Aluminum is emerging as an appealing alternative to steel in the welding market.  Welding characteristics of different metals are not universal therefore different procedures must be followed to properly weld aluminum. 

• In recent years, the use of aluminum in manufacturing has become more prevalent because of its light weight and other attributes that make it an attractive alternative to steel. But, those experienced in the welding of steel will find aluminum to be a different breed – the normal welding characteristics of steel don't always apply to aluminum.  
• Aluminum can be alloyed with a number of different elements, both primary and secondary, to provide improved strength, corrosion resistance and/or general weldability.
• Heat-treatable alloys are those that can be heated after welding to regain strength lost during the welding process. With the non-heat treatable alloys it is possible to increase strength through cold working or strain hardening.
• The reason why aluminum is becoming specified for so many jobs is its physical properties. 
• It can conduct electricity six times better than steel and nearly 30 times better than stainless steel.
• Aluminum provides excellent corrosion resistance, is easy to shape and join, and also is non-toxic for food applications. Since it is non-magnetic, arc blow is not a problem during welding. With a thermal conductivity rate that is five times higher than steel and being less viscous, aluminum can easily be welded out-of-position.
• Mechanical properties such as tensile strength, yield and elongation are affected by the choice of aluminum base and filler alloys. For groove welds, the Heat Affected Zone (HAZ) dictates the strength of the joint. In non-heat treatable aluminum alloys, the HAZ will be completely annealed and the HAZ will be the weakest point.
• New Welding Methods. The use of Constant Current power sources for the gas metal arc welding of aluminum has a long and very successful history. The use of “drooper” output has assisted in the delivery of a high energy axial spray transfer mode for aluminum that responds evenly and consistently with the proper welding current despite changes in arc length. The result of constant current is consistent penetration throughout the length of a given weld.
• Aluminum has many attractive attributes that make it the material of choice for a host of applications, although it can be different to weld. But, with a good understanding of metallurgy and the latest tools and technology on the market, aluminum can be dealt with successfully.

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