Welding Tips and Tricks

Hello,

I've been with my current company for 6 years in March. The method of welding is TIG at my place of work. We do Land Based Turbine componets, lots of tiny welds..lots.

Recently we picked up a new component. One of the operations involve sending it out to XRAY. Out of 10 parts we ship to XRAY, 4 units are sure to come back with "inclusions". It's very frustrating. I know I am not dipping the tungsten,( I even went as far as documenting my tungsten after each weld. (Pictures). ) The tungsten I use is 2% lanth. Miller tungsten. And/or 1.5 lanth weld craft tungsten. I back gas each unit, carbide burr grind each surface, then clean it with acetone. I'm using 625 weld wire. No pulse. This is a cover weld that is covering an orbital weld. The pipe is .80 wall and .750 O.D. 625 mat.

I hope I gave enough information to go off of.

Any tips on how to lessen inclusions?

Are you certain the tungsten is large enough for the amperage you're running? Too small a tungsten will spit into the weld, even microscopically.

Was there any NDE after the orbital pass, to confirm it's the GTAW making the inclusions? I'd be suspicious, all GTAW factors controlled, that the NDE indications might not be in the GTAW pass.

Steve S

If you aren't grinding a small flat, you are likely to get inclusions. Even with 1/8" electrodes, a sharp tip will see a lot of heat (>3000C) and can drop off. The higher your amps, the larger your flat can be without arc wander and in the end you will get better penetration with a flat too.

-Sandow

3/32 lath tungsten. Measuring with my Mics about a .020 flat. I'm using a piranha grinder. Sorry should have mentioned that.

Otto Nobedder wrote:Are you certain the tungsten is large enough for the amperage you're running? Too small a tungsten will spit into the weld, even microscopically.

Was there any NDE after the orbital pass, to confirm it's the GTAW making the inclusions? I'd be suspicious, all GTAW factors controlled, that the NDE indications might not be in the GTAW pass.

Steve S

After the first pass we sent it out to xray. Came back clean. Amps are under 120 with 3/32 tungsten. I'm wondering if it's the quality of the tungsten

For what it's worth I passed x-ray with 2% lanth Miller tungsten.

Are they doing any post cleaning of the orbital parts before you are welding? Was the burr new? How big are the inclusions, where is the weld are they?

This is what I purposed at my place of work. That we put the tube in the 2g position. Put back pressure on the tube with argon. And orbital weld them with a magnatech 810 head set. This should eliminate the manual tight weld.

Anderdrome wrote:3/32 lath tungsten. Measuring with my Mics about a .020 flat. I'm using a piranha grinder. Sorry should have mentioned that.

Presuming this is DC.
Why are you using lanthiated rather than ceriated or thoriated for DC?
IMHO lanthiated works great for AC, but prefer ceriated/thoriated for DC.

dave powelson wrote:

Anderdrome wrote:3/32 lath tungsten. Measuring with my Mics about a .020 flat. I'm using a piranha grinder. Sorry should have mentioned that.

Presuming this is DC.
Why are you using lanthiated rather than ceriated or thoriated for DC?
IMHO lanthiated works great for AC, but prefer ceriated/thoriated for DC.

2% lanthinated is a pretty common all around choice. Perhaps I'm not seeing a difference at the moderate amp range I'm usually welding at but I can't tell the difference between Thoriated, Ceriated and Lanthinated for DC welding. When I overdrive them, I think ceriated splits the tip more readily then lanthanated.

I've never done a repeated arc start comparison between them and I rarely weld below 60 amps. Are you having issues with lanthinated under those conditions?

-Sandow