Shielding gas issue
At work we weld the same Al assembly at two different sites. Everything is more or less the same except that one site uses pure argon and the other uses a mix (27%He, 73% Ar). The plant using the mix has problems getting the welds to meet specification, where as the one with the pure gas does not. The sections are 5xxx series and essentially a bracket is being welded to a thicker section.
Without getting into details (because that's about all I know at the moment), can anyone suggest any possible ideas why the mix might be giving problems (porosity etc) that would not occur with the pure
I think I'm about to be dumped in this one so I'd like to at least be able to sound like I might have a clue or two...