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Up Topic Welding Industry / General Welding Discussion / GMAW-P 4G- How the blzes does one get that bead to lay flat?
- - By Bowler_Hat (**) Date 03-11-2016 16:53
Hey All,

I'm not bald, but I'm getting there (sparks...not pulling hairs).

We're trying to captalize on our Lincoln POWERMIG 350 MP and it's GMAW-P abilities. But for the life of me and every other welder in house, we can get a bead to lay flat in the 3G or 4G position.

I've given the staff at lincoln a call, and we haven't quite figured out what to do. Was comin' here to see if anyone had a direction to point towards to get to where we want to be.

I've been dialing up the WFS and down one value at a time, same with Trim and Arc Control. I haven't found a nice combination to make these things wet out and not sag in the middle.

Any thoughts?

Cheers!
Parent - By Lawrence (*****) Date 03-11-2016 17:46 Edited 03-11-2016 17:48
I'll assume you are talking about steel here.

I have seen PowerMigs run vertical with .045 pretty well, however the tradeoff is in travel speed.  It will be very slow.

I've never seen a 350P do good verts or overhead fillets or CJP grooves in structural thicknesses. And I used them for 9 years.

Now I will say that Lincoln has come a long way with GMAWP and makes constant updates, so maybe they will have some answers for you, but I'm skeptical that GMAWP can weld structural steel out of position at even half the productivity rate of gas shielded FCAW.

My opinion of GMAWP for D1 structural is that in some *limited* scenarios, you can see a benefit over traditional Spray or MCAW.

1. In automated/mechanized systems where high travel speeds are needed and exceptional control is taken in fit-up and fixturing.
2. When exact weld sizing is important in fillets 1/4" and smaller.
3. Both 1 & 2 are predicated on the work being placed in the flat or horizontal welding positions.
4. Production pipe welding, where there is a high level of process control.

Say a little more about the vintage of your PowerMigs, There may be some weld sets (pulse programs) in there that you haven't tried (Rapid Arc & Precision Pulse) Some of them have some wave form adjustments beyond "trim" called "Ultimarc,"  These subroutines are more subtle but can sometimes have an impact on profile, especially if there is some mill scale involved.

Physics don't change because of pulsation... A spray bead, even a lower currents (where you risk LOF) is still going to have a wider, wetter puddle that is more difficult to control.  This is why the vertical GMAWP that I've experienced is questionable at best... It's slow because lower current levels are needed to keep a controllable puddle, and because of the lower current level it's debatable that you are having any advantage over short circuiting transfer...  Defiantly behind FCAW for efficiency, quality and productivity..
Parent - By pipewelder_1999 (****) Date 03-11-2016 19:28
There it's a physical limit too how much wire can be melted in a position other than flat. Vertical has an advantage vs overhead in the fact that uphill progression is much less prone to fusion type discontinuities.

Pure overhead can be a challenge as there must be enough arc force to propel the metal against gravity and yet stay cold enough to reduce the time the metal is molten.

Pulse Transfer as a fix for difficulties welding out of position is somewhat hype in my opinion. Processes with Slag seem to provide more consistent results as far as bead appearance goes. Running 200 plus amps overhead with 71T1 is no big deal. Getting to that deposition rate with GMAW has been impossible for me to do but GMAW is by no means a strong point of mine.

I may play next week and see what can happen.
Parent - - By TimGary (****) Date 03-11-2016 20:47
With Miller's Accu-Pulse, I can run .045 4F, with 90/10 gas and ER70S-3 wire, at 400 IPM WFS, 40 Arc Adjust and 30 Arc Control.
4G cap at 300 WFS, 40 Arc Adjust and 25 Arc Control.
The convexity on the fillet is good. Any more WFS or too slow travel speed humps it up though.
Have to use a weave on the OVH cap to keep the convexity down. Again too much wire or not enough travel speed causes issues. Harder to control an OVH cap than in the bevel or with a fillet.
I finally decided not to approve OVH pulse grooves for production, due to too high of a re-work probability for an ordinary Joe Welder.
Fillets are not a problem.

Accu-Pulse is similar to Lincoln's Rapid-Arc.
Not sure what waveforms your 350 MP has.

Tim
Parent - By pipewelder_1999 (****) Date 03-11-2016 21:44
My physical limit has been about 250-260 IPM in short circuit with .035 so it does look like there is some advantage with pulse, sign me up for some of that "special gas" and pulsing stuff!
Up Topic Welding Industry / General Welding Discussion / GMAW-P 4G- How the blzes does one get that bead to lay flat?

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