Mig vs Tig for aluminium

[Hood]

Ok vid here, wire sticking a wee bit at the start but came away ok as I got into the weld. Bit hot for my liking for some reason, possibly because it was a smaller piece of 5mm Alu and I think I may have nudged to voltage up a bit when unwinding the spool gun from the welder, think I had 23v previously.
Anyway vid here.

Pic of etch, first showing it was the same part and second showing the bit that made a fool of me, full penetration plus

 

[Hood]

@henry Kadzielski
Any chance of you doing some similar tests when you get a chance, you are the only other person I know that regularly does Alu Mig welding.

 

[henry Kadzielski]

^^^ Good afternoon Hood, will look into it later today and report back. What I have is 6mm 5083 with 1.2mm Safra 5356. I am assuming these are all in the down hand position and we are talking about mig only? I will get 'Francis' to do standard mig, pulse mig and superpulse mig on the one sample and see what happens

 

[Hood]

Henry, yes just curious as to the currents you need for a sound weld.
Must admit I was really surprised at how low the current for the Mig was. I was expecting upwards of 180/190amps for the 5mm but 150Amps seems to be what it is wanting. I had never looked at the current before as I always just had it set to material thickness and on previous welders there was either no current readouts of if there were then they only showed whilst welding.
I did take vids of both the EWM and the R-Tech whilst welding to make sure of the current being used. The R-Tech you only see whilst welding but the EWM can be viewed beforehand although I wasn't sure if that would be the actual current whilst welding but it was.

 

[yorkie_chris]

Are you chaps using conventional torches for this or spool/pushpull?

 

[Hood]

I am using a Push/Pull on the EWM and a Spoolgun on the R-Tech.
Having said that I spent many years welding Alu on boats just with a standard Mig torch and teflon liner. You had to be careful not to bend the torch too much but otherwise it wasn't too bad. The 5356 and 5183 wire I use is a bit stiffer than 4043 so that helps.

 

[henry Kadzielski]

Good morning gents.
Sorry didn't get to do it yesterday afternoon as was told to COME HOME by the boss
Anyway as first photo shows all unwire brushed. Also all cooled prior to the next run.

First from the bottom
1)Francis in dumb mode standard mig just volts and wire speed 6.6m/min 24v
2) 6.6m/min 22v
3)Synergic standard no pulse 12.0m/min 23v 188amps this was her 6.0mm setting
4)Synergic pulse 9.5m/min 21.3v 160amps
5)Synergic double pulse 9.5m/min 21.3v 160amps this has hot start, creater fill and program has been modified by me somwhat
6)Synergic double pulse for 6mm outside corner vert up 8.0m/min 19.5v 136 amps this dosen't work so well in the down hand position

Photo all wire brushed

Photo of my 6mm vertical up setting

and wire brushed

etched welds

Just to confirm Hood, when I dropped the thickness down to 5mm current setting dropped to about 150amps. Also worthy note that there is better penetration on double pulse than on single pulse, that supprised me too. Welds 3 and 5 produced distortion (swelling ) on the reverse side. Most of the welds have excessive reinforcement so travel speed would have to be increased, but are indicative only.

 

[Hood]

Thanks Henry, yes when the Boss talks you must listen

Looks kind of like you were getting similar results to me regarding current etc, you were thicker plate so slightly more on the current but in range of what I would expect.

I had moved to using single pulse on a lot of the stuff I have been doing lately thinking I would be getting better penetration but it seems double pulse is actually slightly better. There is not a huge difference but even still I expected it to be the other way round. That is both of us that have shown that and with different machines so it more or less confirms that is the nature of the beast.

 

[Richard.]

Thanks Henry, yes when the Boss talks you must listen

Looks kind of like you were getting similar results to me regarding current etc, you were thicker plate so slightly more on the current but in range of what I would expect.

I had moved to using single pulse on a lot of the stuff I have been doing lately thinking I would be getting better penetration but it seems double pulse is actually slightly better. There is not a huge difference but even still I expected it to be the other way round. That is both of us that have shown that and with different machines so it more or less confirms that is the nature of the beast.

Henry’s results ain’t as close to yours as you think. It’s only his 190 run that comes in around the same penetration levels you were getting below 150. The rest of his at 160 look quite shallow compared to yours. They look very similar in depth to what you were getting at 150 with the tig.

 

[Hood]

Yes on a second look that is true, strange really as on the 188Amp one which is simple spray transfer it is roughly where you would expect when comparing to mine. Mine was 160Amps if I recall with the R-Tech but only on 5mm so another 15-20 amps for the extra 1mm thickness may be expected.
The first two seem to me to be too low on the wire feed speed, certainly when I compare to the R-Tech, I would have been around about 10-11m/min.
The shape of the weld penetration on the others seems more rounded like the tig on mine which makes me wonder if it could either be the focus setting on my EWM (I have it +1) or could it possibly even be the torch angle? I tend to use a very steep angle in the direction I am travelling.

