Welding Certification test Q&A and tips and tricks
Emdubs
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    Wed Dec 04, 2024 6:13 pm

Aluminum tube to sheet
Aluminum tube to sheet
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Anyone have knowledge on the .25”, .040” wall tube to .060” sheet aluminum fillet test, where they cut it into 8 pieces and polish it?? I’ve submitted hundred of specimen to NDT and always have porosity or IF or both. Other people I work with have done hundreds and hundreds before passing. Something doesn’t seem right. Any help, knlwlege, tips, insight would be loved. Thss as nks
tweake
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i have no idea on the test, i'm not a pro so take anything i say with a bucket of salt.

first thing that jumps out at me is the cleaning looks horrible. any reason its only done in one direction? it looks like its missing a lot.
2nd is the weld looks huge for such a small rod. sharper tungsten, less arc length and smaller filler. i do know the wide weld for thin material thing, but it still looks big.
is it back purged? if your getting air or dirt in from the back side that can cause porosity. i would be sticking an argon tube down inside that pipe. make sure the inside of that pipe is cleaned.
add a bit more argon preflow.
hydrogen causes porosity, which comes from oils, or moisture in the material. you want to make sure the gas flow is enough to blow all that hydrogen and oxygen (and other crap) away from the weld pool before the arc starts.
tweak it until it breaks
Emdubs
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You have great points, I appreciate. The weld size thing tho. This is aluminum, TIG welded with a Lincoln transformer. The size requirement as per D17, I believe is, .060-.120 throat and leg. This weld is we’ll under .120
tweake
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fair enough.

one other suggestion, not something i've tried but i have seen others do it, is a back dam. trap the argon so it protects the back and sides a bit better. some build a foil dam, or use a 2nd tig torch with big cup to flood the back. to stop air/humidity getting in the back or side of the puddle as you move around.
tweak it until it breaks
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