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Up Topic Welding Industry / General Welding Discussion / Root bends cracking in weld A36 GMAW Spray
- - By SeeJeepGo (*) Date 02-15-2019 14:48 Edited 02-15-2019 17:29
I had one of the welders run some 1G single V groove coupons for a GMAW solid wire spray transfer Welder Qualification test i need to have several people do. A36 3/8" coupons, 45deg groove, 1/4" Root gap, w a 1/4"x1 backer, [.035"] 70s6 wire, 98/2 (AO2) gas 40 CFH and ran it at 27V / 450 IPM which resulted in around 200-215 Amps.

We did everything together, I saw the tacked up coupon, watched him do the passes and the finished weld looked good had just enough reinforcement and no undercut, I told him how to prep the strips. I bent them in a new bottom ejection jig that I made a couple weeks ago using nice rollers and a new plunger because the old one was all beat up. It has a 1.5" plunger and rollers are spaced 2.375 apart like D1.1 shows.


The face bend looks fine w 1 tiny mark along the edge. but the root bend tore open.

The root pass he made was kinda wide and touched both bevel roots. maybe it wasnt enough on that one side....Ok So I had him do another
with the root passes one stringer along the root of each bevel face to ensure good root pen. that left a slight space in the middle so he did a center pass to tie it all together before the fills. The bend tests got similar results.
[EDIT: i realized i didnt add this photo earlier]
Face was good, but root opened right down the middle. when i saw that separation i thought that maybe he didnt get good fusion because the narrow center root. (This tear is exagerated . i squished it more in a vise to open it up so i could see inside it)

Third times the charm? He had to go work on something else and I decided I'll weld one up myself.
Did 2 root passes that overlaped nice and then filled and capped with 3 additional passes. I moved a lil quicker than he was (around 14 or 15 IPM vs his 11 or 12) I also did the first 3 passes without much cooling off time. He had waited in between each and even used blew some air across the final weld to cool it off.   maybe it got brittle??? anyway, I got even weirder results. My face bend was good.


Root was a total failure, it snapped before it even bent!

I thought maybe i wasn't paying attention and something got weird or jammed in the jig? so i cut a second strip out of the remainder center section. It also had 2 tears open up in the middle:


would love some advise from the experts to help figure out why I'm getting failures like this. The only thing i really wasnt sure about was the coupons themselves. They were already precut leftovers from past tests. but even if they were cut and oriented against the grain/rolling direction..... how / why woudl that effect the weld itself? if the failure was occurring in the HAZ or base then maybe...
any suggestions are welcome. Thanks in advance.
Parent - - By jwright650 (*****) Date 02-15-2019 16:29
Are the silicon islands being cleaned off?
Parent - By SeeJeepGo (*) Date 02-15-2019 17:13
yes, after each pass some light chip and scrap and wire brush
Parent - - By jwright650 (*****) Date 02-15-2019 16:32
Is the failure opening up at the bevel to backing interface? Just wondering if the point is being completely consumed  or not.
Parent - By SeeJeepGo (*) Date 02-15-2019 17:19
The first fail had 2 tears one 3/16" one 1/4" long along both sides of the weld (the root of each bevel). this I assumed was due to a single wider root pass that probably did not fully consume both bevel roots entirely. The subsequent roots were made smaller, one on each bevel root. Those had tears down the middle of the weld, not along the edges.
Parent - - By Steelslinger (**) Date 02-15-2019 16:47
Just judging by the pictures, which is iffy at best, it looks to me to be lack of fusion, at least in the one that broke fully.

Try going with a narrower root opening. I usually advise our guys to run closer to the 3/16" due to the narrow tapered nature of GMAW Spray with Argon/Oxygen blends (We use 95/5). Its a pretty tight cone of a weld nugget. Or run wider and do two root passes instead of one.
Parent - By SeeJeepGo (*) Date 02-15-2019 17:21
the first one, as mentioned above, i agree LOF at the weld interface, the root of the bevel did not fuse 100% and it tore along that edge. but the subsequent ones had failures in the middle of the weld metal. so LOF among the weld layers?
Parent - - By Lawrence (*****) Date 02-15-2019 16:51
Here are a couple of things to think about.

Was the backing strip absolutely tight/flush?  even a small gap can blow a test.   Clamps while tacking can solve that one.

98/2  Argon/Oxygen gives a nice spray transfer arc with GMAW and (I'm assuming) .035  ER70S-6 solid wire.  You can see that needle sharp end of the electrode wire and the bell shaped arc very clearly.

Having said that, the Ar/Oxy mixes also spray a lower voltage than Ar/Co2 mixes and this can cause some confusion and difficulty.  Let me explain a bit more.

