Welding Tips and Tricks

Hello All
We have been fighting porosity in our test samples and would like for a fresh set of eyes to look at this. Pipe will be x-rayed.

We have tried 100% argon and 25% argon 75% Helium flowing at 30cfm

Welding 6061-T6 pipe 1.25x.125 with a J bevel tacked in two places.
Pipe has been wiped down with acetone, then dipped in "Weldo" hydrofloric acid for two minutes and then cleaned again with cheese cloth and acetone.
The wire is Alcotec R5356 3/32 and it has also been cleaned with the same process.

The machine is a Miller Dynasty 350
Settings
EN soft amperage 120a
EP soft amperage 120a
Balance 74%
Hz 120
We have also tried pulse at 4.5 pps 75% peak and 25% backing.
Torch is a W375 water cooled torch running a # 8 cup with 1/16 2% ceriated tungsten.

Larger specks of porosity seem to be on the starts and stops everytime with tiny specks through out the pipe. This is a three pass weld root and two caps.

Any help or comments would be GREATLY appreciated.
TIA.

Just wondering, is 30 cfh a little high? Have you tried it with less flow?

Thanks Big Gear. We had upped the cfm while on the argon/helium mix. Will give it a go at 15-18 and see how that goes. Thanks for the input!

I'd increase your tungsten to a 3/32" as well...

I've never used that cleaning process before but I don't see why that would not work. Some of the guys here turned me on to Blue Gold cleaner and I have been very impressed with the results.

Post by Rick_H » Fri Nov 06, 2015 3:27 pm
I'd increase your tungsten to a 3/32" as well...

And do you have any good quality zirconium tungstens to try ?

https://www.diamondground.com/wolfram-t ... -tungsten/

http://www.ckworldwide.com/electrodes.html

cbfinn,
I know nobody wants to throw away rod, but more than one person on this forum including my son have had nothing but problems with Alcotec rods in 5356. I would replace the rod with another brand first and if the WPS allows I would switch to 4943 Maxal.

Len

Braehill wrote:cbfinn,
I know nobody wants to throw away rod, but more than one person on this forum including my son have had nothing but problems with Alcotec rods in 5356. I would replace the rod with another brand first and if the WPS allows I would switch to 4943 Maxal.

Len

I'm one of those people. I have scars from meteors produced by Alcotec 5356 in the 4G. The Oxford brand rod I'd run out of never once did that in three hours' welding. I tossed the Alcotec in the dumpster, and refused to continue until it was replaced.

Steve S

Thanks for the advise and quick replies. I talked with our welding supervisor about changing to a different wire brand as recommended here. He said that he has already talked to the "chief" about a better brand of wire but he is dead set on using Alcotec 5356.
Thanks again for all of your help! We have a good group of welders in the shop, and it helps knowing there is a possibility the wire may be causing us trouble, not our technique.

Seems light on amps to me. I like to set my machine to 150 EN/170 EP (that's not a typo) on 1/8" wall and move quick. The added EP could give you a little more pop on your cleaning.

I've had good luck with Alcotec wire over the past year. What sorts of problems have been happening. Granted I don't x-ray though, but it flows nice for me.


Greg H by Mike Zanconato, on Flickr

Thanks Zank, I will give that a try.
I have started grinding every pass to see where the porosity is getting in at. Looks like every start I have there will be guaranteed porosity and then just random places through the weld.
I will try to upload a cross cut pic of the pipe later on.

Just a thought, and someone may have already mentioned it, but are you pulling the filler rod out of the argon coverage when you weld? And are you cutting the end off of the rod before you start a weld?

Yes sir, We are keeping the tungsten to about 1/4 stick out, gas flow is now at 15 cfh and we switched to 100% ultra pure argon. We cut the wire off at least 1/2" everytime. Wire has been wiped in weldo...welded with, and then we tried wiping with just acetone. Still getting porosity in the starts everytime and some minor spots through out the pipe. Hopfully we will be able to try that MaxAL wire soon.
Thanks again for all of your input.

Sounds like you have tried most of the obvious things so here's a random thought - no chance it's a bad piece of pipe ? - unlikely but all the time you are on the go adding rod the silicon is scavenging any impurities but on starts / stops where you have to form a puddle prior to adding filler something boils out causing porosity ? I don't do much aluminum so maybe I'm way off - but it happens with steel a lot - any chance of obtaining some pipe from another batch to try ? - what happens if you try just running a bead round on the cut end of a piece without filler ? if that shows porosity it could be parent metal fault.

6061-T6 pipe 1.25x.125
Filler rod is Alcotec R5356 3/32

Is this new pipe and was it cleaned inside the entire length?
Contamination from inside pipe coming from some distance from the weld?
Just looking for clues.

Yes, new pipe that was machined dry without cutting oils. Pipes are 6 1/2" long with a J bevel.

