TIG welding aluminum issues, please give advice.

[shenion]

ive only ever used 5356,never had them grainy?

Seems to be the nature of the beast for old transformer machines. Less of an issue on inverters. Lots of stray arcs (just like the area around the weld.).

It does look like too big an arc length and overheating the weld pool. It should get better with technique.

 

[Shox Dr]

i asked earlier in the thread,but the op said they werent cleaned after welding.presumed the grainy bead appearance was a minor gas leak then,as there wasnt even one shiny bead

In post number 6, the first picture shows a 90* mitre: the one intersecting hasn't been cleaned and the other barely enough.

The rest show what looks like cleaning after the joint has been made, and after been welded

 

[hotrodder]

You could try drilling a hole in the tube that's not scalloped, it will be covered by the scalloped tube. It might help relieve the pressure.

Waste of time, will achieve nothing...............

Wendel is suggesting drilling the unscalloped tube so that the hole ends up centred under the weld and all the short tubes vent into the longer ones. Pretty much everyone i know does things this way unless there's no choice... piece of tube welded to solid at each end for example

There are a combination of errors, but would say, lack of experience is a major factor. Practice will get you sound welds on tube to tube.

Although I am going back years ago and, if I use ROV's as an example. All marine grade alloy, 6mm plate, tube, solid round bar ect.

I had no cleaning action on my old BOC ADR 300, ROV max depth was 10.000 FSW. I never had a dipper on a mega buck ROV.

OP is welding tube, do you all think this cleaning action stuff is really relevent??

Cheers..........

Do we have to have this debate again? My opinion is the same as it was last time... agree completely that welds of the highest quality can be done on an ancient/basic machine with no bells & whistles. If the machine has user adjustable AC balance then you need to understand it and how to set it. Thread i linked to is a case in point, Malcolm found life a lot easier once the balance setting was tweaked as it was set wrong and as his Syncrowave is adjustable from 45% - 68% EN i.e. it can be set to either provide more cleaning than a fixed/basic machine (50%, same as it comes out of the wall) which'll turn the end of the tungsten into a football or set to provide less cathodic cleaning which can result in a sluggish weldpool full of oxides. Mine can be set to 35% EN which'll make a right mess if you weren't expecting it/didn't understand balance and thought it'd be useful

Was using the welder this afternoon and did a quick tube joint, no stainless brushes or solvents were used but bear in mind what Shox said about pre weld cleaning...

Start off with a tack made with too long of an arc length (not enough amps/no patience can also have the same result), can see that i melted both tubes away from the root of the joint and bridged with filler, result is lack of fusion at the root. Note also that i filed back the feathered edge of the coped joint.



Two shots of the finished weld, you're not supposed to notice the crater i left the relevant bits are the tacks with lack of fusion being much wider than the rest of the weld




Had a blonde moment when i sectioned it and cut it in a way that means the part of the weld with LOF isn't visible anymore The goal with a fillet is to get fusion at the root and deposit a weld of sufficient size for the wall thickness


The red circle corresponds to the the crater i left, crater itself is a stress riser and we have a localised reduction in wall thickness at the same spot...

FWIW i turned the frequency down to 60Hz, dunno what the balance was (70 something % EN), 2.4mm tungsten (as that was already in the torch) and 1.6mm 5356. Around 100A pedalled, 1 1/4" 16swg (no 1/8 wall in stock)

 

[Rrunnach]

Wendel is suggesting drilling the unscalloped tube so that the hole ends up centred under the weld and all the short tubes vent into the longer ones. Pretty much everyone i know does things this way unless there's no choice... piece of tube welded to solid at each end for example

I didn't have a choice, WPS dictated, I was merely passing on what worked for moi!

Do we have to have this debate again? :hug: My opinion is the same as it was [URL="http://www.mig-welding.co.uk/forum/showthread.php?t=33791&highlight=fillet"]last time[/URL]... agree completely that welds of the highest quality can be done on an ancient/basic machine with no bells & whistles. If the machine has user adjustable AC balance then you need to understand it and how to set it. Thread i linked to is a case in point, Malcolm found life a lot easier once the balance setting was tweaked as it was set wrong and as  his Syncrowave is adjustable from 45% - 68% EN i.e. it can be set to either provide more cleaning than a fixed/basic machine (50%, same as it comes out of the wall) which'll turn the end of the tungsten into a football or set to provide less cathodic cleaning which can result in a sluggish weldpool full of oxides. Mine can be set to 35% EN which'll make a right mess if you weren't expecting it/didn't understand balance and thought it'd be useful

No debate required, I agree if you have the bells and whistles, fundamentals are required. For certain applications, I just wonder why the fuss, tack it, nail it, job done!

Was using the welder this afternoon and did a quick tube joint, no stainless brushes or solvents were used but bear in mind what Shox said about pre weld cleaning...

If I wire brushed every weld on al/al, I'd have been out of a job, got done when required.

Two shots of the finished weld, you're not supposed to notice the crater i left :whistle: the relevant bits are the tacks with lack of fusion being much wider than the rest of the weld

Craters are good for the soul

Ps.............oops, summit not right!!

 

[hotrodder]

Gotcha

Ps.............oops, summit not right!!

