[SimiWeldEngr]

I'm welding for a qualification test per AWS D17.1. The requirements are that the weld must be x-rayed. I have been practicing and sending courtesy pieces for the last month. Already completed my other materials, but this is the last one and cannot get rid of the porosity.

Just looking for any tips or tricks. Here's what I have so far:

Miller 280DX
1" diameter x 0.028" thick tube
6061 with ER4043 wire (0.045")
Groove weld, 1G
Ultra purity Ar torch and purge
Tube has been machined square
Machine deburr / break edge
Tube is chem cleaned
Tube is oven baked at 150°F
Wire sealed from supplier with Ar
Wire wiped 3X with acetone

Environment
25% humidity
95°F

Settings:
20CFH torch
20CHF purge
#5 cup ceramic
AC welding
no water cool
Frequency 100hz
Balance 60%
EN 100
EP 50
Zirconiated 0.8% White 1/16"
35° tip and flattened afterward
Tungsten "General" on 280DX

Any insight would be much appreciated. Thank you.

[Coldman]

I'd change two things if permissible by WPS:
- I'd get rid of the 4043 and use 5356 filler. 4043 is known for porosity and also not the best match for 6061 parent.
- Your DX will perform better with a different electrode. I had mixed results using it with my DX. I recommend 2% lanthanated for everything.
Good luck with your test and let us know how you go.

[SimiWeldEngr]

Thank you for the quick response. I think we have 5356 though I may have a WPS only for 5000 series base metal. But still Group IV, so I should be good to qualify.

I have lanthanated. We've tried it previously with no luck, but I've been changing EP / EN / Balance / Waveform / Frequency settings too. I'll post the results from xray tomorrow, and try some lanthanated again as well.

I was also suggested that we etch our wire, since that claim is that having parent metal etched but wire not does weird things because the metals are not equally treated....?

Thank you
Zach

[tweake]

i am no way qualified to give advice on this, but my $0.02 on it is try higher frequency and use pointed electrode, possibly even a narrow angle.
the reason here is with such thin wall tube, thats preheated, your amps required is going to be low. so its handy to reduce heat with the frequency and bump up the amps. that can help with control, give you more amp range to move in.

[cj737]

Your porosity is being caused by your flow rate. 20 cfh is way too high for a #5, and for a purge. Drop it down to 8-10cfh for the torch and probably 4-5cfh for the purge. You’re creating a Venturi effect with that much gas. 60 for a balance is probably a bit off too since the material is so clean and perfect. Bump up to 72 and try it again.

[SimiWeldEngr]

Just a quick update:

Prior to realizing that the gas flow rate was too high, we had systematically varied the settings as followswith everything else constant:

EP to EN from 1:1 to 1.5:1
Frequency from 100 to 250
Balance from 65% to 85%

The results were that the EP to EN ratio was most ideal at 1.25 to 1. The frequency was most ideal at 200. And the balance seem to be most ideal at 75%. There was still porosity, but it was substantially less than previously. Of course nowhere close to passing a Class B requirement let alone a Class A requirement.

Today we took the most ideal setting from above and now started to vary the gas flow, the wire type, the method of cleaning the wire, and the tungsten. All changes were one at a time and ran 2 of each change.

Torch flow - 10cfh
Purge flow - 0 or 5cfh
Filler - 4043 or 5356
Filler cleaning - etch or acetone
Tung - Zr 0.8% or La 2%

[cj737]

With all respect, tens of thousands of aluminum welds have passed X-ray with 60Hz, Pure tungsten on Transformer machines. The fact you have a Dynasty 280 and the most conscientious preparation should tell you it is not the Hz or filler. Even the tungsten you used is more than likely fine for the material thickness.

Gas flow and balance are the only places I’d tinker with to resolve your issues. Otherwise you may end up in analysis paralysis.

[BillE.Dee]

I'm trying to understand, why purge aluminum? or is it required? low purge is probably better. 2% lan may help. about 10 - 15 cfh at torch (verified with shooter). is this with gas lens or standard collet? wiping with acetone, removing oxidation and wiping again after all the cleaning you could use lower balance. are you pushing or pulling the puddle?

[Toggatug]

Going to guess the purge is for full pen with no oxide skin on the backside of the weld.

Pretty sure Jody did a video on it where he shows the difference of purge and no purge on some thin alum sheet.

Was quite an eye opener as to the difference.