To get that root fusion on each bevel edge you need to do one of two things... 

1 make a root opening tight enough to get good fusion in a single pass.  or
2  Make a root opening wide enough to accommodate a split root.

Either way:  With Argon/Oxygen mixes and weld test assemblies, in my opinion, it is critical to use the LOWEST ARC VOLTAGE VALUE possible and still have a good spray transfer. 

Why is that important Lar?   I'm so glad you asked!    As the voltage increases, the arc length increases, and so does the width of the bell shaped arc.  The arc spreads out the heat and can bridge the fusion along the root/toe of your test assembly and cause defects exactly like the ones we are seeing here.    Furthermore:  You may notice that when you prepare your test assemblies to ground *brite metal* that the arc length is longer and the arc sound is quieter than you normally experience when welding over typical steel with some mill scale....... 

So what do I do about all that Lar?    Easy stuff....  Grind some steel to brite metal and make a weld.  Set your WFS to get about 230 amps and start about 26 volts.  Look at the arc length.  If it is 1/8" or more, reduce volts by 1/2 volt increments until you see spatter, then increase 1/2 volt and try again.   Don't mind a little crackle sound.  As long as there is no spatter you want to keep the arc as short as you can get it.

Don't whip!   Don't weave !   Just a straight root pass that goes in like caulking.

A row of dimes is for E6010  not GMAW!   Never whip spray GMAW

For the split root focus that short arc on each beveled edge without touching the other.  You should be able to literally see the fusion happening.  The root pass should be rather small. No larger in volume than a 5/16" fillet, and probably closer to 1/4.

If a single pass root, both bevel edges must be equally fused, which means they must be close enough together to do it.  I like a 3/16" root opening for this.

Also:   I know this is more than you asked for....   .045 is a much more efficient electrode wire for spray GMAW.  It will carry more current and produce a bit wider puddle at the root in flat and horizontal position that is a bit more controllable than you can get with .035 at a similar amperage.......... 

Frankly if I were in the flat position, I would want to run that test assembly at nothing less than 250 amps.  But you may be bound by a WPS that does not allow for that.
Parent - - By SeeJeepGo (*) Date 02-15-2019 17:54
Was the backing strip absolutely tight/flush?
YUP clamped before tacking

(I'm assuming) .035  ER70S-6
YUP i forgot to add that.... edited.

1 make a root opening tight enough to get good fusion in a single pass.  or
2  Make a root opening wide enough to accommodate a split root.
Was going by the 1/4" ROOT gap listed in D1.1 Fig 4.20. I know there is a tolerance listed in 3.3 for that groove [BU2a-GF] but I try and stick with the clause 4 specs for testing. But i will def try a sample with a 3/16" root to see.

I will double check parameters based on your adjustment process. I DID go and look at hte mfg spec page for this wire (Washington Alloy) and they actually list a surprisingly low Voltage compared to other wire specs ive looked at.
"Spray 0.035  WFS: 320-600  AMPS: 160-300  VOLTS: 23-26 TRAVEL:11-22 IPM"
so.... i guess ill see what a low voltage is like. ive been happy around 26-27\

Just a straight root pass that goes in like caulking.
Straight and smooth like a robot, i hold my angle and slide like im on rails.... love me some spray metal caulking

nothing less than 250 amps im sure with .045 that would be easy, not so sure with .035. and like i mentioned earlier the attempt is to keep one wire size in a machine to make it more dual use.

thanks for all the input.
Parent - - By 803056 (*****) Date 02-15-2019 21:56 Edited 02-15-2019 22:03
I've qualified a lot of welders over the years on carbon steel using spray transfer with a 1/4 inch root opening. Most welders pass without too much difficulty if there is no root face and they use a slight weave to tie in the beveled edge.

Since you mentioned spray it is a safe assumption the test position is flat. The welder should use a backhand technique rather than a forehand (push) technique.

As mentioned, make sure the backing is tight against the underside of the test plates. I put slight bow into the backing, with the bow toward the test plates. The tack welds should be on the ends of the test plates, no tacks near mid-length.

The weave consists of a slight side to side motion, directing the arc toward the edge of the bevel, enough to fuse the edge of the bevels. Just running the arc down the middle of the groove, allowing the weld pool to "flow" to the edges of the bevel, will often result in incomplete fusion.

A 1/4-inch root is too wide to weld it with a single pass stringer and too narrow for two stringers. A weave using 0.035 or even 0.045-inch diameter electrode is the secret. At least, it works for me. The weave has to be tight like the letter "Z". Advancing too fast will leave a little incomplete fusion with each zig and zag.