Used code tags (#)

instead of copy and pasting the

when breaking up post. Still makes sense and probably faster

 

[Georgie]

Looks pretty stout hotroder! Would like to see if you cab rip off one of the welds to see what it looks lile. How many times do you stop to reposotion your body? Also, your machine is watercooled?

 

[hotrodder]

Too late to attack it with a BFH as i sectioned the weld- the plan was to show a clean weld with no brushing/solvents & balance biased towards EN, the effect of the crater on cross section and the void due to LOF from the tacks with too long of an arc length. Messed the last bit up when i was cutting it but pic here http://www.millerwelds.com/resources/articles/common-TIG-GTAW-welding-problems-visual-guide-graphic figure 4
I would have had to destroy the tube to break it and it should've broken in the HAZ next to the weld. In real life it's normally fatigue that kills things rather than brute force which is why destructive weld testing normally involves cutting test strips that are then bent and/or etched and examined for flaws/inclusions etc

Yeah, watercooled and i did the weld same way you are- in quarters with it laying on the table.

 

[Georgie]

I wish one day i could weld as neat as that, but i know ill never be able because of a slight advantage yall have over me... But i will do my best to apply all of your input on this matter and will keep updating with progress pictures.

 

[hotrodder]

Give it time and you could be surprised, most of it is practice (muscle memory/reading a weldpool etc) but it is important to practice the right things to avoid developing bad habits that'll end up hindering progress in the longterm. I promise you that progress will be a lot faster and less frustrating if you go back to flate sheet/plate. Learning to maintain arc length is a LOT easier on flat stuff as the angles of attack are constant rather than changing. With less going on at once the brain spends more time learning and less playing catch up. Get competent at butts and fillets in a downhand (flat on the table) position followed by horizontal and vertical and by the time you go back to tube much of it will be second nature leaving you free to concentrate on torch/filler relationship as you work around tube
Not that different to learning a musical instrument in many respects

 

[Rrunnach]

Not that different to learning a musical instrument in many respects

You probably get paid more playing a musical instrument, don't breathe in cancerous fume, or have groupies lining up outside your bay, wanting one

 

[FASTdan]

Ceriated is just **** IMO regardless of what's being welded.

Does that apply to use on an inverter machine for alu also? I swapped to grey some time ago (when I was less experienced and using a cheaper chinese machine) and have continued ever since - but more out of habit/laziness than anything else.

Maybe I should try some white again?

 

[Wendelspanswick]

I use white (zirconated) with my inverter on Aluminium, on 1.6mm and under I don't bother grinding a point, just use the end as it comes and turn the frequency up to narrow the arc.

 

[hotrodder]

The ceriated thing applies to welding anything with any machine personally but ask ten welders and you'll get 10 different answers... some hate 'em, some like 'em, some don't care and/or have never tried other flavours while others can't keep the tungsten free of contamination for long enough to notice any difference

This looks at the differences with regards to electron work function (ease of striking and arc stability) and erosion... http://www.bssa.org.uk/cms/File/Gas%20Tungsten%20Arc%20Welding%20Electrodes%20for%20Stainless%20Steels.pdf I don't like ceriated as i found the tip errodes more quickly than any other flavour with DCEN so they need touching up more frequently, they don't ball as well as zirconiated or lanthanated with AC on a transformer machine and can't be kept sharpish like lanthanated can with AC on an inverter

 

[pedrobedro]

I've used ceriated for everything, grind a point and just flat the end off and it welds no problem. I think it's just what you get used to and different machine characteristics.

 

[rohart]

In post 59 the OP shows the torch positioned for the hardest part of the weld to reach. I was struck by how little the electrode was protruding. Especially when he's using a gas lens which should allow more stick out because of the laminar gas flow it is designed for.

I've felt that all his welds are rather large and high current, and if he's keeping his arc as long as it appears, it seems to me that this is a contributing factor in his problems.

 

[Georgie]

Ok rohart..about the current im runing.

Im set at about 155 amps, and im pedaling to the max to start the pool then backing off about 1/4 travel to keep it going. My angles and distances obviously need practice, especiay that i only have one eye, so i know tgats probably a factor. For the electrod lenght, what do you suggest on a #7 cup?

 

[Georgie]

Ok, the BIGGEST improvements were from Shenion post #57 and Rrunnach post #65.

After drillling holes in all mating pipes, my welds are much better. Also, keeping 90° like Shenion said is whave to focus on. My welds are MUCH better after focusing on these aspects.

I started spliting the dutys of holdding the torch with my right hand to my left hand..which greatly increased the amout of welds per/time. I thinks that led to my first hole in about 20 welds.. I guess with the increase in welding speed the heat caught up, even tho i drilled the mateing pipes..

Also, a big time problem in my hoses+cable to the torch... WAY to much memory on the torche "cables"...
IE; it alows me to turn the torche better with my left(lol) than my right..and i DEFINITELY feel more comfortable with holding the torche in my right hand... Anyone know any better cables for my type of machine? I need flexibility!, w

Thanks,will post pics tmr

 

[Georgie]

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[Drains]

Georgie, you need to lose the craters. They are serious stress raisers and your joints are very likely to fail. When you finish the weld, have a slope down on the current or back off in the pedal, and do a wee circle with the torch, or add a wee bit of filler, or both, just to even things out.

Other than that, nae bad.

 

[Georgie]

I heard down slope time is for pussy's. How long should i keep reducing the pedal once the last pool is full?

Thanks