Which filler metals are commonly used for aluminum welding with GTAW or GMAW?

• A. ER4043 or ER5356 with GTAW or GMAW.
• B. ER308L with GTAW.
• C. ER70S-6 with SMAW.
• D. ER4047 with FCAW.

Answer: (C)

When welding aluminum with GTAW (TIG) or GMAW (MIG), you reach for filler metals designed to match aluminum chemistry and promote good flow and crack resistance. The most common choices are ER4043, an Al-Si filler, and ER5356, an Al-Mg filler. ER4043 helps with puddle fluidity and reduces cracking in heat-treatable and some Al alloys, while ER5356 provides good strength and corrosion resistance for a wide range of 5xxx and 6xxx alloys. Together they cover the typical needs of aluminum welding with TIG or MIG.

Other fillers shown aren’t standard for these processes with aluminum. A stainless-steel filler is not compatible with aluminum welds, and using a steel filler with a welding process intended for aluminum won’t yield proper alloy compatibility. The aluminum filler shown, ER4047, is used in some specialized cases, but it isn’t the common pairing for GTAW or GMAW as described in the question.