What filler metal is commonly used for welding 6061 aluminum in TIG?

• A. 5356
• B. 4043
• C. 5056
• D. 309L

Answer: (B)

When welding 6061 aluminum with a TIG process, the filler metal is chosen to complement the alloying elements and promote a reliable, ductile bead. The common choice is an aluminum-silicon filler, because silicon improves the filler’s fluidity and helps prevent solidification cracking in the weld, which is especially beneficial for the 6xxx series like 6061. It also provides good corrosion resistance and a weld that is easy to work with in service.

Other fillers in the list are not as well suited for typical 6061 TIG welds. A magnesium-based filler can increase strength but may introduce cracking tendencies and different properties in the weld region. The stainless-steel filler is meant for stainless steel, not aluminum, so it won’t weld aluminum properly. The aluminum-magnesium fillers exist, but for general 6061 fabrication, the aluminum-silicon option is the most reliable and commonly used.