Hello all, hope you are all enjoying the weekend!
I'm working on a bit of late night tig practice and seem to be plagued with undercut issues. Running the following parameters:
1/8" Steel - "T" joints
3/32" Filler
3/32" Sharpened and slightly flattened at the tip 1.5% Lanth Tungsten
15 cfh argon
Running a tight arc, straight forward and backward motion, dip and step. Machine set at 100 amps, foot pedal feels 3/4 down most of the time.
Some welds look good, some have a nasty bit of undercut. Just wondering what your thoughts might be on this.
Thank you much,
Pete
- Otto Nobedder
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Weldmonger
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Joined:Thu Jan 06, 2011 11:40 pm
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Location:Near New Orleans
Working flat on the bench? Actually, I guess it's "horizontal", if one side of the tee is flat on the bench?
Why are you putting a flat on the end of the tungsten? That's an HFAC technique for aluminum, to keep the point from balling up too much or falling off. For DCEN on steel, the sharper, the better. For some of my SS work, you could tattoo with my tungsten.
This "may" contribute to the undercut, as a blunted tungsten does not direct the arc force as reliably, but I'd sooner suspect it's a timing thing in the "advance-pause-dip", keeping you from completely filling the backside of the puddle when you dip the rod. I'd think this is just a practice-and-patience issue. Are you able to see the entire puddle clearly while welding, or do you find the glare from the arc obsures the puddle a bit?
Steve S
Why are you putting a flat on the end of the tungsten? That's an HFAC technique for aluminum, to keep the point from balling up too much or falling off. For DCEN on steel, the sharper, the better. For some of my SS work, you could tattoo with my tungsten.
This "may" contribute to the undercut, as a blunted tungsten does not direct the arc force as reliably, but I'd sooner suspect it's a timing thing in the "advance-pause-dip", keeping you from completely filling the backside of the puddle when you dip the rod. I'd think this is just a practice-and-patience issue. Are you able to see the entire puddle clearly while welding, or do you find the glare from the arc obsures the puddle a bit?
Steve S
Steve,
Thanks for your advice, I'll get those points sharp! I've been working on learning both aluminum and steel and have been preparing my tungstens the same for both. I can see the puddle well, and you are right, practice, patience.
This forum and it's members are really amazing, I hope you guys know how much frustration you are saving by sharing your knowledge!
Thanks,
Pete
Thanks for your advice, I'll get those points sharp! I've been working on learning both aluminum and steel and have been preparing my tungstens the same for both. I can see the puddle well, and you are right, practice, patience.
This forum and it's members are really amazing, I hope you guys know how much frustration you are saving by sharing your knowledge!
Thanks,
Pete
RedIron881
- RedIron881
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Workhorse
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Posts:
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Joined:Fri Mar 23, 2012 9:29 am
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Location:Phoenix, AZ
Hey Pete,
Are you cleaning the steel before welding? By cleaning I mean grinding off the black carbon down to raw shinny steel. If not, that can cause undercut and a lot of headaches. It can pop and spit right onto your tungsten too. If possible, I like to grind off a good 3/4 of a inch back from the welding area on both parts. Also, look at your wire. Could have some rust build up in small amounts which would cause the some welds looking good and some not. Just run some scotch bright down the wire a few times to shine it up. Oily gloves can cause problems too. Cleanliness is Key with TIG! Hope that might help a bit. Should post some photos.
Are you cleaning the steel before welding? By cleaning I mean grinding off the black carbon down to raw shinny steel. If not, that can cause undercut and a lot of headaches. It can pop and spit right onto your tungsten too. If possible, I like to grind off a good 3/4 of a inch back from the welding area on both parts. Also, look at your wire. Could have some rust build up in small amounts which would cause the some welds looking good and some not. Just run some scotch bright down the wire a few times to shine it up. Oily gloves can cause problems too. Cleanliness is Key with TIG! Hope that might help a bit. Should post some photos.
- Otto Nobedder
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Weldmonger
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Posts:
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Joined:Thu Jan 06, 2011 11:40 pm
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Location:Near New Orleans
Pete, this is how we made it to the top of the food chain.
For 250K+ years, we've been sitting around the campfire talking about what worked and what didn't.
I don't think it's really any different now.
Steve S
For 250K+ years, we've been sitting around the campfire talking about what worked and what didn't.
I don't think it's really any different now.
Steve S
