Aluminium Welding Services: The Importance of Using Proper Procedures to Avoid Defects

08 October 2019

Aluminium is a universally utilized metal. The tough material is lightweight and corrosion-resistant. Metal frames made out of aluminium are also thermally efficient. True, that’s a good feature to have when planning out a structure’s heat conductivity envelope, but welders don’t adopt quite the same positive outlook, not when it comes to joining this potentially heat-sensitive alloy. In other words, it’s not easy to weld aluminium.

Aluminium: Reviewing the Welding Headaches

Steel frames are weldable, although some super-alloys and high-carbon steels do require special attention. At any rate, you’re here to see why aluminium alloys can be hard to weld, not to worry about exotic steels. If you know anything at all about this popular fabrication metal, it’s that there a number of unique challenges to overcome when welding aluminium elements. For one thing, that thermal efficiency feature can actually sabotage the work, for the melting temperature of aluminium peaks at 660°C. By alloying the metal with other elements, that temperature rises, but then the alloying process introduces new issues, including crack propagation problems. With steel, there’s no such problem, not when it won’t melt until it’s superheated to 1500°C. As for those crack propagation issues, different grades of the alloy will crack when heated or they’ll transform dangerously, perhaps because the welding arc has caused the heat zone to undergo a transformative inter-granular change, one that produces a join undermining layer of precipitate material.

Utilizing Proper Procedures and Certified Welders

No worries, the defects can all be avoided. The best way to do so is to hire a welder who knows aluminium. The chosen journeyman should know all the ins-and-outs and challenges that could crop up during the welding of two or more aluminium elements. This individual will clean the alloy parts of oxide coatings, then remove oily deposits and dirt films. Done with the preparation work, the steel brushes and cleaning aids, there’s still the heat zone problems to address. Porosity propagation is a major headache here, for aluminium surfaces will chemically absorb hydrogen when they’re heated. Those tiny bubbles weaken the metal. Back with the procedurally skilled aluminium welder, hydrogen solubility headaches are combated by using material-specific shielding gasses.

The difference is found in the fine-tuning. Let’s clarify that slightly ambiguous statement. A material-savvy welder will bring in a special inert shielding gas to eliminate hydrogen solubility problems. To offset the gas mixtures unique blend, the equipment’s voltage rises slightly. The voltage increase is tiny, but it’s enough to overcome the ionization effect, as caused by the added argon. As for the cracking threat, magnesium and silicon-rich filler rods can help prevent such structurally undermining problems.