When Should You aluminum welds Preheat?
aluminiumsheet > 02-24-2018, 03:15 AM
Some people believe that all aluminum welds, both GTAW and GMAW, should be preheated. This isn’t true. In fact, if you have the correct equipment, preheat is rarely necessary.
Additionally, excessive preheat can severely degrade the mechanical properties. The last step in the heat treatment is aging, which is conducted at temperatures between 325 and 400°F. If you preheat to or above the aging temperature, you will ruin the alloy’s mechanical properties.
This is not to say that all preheating is bad. For example, if outside temperatures and humidity are very high, it is acceptable to preheat to 200°F to drive off moisture. Just don’t get carried away.