We take a lint free cloth, soak it and the pipe in acetone, push the rag through the pipe, and wipe down the outside. Then it is submerged in Weldo (hydrofloric acid) for two minutes. Next the pipe is wiped dry of the acid, and then acetone is wiped near the joint.
The filler rod is scrubbed with scotch-bright pads and then wiped with acetone. New tigs gloves are used to handle the wire.
We never use any kind of abrasive wheel or air tools. Only a small stainless hand brush designated for AL is used at the joint.

http://www.arcalchem.com/Pages/WeldO.html

I think it says weld after wiping the Weld-O. Also 60sec soak not 2 min.Are Weld-O directions really being followed? Maybe the last acetone wipe is overkill and causing weird reaction with the hydrofluoric acid residue. I am not a chemist. Just a maybe.

What kind of material is the rag made of. If it's not cotton then the acetone could be breaking down the rag and leaving a film.???

Did some reading on acetone. Found out it is incompatible with acids. Your weldo is definitely an acid. I would try one cleaner or the other but not both. And you can freeze acetone at - 140 deg F. Just in case you want to.

Thanks for the replies.
I will give it a try today with 60 sec Weldo dip on the pipe and 60 seconds on the wire.
The rags are made by Contec and called CleanTube (TM) it is a Lacoste Knit.

Is it just me ? but unless that acid is very dilute it's some nasty s#1t - is there something in the WPS that requires it for this application because otherwise using new material that was cut without coolant it seems like it's not required - or is this level of cleaning something that evolved because you can't find the cause of the porosity ?

We started using the Weldo after our first set of tests failed xray for porosity thinking we didn't clean the pipe thoroughly . The coupons we used before Weldo were cut on a lathe with cutting oil, flapper wheel cleaned and then acetoned. I don't think I could get anymore porosity in the pipe if I tried. The flapper wheel just smeared the contaminants into the AL.

After all the new steps and procedures we have gone through, the porosity is still there...not near as bad, but enough to bust out on xray.
The only variables that have not been changed yet are the wire brand, and the AL pipe we are using for coupons. I hope we can get hold of the MaxAL wire and see how that helps.

Thanks again for your help and advise.

OK - having re-read the entire post it makes more sense - cutting oils can cause issues but I think there is something else missed right from the outset that none of us have hit on so I'm going to list my random thoughts & hope you find some something in them.

Amps seem low based on my welders dials but yours may vary - seems like it would take too long to establish a puddle & cause heat soak.

Amps seem on the limit for 1/16" tungsten - it may not be the problem but I'd go to 3/32" & anything except ceriated - had some once & hated it - never believed tungsten made much difference till I had it - never bought any since.

No.8 cup seems quite big for a relatively small weld on aluminum - also your original flow seems quite high - most people would likely use a 6 maybe 7 - some don't like gas lens on aluminum but I tend to just leave one on as I do far more stainless than anything else - the gas lens makes torch angle slightly more forgiving when going round smallish diameter pipes.

Straight argon will / should work - you have plenty of machine & it's not very thick though I've found a little helium helps on most alloys - not sure why but on my machine it just welds better - but NOT 75% - usually anything over 50% gives very strange arc issues - around 25% will work fine.

Have you tested very carefully for any gas line leaks ?

Have you tried changing gas bottles & / or adding a dryer ?

Can you achieve a porosity free weld on similar flat material where the gas stays put better - or even try laying two bits of you pipe side by side & weld them length ways down the valley.

Have you tried changing torches just to do a quick test - it's unlikely but I've had weird torch issues place I worked with a water cooled - brought a 26 from home to try & the problem went away - torch went back to supplier who said it was fine but I marked it with ultra violent marker & the the one we got back was a different torch ! I think it had a microscopic coolant leak that when the torch got hot enough created steam inside that got into the gas / ceramic - did like your welds but worse.

Can you get a sample of pipe from another batch to eliminate a base metal fault - it does happen.

Can you get any other filler wire to try to eliminate the problem ? it could be 4043 or 4943 just to prove the porosity even if this is not acceptable for the final production welds.

Can you beg / borrow / steal a positioner & rotate the pipe with the torch fixed to eliminate operator hand shake / torch angle while going round pipe ? if so try just running a pass round the pipe with no filler & see if anything much boils out of the pipe then try again running a bead on the outside with filler - only if these appear OK try a vee prepped open root - this would then show up anything that is coming from the inside of the pipe.

Is there any other job / process being done close by that includes spraying of anti splatter / silicon / paints / rust treatments etc ? these can travel in the air much further than you'd think & land on the tubing - also in this category is the possibility the pipe was contaminated in a similar way somewhere in storage / transit from the manufacturer to you.

Sorry this went on a bit - but I think you have to go back to basics & eliminate 1 thing at a time - the extra cleaning would appear to improve things but clearly is'nt the cure - I would think " Otto " may chime in on this one as he has I believe done repairs on similar pipe & had to achieve X ray welds onto old corroded in service pipes.

