Challenges of Welding Aluminum
As we’ve discussed at length in previous blogs, aluminum and steel each have distinct characteristics, and the welding process makes some of those differences even more obvious than they might otherwise be.
Heat (thermal) conductivity is one that stands out in particular. As one might expect, because aluminum is considerably more heat conductive than steel, it also has a much lower melting point. However, aluminum also has a layer of oxide that allows it to resist corrosion, which is helpful in many applications, but has an extremely high melting point. A very clear understanding of how temperature affects aluminum is essential for skilled welders.
The other big difference is the relative solubility of hydrogen in liquid aluminum, which can lead to the hydrogen bubbles that form during the liquid stage of welding becoming trapped. This can result in porosity in the finished welds. If porosity is a persistent issue, it can often be mitigated by using a proper shielding gas, such as a helium/argon mixture. But again, if a welder isn’t accustomed to working with aluminum, porosity can become a big problem, as they may not know how to address it properly.
A Note on the Importance of Proper Filler Materials
Nowhere is it more important to use a filler selection chart than when welding aluminum. Filler charts are probably an aluminum welder’s best friend, because they take a process that could be quite complicated, and codify it in a way that’s standardized. The chart takes into consideration the eight primary characteristics that most impact welding, alongside the needs of the end product that is being fabricated, to give the welder the best chance of welding success.
About EVS Metal
EVS Metal is an American precision metal fabricator headquartered in Riverdale, NJ. We utilize the latest technology to cut, bend, weld and finish stand-alone items as well as parts for integration or assembly into more complex products. Our four ISO 9001:2015-certified metal fabrication facilities comprise over 250,000 square feet of vertically-integrated manufacturing space and feature the most modern equipment available, from welding robots and laser cutting solutions to automated powder coating lines.
We serve a diverse customer base across North America, providing a range of services from ITAR-compliant, quick-turn prototypes to high-volume production runs. Request a personalized metal fabrication quote online, or call (973) 839-4432 to speak with a specialist today.