Aluminum Welding Electrical Requirements

Aluminum welding relies on electricity to generate heat in the aluminum.

More and more manufacturers are using aluminum in various engineering applications because aluminum is more lightweight than other metals such as steel. As a result, more welders must learn how to effectively work with aluminum welding. Welders make aluminum more workable by sending electricity through the aluminum alloys. The electricity causes heat to build up in the aluminum until the aluminum becomes workable.

Zinc

Aluminum alloys have various strengths. Unfortunately, some of the strongest aluminum alloys are not very weldable. The strongest aluminum alloys are aluminum combined with zinc, which are a part of the 7000 series. These alloys play an important role in space travel. The 7075 aluminum alloy is sometimes welded for the injection molding industry, but welders normally do not use this aluminum alloy for structural engineering.

Magnesium and Silicone

The next hardest series, the 6000 series, uses aluminum, magnesium and silicone. While welders can work with this material, the material has a high chance of cracking, which can ruin the workpiece. When welding, welders always must use a filler metal.

Magnesium

The 5000 series is for sheet and plate metal. This aluminum is combined with magnesium and is always weldable. The 4000 series has aluminum and silicone and is used either for welding or brazer materials. Aluminum and magnesium metals are very weak and are mostly used for packaging, such as with carbonated drink cans.

Heat and Integrity

To weld with aluminum, the aluminum must be combined with another alloy. The original aluminum is always stronger than the alloy because the aluminum starts to lose some of its mechanical properties when heated at temperatures above 400 degrees Fahrenheit.

Alternating Currents

Aluminum must be welded using alternating currents instead of using direct currents. The tungsten electrode needs more energy to perform the same work when using alternating currents. Welders should use pure tungsten or zirconiated tungsten as a result.

Tungsten

Since the aluminum needs an alternating current to weld, the welder must use a much larger electrode than when working with other materials. Welders use zirconiated tungsten if they need more electrical current.

Conductivity

When working with aluminum, welders must take into consideration that aluminum has very high electrical conductivity. This is very beneficial when creating electronic applications, but welders must be careful when currents pass through the aluminum. Welders can use long contact tube guns when working with the aluminum because there is no electrode resistance heating. The conductivity requires that the welders use more heat to weld the aluminum, since much of the energy passes through the aluminum.

References

• Lincoln Electric: Aluminum GMAW Welding Guide
• Lincoln Electric: Frequently Asked Questions in Aluminum Welding
• Key to Metals: Welding of Aluminum Alloys