 

[henry Kadzielski]

Good afternoon gents.
Yes the first two were just mig volts and wire speed. It's what 'Francis' had sown up on her dial, no idea what it was supposed to be, just pressed the trigger and noticed was too hot for that wire speed. Second was just reduce the volts somewhat. I use the synergic settings so don't have any idea what they should be set to manually. Third weld was just straight synergic setting for 6mm, however seemed too hot and travel speed was too low, there was also contamination of the top of the weld beed. The plate was new but from the scrap bin and was just wiped down with a rag. The pulse settings seem to be nicer in feel and appearence. All welds were done with a torch angle from the vertical about 30 degrees and leaning back 45 degrees, probably not ideal in the down hand position. The No.6 weld is my modified program for vertical up outside corner, so dosn'y require much penetration just to fill and seal without burning through

 

[Hood]

I found that when I went into Non-Pulse on the EWM it was wanting me to use crazy high currents for the thickness. I will see if I still have the first weld I did at the settings it threw at me, the alu actually split right down the centre as it cooled.
Not at the workshop today as not too well but hopefully I will be back tomorrow and remember to take a snap.

 

[henry Kadzielski]

Just a thought, are we needing full penetration from one side on alli plate, without and prep, as for me if I was doing this for a job and welding two plates together (butt) then I would mill out a prep about half the plate thickness and weld it then. That is was I had to do for my weld test in the overhead position.

 

[Hood]

Just a thought, are we needing full penetration from one side on alli plate, without and prep, as for me if I was doing this for a job and welding two plates together (butt) then I would mill out a prep about half the plate thickness and weld it then. That is was I had to do for my weld test in the overhead position.

No this was just meant as a comparison between penetration of Tig and Mig at comparable currents and welding a bead on a flat plate was suggested as the easiest/best method.

 

[henry Kadzielski]

I found that when I went into Non-Pulse on the EWM it was wanting me to use crazy high currents for the thickness. I will see if I still have the first weld I did at the settings it threw at me, the alu actually split right down the centre as it cooled.
Not at the workshop today as not too well but hopefully I will be back tomorrow and remember to take a snap.

Different machines and in my view similar results (can i say similar) I have never tried to do what we have done on this test before, so to see the different results from the different machine settings is good. I can say I never had any intention to use straight mig (no pulse ) on alli before and after this have no intention to do so

 

[Hood]

Different machines and in my view similar results (can i say similar) I have never tried to do what we have done on this test before, so to see the different results from the different machine settings is good. I can say I never had any intention to use straight mig (no pulse ) on alli before and after this have no intention to do so

I used to do it all the time as until recently I have not had a pulse Mig. I still occasionally use the R-Tech if the EWM is away on a job or in the car etc but if I have more than a few short welds to do I will try and do it with the EWM.

 

[henry Kadzielski]

No this was just meant as a comparison between penetration of Tig and Mig at comparable currents and welding a bead on a flat plate was suggested as the easiest/best method.

I do believe that with some fiddling I can get better penetration than what I have shown, but what is that going to achieve. I use 99% mig for alli due only to speed, can't remember when I used the AC /DC tig, tig for S/S for me OK good, as havent got the S/S mig solid or flux cored sorted, time short

 

[Hood]

Same here regarding SS, either Tig or stick. That may change in some instances soon as I have 3 rolls of flux core and just picked up a cylinder of mixed gas the last day so that I can give it a try.


I have always thought Mig was a stronger weld on Alu, mainly due to there being a lot more material in the weld than with Tig. Yes of course you can build up the Tig with multiple runs but it would take far too long.

There are times when Tig is the best, times when Mig is, times when stick is, they all have their place.

 

[Richard.]

Strength of weld is a funny one too and more so deemed by the knowledge and level of skill rather than process. Mig alu will always contain a higher level of porosity than tig. But tig will generally be a higher heat input process. Both Mig and tig can be prone to lack of fusion defects in a prep. One certainly isn’t “stronger”than the other consumable composition wise they are exactly the same. Strength is down to driving.
A lot more material in the weld does not mean strength in fact in most cases it means lack of. A lot of reinforcement particularly if it’s excessive means big stresses been put onto areas such as weld toes and larger heat affected zones. Neither are good when talking strength. A lower profile weld or a multiple run weld to get the fill is often a stronger more sound joint from a mechanical POV. Sticking a 8mm fillet on a 4mm gage is going to cause you more problems than a 4mm fillet in a 4mm gage.
Now Mig has speed on its side. This is good because it drops the heat input a lot offering better mechanicals. Over an equivalent sized run performed with tig. Now if distortion control Mig wins hands down.

 

[Hood]

Here is the pic of the weld that the EWM wanted me to do when I switched off the pulse and set to 5mm, next two I wound things down slightly but still way too high, turned it way down after that and got OK welds.
Not sure why it was so high as in pulse/superpulse modes it is very close to the settings I like.