[amateurwelder]

Hello All,

Thank you for reading this post. I am inside welding 3/16" carbon steel plate with 2 2% Lanthanated Tungsten Electrode 5/32 and filler rod. I am using a number 8 cup with 15 cfm argon. I have a few of these to do, but after about 4" of weld my tungsten starts to melt. I am running at 190 amps dc -.

Thanks again!

Jonathan

[Braehill]

Jonathan,
You are using DCEN correct?, if not you should be. Everything else you mentioned should be well within the limits of a 5/32 tungsten. You would probably be fine at 1/8".

Also make sure that your collet doesn't have a twist in it, they can swell out against the sides of the torch and block off the gas flow. Never torque down on the back cap when it's hot.

Len

[amateurwelder]

I am using electrode negative... 7 balance and 9 post flow.

[Braehill]

Balance only comes into play during AC welding so you don't have to worry about that.

Clean a piece of metal shiny bright and hold your torch straight down on it at about a 1/8" arc gap and light up until a puddle forms and let off without moving the torch for about 10 seconds, if it stays shiny and your tungsten stays shiny we can eliminate gas problems.

Len

[Braehill]

100% Argon correct?

Len

[gnabgib]

DCEN. But why 190 amps? I would be on 90max tho that won't be the cause of your problem.

[TRACKRANGER]

DCEN. But why 190 amps? I would be on 90max tho that won't be the cause of your problem.

I have to agree with the question on the high value. But I thought it might definitely contribute to the problem. Try lowering the current and see if this changes your resultant problem with the electrode.

Trev

[Oscar]

He could be using a foot pedal to modulate the actual current output. At 190A, seems like a suitable high limit for 0.187" thick steel, unless it's near a corner or edge.

[gnabgib]

I have to agree with the question on the high value. But I thought it might definitely contribute to the problem. Try lowering the current and see if this changes your resultant problem with the electrode.

Trev[/quote]

Maybe the excessive amperage is negating some of the shielding benefits of the gas?

[Braehill]

Jonathan,
You should be able to run 190 amps (not that you need to for 3/16") all day with a 5/32" tungsten and it not melt if all else is in order. There's underlying problem here that we haven't got to yet.

My question would be, what would be the reason to use 5/32" tungsten and filler rod on 3/16" carbon steel? If we have that big of a gap, we should be beating the fitter with the 5/32" filler. If it's just practice and it's all you have on hand, but that's the only time I would be so inclined.

Len

[MinnesotaDave]

Nothing wrong with 190 amps on 3/16" material - I like it for fillet welds and use 1/16" filler and 3/32" tungsten.

There is something wrong with your setup. What machine are you running?
If you are running a miller Syncrowave 250, the balance is set at 3 during DC welding.

image.jpg (51.65 KiB) Viewed 951 times

Btw, flow rates are CFH, not CFM - probably just a typo.

[MinnesotaDave]

DCEN. But why 190 amps? I would be on 90max tho that won't be the cause of your problem.

Respectfully, you are in error. 90 amps on 3/16" material is much too cold.

With the exception of an open root, knife edge - 90 amps will work fine there.

[amateurwelder]

Sorry... I am welding 1/4" plate. The reason I switched to 5/32 because I thought my tungsten was melting away... I had touched the puddle a few times and actually think now that it could have been the problem all along. I have attached some pictures of the tungsten and one of the welds.

I made a note that balance should be set to 3.

Thank you again for your posts!

Jonathan

[Oscar]

dipping the tungsten and continuing is a big no-no. Posting up those pictures would have saved everyone a lot of time in the replies as well.

You have to stop, and if severe enough as in your case, you need to slice off the contaminated portion and re-sharpen. You will get massive arc wander and contaminated weld beads if you don't. So no your tungsten isn't melting/vaporizing/dis-integrating, hardly the case. You just need practice to steady your hands.

