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Up Topic Welding Industry / Technical Discussions / TIG, AL 6061, 4043 filler, and bad welds
- - By DaveSisk (**) Date 02-23-2003 17:17
Hi Folks:

OK, I finally got around to making something simple out of 1/8" thick Aluminum 6061 angle stock. (A generator dolly, simple angle stock made into a frame with casters attached...weld four angle cut pieces of stock together).

Man, this was hard! I was using 4043 filler, AC mode, tried a few different settings of the balance control on the ESAB Heliarc 161 AC/DC, was running at about 140 amps max. I made (for the most part) the ugliest welds I've ever seen. I kept burning through the base material, and could seem to get it to puddle well enough to dip the filler. Also, when I did dip the filler, it immediately solidified. They seem to be fairly strong welds, but they are ugly and craggy, and not consistent!

I'm trying to figure what I did wrong. My thoughts:

1) Didn't really clean the aluminum beforehand. I've done some test welds on aluminum, and it didn't turn out bad even though I didn't clean it beforehand, so I'm not sure if this is such a big factor. I did brush the area beforehand, but didn't clean with alcohol or any kind of solvent.

2) I used lanthanated tungsten rather than pure tungsten. I *think* this might be the biggest factor. The tungsten seemed to spit quite a bit (or at least, I think this was what's normally called "spitting"). If I set the balance control too far positive, the tungsten would melt off to the copper collet in the TIG torch. Move it just a bit too far negative, and I'd see the "pepper flakes" in the pool. I used the lanthanated tungsten simply because I didn't have anything else available at the moment (it was the weekend, and the welding supply's are closed.) I know the normal practice is to use pure tungsten. Would this help solve my problem? Would zirconiated tungsten work even better?

3) Welder skill? Maybe I just need more practice to get this right. Any pointers appreciated!

4) Perhaps the 6061 aluminum alloy is just too difficult to weld, given my limited experience at this point? What is the aluminum alloy that is the easiest to TIG weld? Which one (if any) can be fused (like steel) without needing any filler metal?

5) Any other thoughts?

Parent - By CHUB380 (*) Date 02-23-2003 22:15
Hi Dave, as far as I know you are using the right kind of tungsten. I also have an invertor type machine and a small assortment of thoriated tungsten came with it these seem to work fine, but everyone I talked to told me for my machine Ceriated or Lanthanated work best. Like I said I have been using the thoriated with good sucsess. For 1/8 angle I would set my machine up like this Ac-HIgh freq impulse-balance between 65-80% freq between 100-150% amp 125-150. 1sec preflow 15sec postflow. I am not sure what part of the angle you were welding but if your doing inside corners you would most likely have to turn the amps up, and also mabie turn your gas up and extend your tungsten so you can see. Also there is nothing more important than cleaning all joints before welding. I use a chemical solvent first and right beforeI weld I use a s/s wire brush. Hope some of this helps dont feel bad alum takes time. Also I would use a pointed tungsten with a small flat on the end. 3/32 for 1/8in alum. I not sure about 6061 but I think that is harder to weld than most Chub
Parent - - By ScottV (**) Date 02-24-2003 01:33
Try zirconiated 3/32 for that or red two% thoriated with your machine.I like the zicroniated the best for ac welding.Also I just love my new lincoln powermig 300 with the python setup just for stuff like that.I wouldn't even try firing up my Thermal prowave.That thing is to cool to believe on aluminum with pulse on pulse.

Also you pretty much need filler metal.5052 alloy with 5356 filler is a whole lot easier,atleast for me.I tried making something out with a econotig with 6061 T6 that was solid 1/2 inch,talk about ugly.the machine would snap off before you could get the puddle wet.way beyond that machine.I just grabbed my spoolgun setup,much easier.You couldn't even hold the torch it was so hot.How hot did the esab torch get?
Parent - - By DaveSisk (**) Date 02-24-2003 13:56

The torch got pretty warm! I could only weld for what seemed like a couple of minutes (was probably less) without having to stop due to the heat from the torch.

You made a good point that I didn't consider. I was using a 1/16" lanthanated tungsten, which I've found works well on steel 1/16" - 1/8" thick. However, I didn't consider that I was now running in AC mode (with part of the cycle DCEP), and probably should have moved up to a 3/32" diameter tungsten.

Parent - By Seldom (**) Date 02-24-2003 20:38
Most everything has been covered by the previous Repliers but I’d like to still offer some thoughts from my experience of welding 6061-T6 aluminum:

1. Cleanness is next to godliness!
2. Use pure tungsten
3. Cleanness is next to godliness!
4. Make sure you are using high enough amps so the end of the tungsten will “ball”.
5. Cleanness is next to godliness!
6. Only use a SS wire brush or Scotch pad to clean the base material and filler. Never use a grinding wheel or pad that’s been in contact with steel.
7. Cleanness is next to godliness!
8. Once the arc is initiated and you’ve introduced your filler rod into the gas envelope, NEVER remove it until you stop welding. Continue to dip but DON’T pull it from the gas envelope.
9. Cleanness is next to godliness!
10. If you sense you can’t get enough heat output from your equipment (torch specifically) preheat the base material to around 300 degrees. This is an accepted interpass temperature in most 6061 procedures, so by virtue of it being acceptable for interpass, it should be acceptable for preheat. Admittedly, I’ve had the occasion many years ago when I didn’t know any better to preheat aluminum higher then 3oo. It was common practice with my company to use a piece of pine to check for “adequate” preheat. As you heat the piece to be welded, we’d check the temperature by dragging a splinter of pine across the hot surface. If it left a scorch mark, it was ready to weld or flare for a lap joint flange (vanstone).
11. Cleanness is next to godliness!
12. With 6061-T6 materials don’t “wash-pass” without filler being added. Cracking very possibly will occur if the weldments are stressed.
Parent - By airweld (**) Date 02-24-2003 18:13
I have found Lanthanated tungstens to work well for both AC or DC. I would use 3/32" for 1/8" 6061 and the 4043 rod should work fine. Some alum stock is anodized which can pollute the weld so it should be removed. Try using what you have on hand to do that, ie. a big file, Scotchbrite disk or grinder and if that doesn't work any better you may have a gas leak or insufficient gas (or too much gas- 20 CFH is most you need). You are using pure argon, I assume? I looked at the Esab then bought a Lincoln 205. Couldn't get past the sound. Good luck, Scott. Page 4. Good alum info. Best alum info.
Up Topic Welding Industry / Technical Discussions / TIG, AL 6061, 4043 filler, and bad welds

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