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Old 07-21-2013, 11:57 PM
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Default Tig on Stainless Steel (practice welds)

I decided to finally use one of my large gas lens things today. Never tried one before. All I have now is a #12 cup for it and it may be too large but, hey, make do huh?

So, having issues with stainless, since I started this last year, I notice things improved with the gas lens. Still, weld beads turn out grey as usual except when I go back over a previous bead and just push the puddle around. Then I get the pretty little salmon, gold and some blue colors everyone talks about.


This first picture shows two beads. One is the first bead as it turned out and is the grey bead. On top of it is where I just came back later and wet it and pushed the puddle around. No filler. I was at about 100 amps, 3/32" 2% Thoriated tung, 18cfh argon flow.

What is the reason I get the two different results?
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Old 07-22-2013, 12:00 AM
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I am just trying to guess but I think my issues may be one or more of the following:

- I am allowing my filler tip to become contaminated
- I linger too long when I am using filler and over heating the weld
- I may be growing my arc length too much as I add filler trying not to dip the tungsten in the puddle



Here are some more shots of similar results on the same bar I was welding on. This is just different views of that same weld.
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Old 07-22-2013, 12:02 AM
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And here are shots of another weld bead. Same thing. Grey bead at first then better color once I go back over it with torch.

I played with amps a lot and was at about 65 when I started out. That was too low for this thick 1" bar of stainless. So I bumped it to 130 amps and used the remote to lower it a few percent at a time. I think about 115 to 120amps is where I settled.

There are other beads that I ran but they were all grey until I brushed them. No photos of those.
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Old 07-22-2013, 09:32 AM
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Smile Gas Coverage & Heat Control..

Stainless is really sensitive to gas coverage and heat control...

very easy to lose gas coverage while still hot and get discoloration...

plus in your case.. you have no pedal.. so no tapering the heat of for crater control and more danger of overcooking your bead.. overcooking will get you carbide precipitation.. which is not only ugly.. it separates the alloy which weakens the weld metal and leaves it prone to rust..

here is a vid of gas lenses (not a great vid.. but usefull nonetheless)

http://www.youtube.com/watch?v=v2ePmA3VKbc

These are pretty good..

http://www.youtube.com/watch?v=mzJR_qkO9wo

http://www.youtube.com/watch?v=Dz2ZmA4O5SQ
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Old 07-22-2013, 11:06 AM
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The rainbow color effect is normal and let you know you are getting
adequate shielding gas; the matte grey color is clearly inadequate
shielding gas. As mentioned over heating stainless will create chromium
carbide precipitation which can cause cracking at the toes of the
weld rusting and generally poor and weak welds.
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Old 07-22-2013, 12:01 PM
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Quote:
Originally Posted by H80N View Post
Stainless is really sensitive to gas coverage and heat control...

very easy to lose gas coverage while still hot and get discoloration...

plus in your case.. you have no pedal.. so no tapering the heat of for crater control and more danger of overcooking your bead.. overcooking will get you carbide precipitation.. which is not only ugly.. it separates the alloy which weakens the weld metal and leaves it prone to rust..

here is a vid of gas lenses (not a great vid.. but usefull nonetheless)

http://www.youtube.com/watch?v=v2ePmA3VKbc

These are pretty good..

http://www.youtube.com/watch?v=mzJR_qkO9wo

http://www.youtube.com/watch?v=Dz2ZmA4O5SQ
I actually just watched three of Mr. Tig's stainless videos the other night just before I fired up the tig. Pretty informative he is. And I have watched all of Jody's videos multiple times. These are actually why I went ahead and tried one of my gas lenses.


Quote:
Originally Posted by Shade Tree Welder View Post
The rainbow color effect is normal and let you know you are getting adequate shielding gas; the matte grey color is clearly inadequate shielding gas. As mentioned over heating stainless will create chromium carbide precipitation which can cause cracking at the toes of the weld rusting and generally poor and weak welds.
What changes though when I use filler versus not using it? Those welds were done just minutes apart, without amp adjustment and no change in cup or gas flow settings.

If I sit and run a bead with filler I get a grey bead. I go back over it and wet it and just push it around a little I get the prettier colors.

Something I am doing when I use filler is screwing me up.

I know I can't taper off because I have no foot pedal control and it causes the end to crater and look burnt. I also can't hold the torch at the end of the weld for shielding because the HF throws lightening bolts and won't extinguish the arc if I am too close to the work.

If I flick the arc off quickly and go back to shielding the weld it lights back up again. I know my torch switch will allow me to cut the HF off but I don't have that one built yet and I took the RCCS off.
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Old 07-22-2013, 03:55 PM
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Default Another prcatice day

So I was off work today and fired up the tig again.

Same thing, gas lens with #12 cup, 1/16" 308L filler.

This time I lowered the amps to about 85 and turned up the flow just a tad to maybe 20cfh.

I also decreased my tungsten stick out to about 1/4". I made sure to keep a tight arc, clean tungsten and a better torch angle.

I cleaned the metal surface a little better this time.

I got much better results.

The first pic shows my first bead and it was grey. I made changes above and got the better results afterward.
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Old 07-22-2013, 03:56 PM
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Here is another.

Second pic shows where I just melted a puddle and pushing.
All I did here was strike an arc and push a puddle. No filler.

Pics are from opposite angle. Both beads were ran from my right to my left.
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Old 07-22-2013, 05:41 PM
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practice practice practice....

and I will refer you back to..

http://shopfloortalk.com/forums/show...696#post559696

you will never have the fine control of a dedicated machine with your present setup...

but the switch and more practice skillbuilding will help you a bunch IMHO
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  #10  
Old 07-22-2013, 06:07 PM
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Quote:
Originally Posted by H80N View Post
practice practice practice....

and I will refer you back to..

http://shopfloortalk.com/forums/show...696#post559696

you will never have the fine control of a dedicated machine with your present setup...

but the switch and more practice skill building will help you a bunch IMHO
That is the plan sir!
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