Aluminum Q&A

Q: I have a question related to gas tungsten arc welding (GTAW) of aluminum. Why are we failing to achieve complete root penetration on some T-joint fillet weld tests? This is being detected during the required macroetch examination and fracture test used for procedure qualification to AWS D1.2/ D1.2M, Structural Welding Code — Aluminum. We are using a Miller Dynasty® power source to weld 3/8-in.-thick 5086 Base Metal with 5356 Filler Metal. We are using a 5/32..