Hello Gonzo, I believe you have been given one of those tasks that should be returned to sender for a rethink. Having said that, does this "part" end up being something like a spool? Could you apply the welds in an over-sized condition and have the extra material machined off afterwards? Or better yet, have the parts machined on a CNC lathe in one piece from 2" stock. Unless I'm missing something here, machining from a solid 2" stock would be the more economical and less technically challenging choice.
Having to pre-heat, messing with properly welding the thin end plates to the solid center part, dealing with warpage and distortion issues, and not losing tensile strength at the same time sounds like a nightmare to me. .090" and .100"+ fillets on something like this is a feat in itself and I would congratulate you on even accomplishing that. I'll be looking to learn something right along with you on this one. Best regards, Allan
Agree with Allan,
Inch and a half thick aluminum is not going to accomodate small fillets with GTAW.
They could be reduced in size somewhat with technique or an inverter power supply with frequency control and asymmetric current control of the AC cycle.
GMAW or GMAWP on a turntable would be the best way to reduce fillet size and heat input if the thing must be welded.