TIG - tungsten after welding -

[Terr]

from reading about it, I understand the cone at the end should remain shiny - right? No matter what I do, it turns bluish-black after welding. This is DC welding thin SS, I have after-flow (pure argon) set to 4 sec, the flow is at 10 cu ft/hr, and it's 1/8 thoriated (red) tungsten at low amperages - 10-14 amps...

The welding otherwise is fine, and the welds look good. But the electrode does not stay shiny. Is it supposed to?

[OMS]

Terr,

I am not sure why your tungsten turns black but seems to me you need to use a smaller diameter tungsten. Using DCSP at under 20 amps with 100% argon is recommended to be done with .020” dia. tungsten. See this site for more information.

http://www.ckworldwide.com/technical_specs.pdf

See chart at bottom of page 3 for tungsten size/amp relationship.

[weldbead]

1/8 tung at 14 amps??seems way too big.. i use 3/32 tung on 1/4" mild steel at 135 amps...might try a bit of preflow too..

[Engloid]

My opinion:

No reason to go below 3/32" tungsten. I've welded .006" stainless with it, and it can be done just fine. Smaller tungsten just doesn't take the heat as well. It can more easily become contaminated or breakdown and end up in you weld.

4 seconds postflow is likely the reason that your tungsten is turning blue. You just don't have enough gas coverage on it until it cools. Also, running it as low as 10cfh, even swinging it away from the weld quickly (even with postflow still on), can cause it to not be shielded.

I absolutely NEVER weld with flow as low as 10cfh. I run 15-20 minimum.

[Terr]

Thanks - will try higher flow etc.. Question though - does the non-shininess of tungsten cause worse welds?

[David R]

I can't answer your question, but you NEED the tungsten to stay shiny because once its contaminated, it could break off in your weld and probably will not perform as well. How much stickout are you using? What size cup?

I use about 12 cfh only because if I turn it down more it causes problems. With a gas lens, I can go a little lower.

David

[Terr]

Originally Posted by David R

I can't answer your question, but you NEED the tungsten to stay shiny because once its contaminated, it could break off in your weld and probably will not perform as well. How much stickout are you using? What size cup?

I use about 12 cfh only because if I turn it down more it causes problems. With a gas lens, I can go a little lower.

I use #7 cup and a stickout of half the diameter of it approx. (or less) - as I was taught. As for the flow - I tried higher (15-20 cfh) and it seems too turbulent...

[WelderAlex]

Perhaps you should check if your cup is clean inside, it doesn't take much really to get your tungsten contaminated.

Also your post flow might be a bit too low.

Hope this helps.

[David R]

The tungsten is SO big, its probably holding the heat till its past post flow time.

Double your post flow and see if it cures the problem. I wouldn't be welding till its right.

David

[lewray]

What type of tungsten are you using...maybe I missed that earlier.

[Terr]

Originally Posted by David R

The tungsten is SO big, its probably holding the heat till its past post flow time.

Wow I just noticed that I said I was using 1/8 tungsten. Stupid me. I meant 1/16. That was a brain fart on my part. Was wondering why people said it was too big

[Engloid]

Originally Posted by Terr

Wow I just noticed that I said I was using 1/8 tungsten. Stupid me. I meant 1/16. That was a brain fart on my part. Was wondering why people said it was too big

1/16 will work, but there's really no reason to go under 3/32". You'll grind less often if you go to 3/32".

[Burning2nd]

oh oh oh

i run a .040 tungstan .040 wire set AT 50AMPs but i really run maybe half of that....

the heat depends on the thickness... but i genrally weld on .020-.049

this is all stainless encapsulated tube (wire inside)
never really used a preflow, but my postflow is about 10 seconds and im flowing at 30-25 on the regulator,

the tungsten should not discolor