Thanks Noddybrian I will try to answer what we have done under each suggestion

Amps seem low based on my welders dials but yours may vary - seems like it would take too long to establish a puddle & cause heat soak.
We are using a foot pedal are running about 115-120 amps with a 200amp upper limit

Amps seem on the limit for 1/16" tungsten - it may not be the problem but I'd go to 3/32" & anything except ceriated - had some once & hated it - never believed tungsten made much difference till I had it - never bought any since.
We are now trying pure tungsten 3/32 and zincronated 1/8

No.8 cup seems quite big for a relatively small weld on aluminum - also your original flow seems quite high - most people would likely use a 6 maybe 7 - some don't like gas lens on aluminum but I tend to just leave one on as I do far more stainless than anything else - the gas lens makes torch angle slightly more forgiving when going round smallish diameter pipes.
We have tried several different sizes of cups, all with a gas lens, with about the same porosity results. The argon is flowing @ 13-15 cfh now.

Straight argon will / should work - you have plenty of machine & it's not very thick though I've found a little helium helps on most alloys - not sure why but on my machine it just welds better - but NOT 75% - usually anything over 50% gives very strange arc issues - around 25% will work fine.
The helium mix was all we had at the time and wanted to try something else to troubleshoot the gas. We are back on the 100% argon now and have the 100% ultra pure bottle on standby

Have you tested very carefully for any gas line leaks ?
Without tearing into the machine we can only soap test fittings and watch the ball drop on the regulator, all check good. I have thought about bypassing the machine and just run a line from the bottle just to see.

Have you tried changing gas bottles & / or adding a dryer ?
Yes, three different bottles, 2 different gasses. We don't have a dryer.
Would a dryer be something to consider?

Can you achieve a porosity free weld on similar flat material where the gas stays put better - or even try laying two bits of you pipe side by side & weld them length ways down the valley.
We have tried this on a 1/4" AL plate and are getting some porosity in the root, but very little if any in the filler or cap

Have you tried changing torches just to do a quick test - it's unlikely but I've had weird torch issues place I worked with a water cooled - brought a 26 from home to try & the problem went away - torch went back to supplier who said it was fine but I marked it with ultra violent marker & the the one we got back was a different torch ! I think it had a microscopic coolant leak that when the torch got hot enough created steam inside that got into the gas / ceramic - did like your welds but worse.
Yes we have tried 2 different air cooled and 2 different water cooled torches.

Can you get a sample of pipe from another batch to eliminate a base metal fault - it does happen.
We only had a few sticks of pipe to test with and they all came from the same vendor.

Can you get any other filler wire to try to eliminate the problem ? it could be 4043 or 4943 just to prove the porosity even if this is not acceptable for the final production welds.
4043 should be arriving tomorrow.

Can you beg / borrow / steal a positioner & rotate the pipe with the torch fixed to eliminate operator hand shake / torch angle while going round pipe ? if so try just running a pass round the pipe with no filler & see if anything much boils out of the pipe then try again running a bead on the outside with filler - only if these appear OK try a vee prepped open root - this would then show up anything that is coming from the inside of the pipe.
This was the biggest help so far! Huge reduction in porosity.


3/32 wire and pure tungsten


Root pass 37 1/2 to a J prep no gap, no purge. I wanted to simulate the test as much as possible.

Is there any other job / process being done close by that includes spraying of anti splatter / silicon / paints / rust treatments etc ? these can travel in the air much further than you'd think & land on the tubing - also in this category is the possibility the pipe was contaminated in a similar way somewhere in storage / transit from the manufacturer to you.
None. Clean climate controlled area we are working in.

Sorry this went on a bit - but I think you have to go back to basics & eliminate 1 thing at a time - the extra cleaning would appear to improve things but clearly is'nt the cure - I would think " Otto " may chime in on this one as he has I believe done repairs on similar pipe & had to achieve X ray welds onto old corroded in service pipes.
Really appreciate the in depth input Noddybrian!

We have found that all the porosity occurs somewhere at arc start up. We are getting less porosity if the arc fires immediately and does not wonder any. The tungsten must be sharp with no ball for the machine to do this. The best result we had today is for the arc to fire like a switch, give it a second, and taper off the foot pedal. This will leave what looks like a pop rivet in the flat plate. No porosity.

Interesting it's worst at arc start up - any chance the pre-flow is too short or there is a restriction or just so much length of torch hose from the machine that the arc is started before full gas cover is achieved ? or the first time the filler was introduced the end balled up from lack of gas cover / filler / torch angle ?- It's kinda hard to diagnose things remotely or put it into words - most times if someone experienced is there in person they will see something that points to the issue - I had hoped one of the guys that does more aluminum would have read this & had a revelation - it can take a while with working hours & world time differences - on the tungsten I would'nt use pure on a modern inverter though some that grew up with it may - zirconiated should be OK but Jody likes 2% Lanthanated & if says it's good then it must be - most work fine on DC but make strange shapes & give arc start issues so for your problem I'd experiment with what holds the best taper on your machine - many swear by E3 or Lazer & although 3/32" is quite capable of the current your using I've found that going to 1/8" with a longer taper & balling just the tip on a piece of copper works well & seems to hold it's shape better.

That's about as much as I can think of - best of luck getting a handle on this & maybe Zank / Otto / TamJeff or another of the experienced aluminum guys will have further insight given time.