Tig welding steel?

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Posted (edited)

I usually only use my Tig for Aluminum but today I thought I would use it on my door latches that I am making for the Kitfox.  Take a look at the welds if you can see them. I am wondering why the back side of the steel is bubbling so so bad? Am I using to much heat? or not pulsing my foot enough? I see this everytime I tig welded steel. Its all 4130 and I am using ER80 filler any thoughts thanks.

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Edited by TJay

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Posted

The backside is oxidizing.  You can use a twin regulator/flowmeter to back purge welds like that.  https://www.youtube.com/watch?v=-uoxKZtqXrA   If you dig around on Jody's site you'll find MUCH simpler purge chambers he's built.   I got a separate bottle of argon just for back purge on stainless.  

Now, having said all that they used to pay me to mig and stick weld but I major suck at Tig.  For starters, I don't have a decent table to work from.  Every time I set up a weld it's just kind of half assed you know?  I need more practice. 

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Posted

I’m not expert but I think you have to move faster. Amperage is probably about right. 

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Posted

What gas are you using?  What diameter tungsten and filler wire?  Welding steel you really don't need all the fancy pulsing etc but it can make it a bit easier. 

Like Sed said.. move faster and maybe a few less amps.  Tungsten is nice and sharp?  I have switched over to using Layzr tungsten for both steel and aluminum welding.  One and done and it really does work very nice.  We switched our entire weld shop here over to it after I played with it at home a bit.

For most of the welding I do on 4130 tubing I use 1/16th tungsten and .045 er70S2 rod.  No need to run ER80 and that will be more prone to cracking as well.  It does not flow quite as nice either.

:BC:

 

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Posted

Depending on how fussy you are about the appearance of the welds inside you could get a piece of non conductive carbon rod to fit perfectly inside of the pipe shell you are welding on and control exposure to oxygen and give any melt thru essentially no place to go. Coming up with a place to get a piece of carbon rod to fit exactly inside and completely compliment the radius will be a perhaps bigger challenge than it is worth. 

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Posted

Knock the mill scale off first as well.  Looks like your getting that on the back side along with the melt through / penetration.  Smaller wire diameter will take less heat to melt it and form a nice tight puddle / bead.  .035 wire will really make your welds look like a jeweler did them if your running 1/16" or even .040" tungsten as well.  Use a Dremel and sand the parts then paint them and they will look perfect!

:BC:

 

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Posted

Running the really small tungsten think there .040 with small filler, think I just need more practice moving faster. I really like Tig welding so clean and quite while welding. Running pure Argon. I will look into those Layzr as well.

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Posted (edited)

Maybe I can round up some parts for you to practice on?  I've got some that look like they were bubble-gummed together.  Ha!  EDMO

Edited by EDMO
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Posted

The "bubbling" appears to be weld over-penatration. As mentioned you could try to backpurge but I would suspect your tungsten is too large a diameter as is your filler rod as mentioned also. The amperage may be a hair too high and you may be dwelling. With thin wall steel and stainless steel you need to be moving along. I have made a lot of sugary stainless welds and a lot of overpenatrated welds with TIG in the past. None were critical but that is my $.02. 

I know the post is old, but adding observation and suggestion for future viewers in need of help.

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Posted

And here I am considering buying a TIG and getting rid of my torches.

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