How well are you seeing the actual tip of the tungsten and the puddle itself?? Lots of times, the helmet lens clarity (or lack there-of) contributes much to these problems. You have to be able to see the tip of the tungsten and the puddles as two separate entities. FWIW, you would be fine with a 1/8" tungsten. Sharpen up, then put a flat on the tip.

[TRACKRANGER]

Yes, a picture tells a thousand words. Cause of problem clearly identified.

Try to get yourself in a more comfortable position, this will assist you to keep a more steady approach and avoid dipping

Trev

[rick9345]

Dipping potato chips and other snacks OK

Dipping tungsten as stated NO! NO! avoid the dreaded green umbrella shape/glow on the puddle. clean/resharpen

[dunkster]

If you are running a miller Syncrowave 250, the balance is set at 3 during DC welding.

Dave-
I'm running a SW350 here and has always been my understanding that AC balance is a moot adjustment when it comes to DC GTAW, but does become a dig function in stick mode. Am I misinterpreting here or have I been missing something all along?

[Oscar]

If you are running a miller Syncrowave 250, the balance is set at 3 during DC welding.

Dave-
I'm running a SW350 here and has always been my understanding that AC balance is a moot adjustment when it comes to DC GTAW, but does become a dig function in stick mode. Am I misinterpreting here or have I been missing something all along?

That varies from machine to machine. One cannot make such a broad generalization. That is what owners manuals are for.

[gnabgib]

DCEN. But why 190 amps? I would be on 90max tho that won't be the cause of your problem.

Respectfully, you are in error. 90 amps on 3/16" material is much too cold.

With the exception of an open root, knife edge - 90 amps will work fine there.

Ok. My last job was 4mm, but yes, welded from both sides. Also root run on 6mm beveled/open root at 110-105amps.

[Braehill]

I've welded 4" XXH pipe with an air cooled 150 amp torch, the wall thickness on that size pipe is around 5/8" thick, so if I can do this, why would anyone need 190 amps to weld 3/16" plate?

If you guys get a chance, weld with a 150 amp air cooled torch for awhile at 160 amps and see how long you can hold on. We weld everything here at work with one so it seldom ever sees more than about 140 amps and we use a lot of XXH pipe up to 8" (.875 wall).

I've even heard Jody say on more than one occasion that 160 amps is all you'll ever need on Carbon steel. You definitely don't need 190 amps to weld 3/16" Carbon steel.

Len

[Braehill]

If you are running a miller Syncrowave 250, the balance is set at 3 during DC welding.

Dave-
I'm running a SW350 here and has always been my understanding that AC balance is a moot adjustment when it comes to DC GTAW, but does become a dig function in stick mode. Am I misinterpreting here or have I been missing something all along?

That varies from machine to machine. One cannot make such a broad generalization. That is what owners manuals are for.

We have an older SW350 and it's marked to set the balance to 3 on the front panel for DC welding and so are the older SW250's, the newer machines are marked Balance/Dig. But what Dave said was not in any way a generalization when he referred specifically to a SW250 and put a picture up to back it up.

Len

[MinnesotaDave]

I've welded 4" XXH pipe with an air cooled 150 amp torch, the wall thickness on that size pipe is around 5/8" thick, so if I can do this, why would anyone need 190 amps to weld 3/16" plate?

If you guys get a chance, weld with a 150 amp air cooled torch for awhile at 160 amps and see how long you can hold on. We weld everything here at work with one so it seldom ever sees more than about 140 amps and we use a lot of XXH pipe up to 8" (.875 wall).

I've even heard Jody say on more than one occasion that 160 amps is all you'll ever need on Carbon steel. You definitely don't need 190 amps to weld 3/16" Carbon steel.

Len

I didn't need 190 amps, I just like to go fast on fillet welds when in an easy position for it

At that amperage, on repetitive welds, I get close to "mig speed"

[Braehill]

You would need to be at Mach 3 to keep up with that heat.

Len


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[MinnesotaDave]

You would need to be at Mach 3 to keep up with that heat.

Len


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I'm not a patient man