[Mr. Ed]

Howdy,
New to the forum. New to tig welding. Currently just practicing with hopes of becoming proficient. Running beads on mild steel, starting to look fairly good. I put a piece of 4130 square tube on the table and used the same settings and it looked like crap. Very flat bead, frosty texture and sooty looking. I tried more amps, less amps, bigger rod (ER70S-2), travel speed and the result was the same. I did clean the tube to bright metal and wiped it with acetone before welding.

So the question is, what's different about 4130 and would anyone have recommended settings to start me off?

Thanks for any help you can offer.

Ed

[Coldman]

I'm thinking your square tube is small say 3/4 or 1". If so argon is sliding off the edges and not forming a full shield as on wider flat. Try switching to a gas lense or placing some angle against one side to allow an argon dam to form over where you are welding.


Sent using Tapatalk

[exnailpounder]

I'm thinking your square tube is small say 3/4 or 1". If so argon is sliding off the edges and not forming a full shield as on wider flat. Try switching to a gas lense or placing some angle against one side to allow an argon dam to form over where you are welding.


Sent using Tapatalk

x2

[Mr. Ed]

Thanks. I'll give that a try and report back.

[Mr. Ed]

I stood up a vertical plate behind the tube, changed to a #8 gas lense and played with a few settings. The welds look better but not particularly good. Operator technique most likely accounts for what's happening now.

Anybody out there that lives in the Vancouver, WA area and hires out as a welding instructor send me a note. I could use some instruction.

Thanks for the help.

Ed

[MarkL]

Here's the things I'd try if you haven't already:
Grind the surface, then wipe with some kind of solvent.
If you're near the open end of the tube, the contamination from inside can be drawn into the weld. Either wash the inside of the tube with some kind of solvent, or move further from the end.
Keep a piece of that flat plate handy, as soon as you get a fail on the tubing, try welding right away on the plate just to make sure nothing has changed. For example maybe the gas flow has decreased or increased and you didn't notice.

[Mr. Ed]

Ok, making progress but now having another issue. I'm getting a lot of sparks coming off the weld metal. I cleaned it up with a buffing wheel and used acetone. All that stuff flying around contaminates my tungsten, then things get worse. It doesn't happen when I'm on flat plate but does when I'm on round tube. I tried increasing the argon flow rate from 15 to 20 but it was no help. Round tube is only 1/2 " so maybe the argon is dispersing? Currently have a gas lense with a #8 cup and 2% lanthinated tungsten. 4130, .045 wall tubing.

I hired an instructor for 6 hours this weekend, his shop and equipment. It helped a great deal. No sparks flying when I was working at his place. So it's frustrating going home, setting my welder to the same settings and getting sparks.

Thanks for the help.

Ed

[Coldman]

Sparks flying is contamination from inside or outside the tube.
If its outside contamination try a No.5 gas lense cup and keep turning up the gas until it stops.
If its inside the pipe you have dirt or rust coming through. You have to find a way of cleaning the inside or get new steel.

There is still the possibility of air drawing into your gas hose somewhere between the argon cylinder and the torch. Check everything.

[MarkL]

It doesn't happen when I'm on flat plate but does when I'm on round tube.

The problems I've had with tubing are:
1. Contamination inside tube, could be cutting oil, rust, whatever. Use hot water and soap if you don't have a solvent wash.
2. You might need to purge the inside of the tube. Heating the tube can cause air to come through the joint from inside the tube, kind of like a chimney. If you don't have a purge line, you can push some aluminum foil into both pieces of tube about an inch or two, so it creates a small cavity inside the tube. Then start your argon flowing without striking and arc and hold it against the joint to try to displace the air inside with argon. Do that a few times, then start welding right away.

[bruce991]

Check for a leak on your argon hose and fittings at both ends. Are you running about 20cfh?

[Mr. Ed]

I think I've found the problem. I forgot to turn on the argon a while back and got a bunch of sparks. After turning the argon on I continued to get sparks. A previous reply suggested changing cup size so I tried that. When I did I found all kinds of crap caked on the inside of the cup. Looked like my mig welder. As soon as I cleaned all that out the sparking stopped.

Thanks for all the suggestions/help.

Ed

[Oscar]

Yup, no argon will do that.