Al
Parent - - By SeeJeepGo (*) Date 02-19-2019 18:50
Al,
Thanks for the info. I've seen conflicting posts regarding which method to use with spray transfer so when you mentioned drag I figured OK why not try that AL says so.... :-)
I also adjusted my volts down a touch to 26.0, turned my wire speed up to 535 and adjusted my stickout to keep the amps up. I was impressed with the look of my root pass. I practiced that dragging Z move (like a sawtooth N since i was doing it from left to right) around 19 IPM and it was smooth and cleaner with less silicon islands than before.


I did the root, then 2 fills and 2 cover passes. I thought about switching back to push for the covers but ended up just sticking with it to be consistent for this sample.

cut out my straps and bent them both root face because thats where ive been having problems.
 
I noticed that I did not get complete fusion along that bevel edge, esp in that one strap. but at least it didn't break in half or tear open. I guess some more practice and refine the drag method will help.
Thanks for the feedback and help.
Parent - By 803056 (*****) Date 02-19-2019 19:29
Tighten up on the side to side weave on the root, i.e., don't advance forward quite as much.

Good luck. Looks better for sure!

Al
Parent - - By SeeJeepGo (*) Date 02-19-2019 19:31
I also decide to etch one of the edges to see what the pen looked like. this is from the drag sample

its clear that the bevel edge is not fully consumed in the root.
Parent - By 803056 (*****) Date 02-19-2019 19:46
Need some weave. It's like Cowbell, there's never enough Cowbell in the music (from SNL)!

Al
Parent - - By Jim Hughes (***) Date 02-16-2019 12:20
SeeJeepGo
I noticed you mentioned Washington Alloy. We have similar problems with them. Have you used them in the past? Have you ever had any issues with their product?  Just trying to cover every base.
Parent - - By SeeJeepGo (*) Date 02-19-2019 13:02
We've been using the WA brand for years but never with the Spray Transfer process just Short Circuit.
Parent - By Jarhead1 (**) Date 02-19-2019 15:38
Material looks very hard?
- - By SeeJeepGo (*) Date 02-22-2019 18:50
As an update.... I did a few more samples with some improvement but still not 100%satisfied with bend results on the root side. Could the 98/2 just be limiting the amount of weld energy with the narrow root and the fact that with .035 i just cant get the higher amps?

So I decided to try a different approach. I switched machines to a miller 350p that had a tank of 90/10 on it. I ignored the pulse programs and just went straight GMAW. I was so accustomed to the smoother hiss welding with the 98/2 oxy that the harsher sounds and feel of the 90/10 took a min to adjust to. Maybe I'm still off on the ideal parameters, but i ran a test to see. I did this with a 10 deg push angle, 26V and 525 WFS.  around 225 amps, less on the top covers. The root was a lil less than 1/4" opening, so i took Al's advice and did a tight side to side motion to capture the bevel edges. After that the fills and cover were quick and smooth.
ROOT on left, FACE on right.


IDK maybe ill stick to 90/10 and try and fine tune the settings and give someone else a test run to see if they can make it happen. Since this is a PreQual joint I can write a new WPS for this gas and settings and then use that to run welder qual. Since shielding gas is not an essential variable for quals the welders aren't restricted from using 98/2 once they pass the test using 90/10 as long as there is a WPS for 98/2

ahhh TGIF
Parent - By 803056 (*****) Date 02-22-2019 19:48
They passed! The goal was met.

Al
Parent - - By Lawrence (*****) Date 02-23-2019 18:36 Edited 02-25-2019 13:45
A couple of thoughts (and a long standing dig/debate at Al)

Why would you consider going back to a weld gas for production that you can’t make a quality weld with under the most ideal conditions of a test lab?

Also...   The comforting “hiss” of your 98/2 welding gas in my opinion is the signal of exactly why your first set of tests failed in the first place.

You “Know” that you can’t make a good weld with 98/2.  

So what if you're certified, and so what if weld gas is not an essential variable?  

Until you get your Ar/Oxy process under control, (and you can control it with ease)   I don’t see how you could use it in production and sleep at night.

While there are several schools of thought on spray GMAW, it is a fact that an excessively long arc, caused by high voltage will make that hissing sound.   A constant crackle WITH NO SPATTER is the best sound indicator of a good GMAW spray weld.   If the crackle produces spatter, increase volts in 1/2 volt increments till you have crackle and no spatter....  This simple technique will work with argon/oxygen or again/Co2 gas.

Hopefully your experience with the 90/10 helps add some credibility to the blather above from me.

Also.... Running GMAW with a drag angle in a laboratory scenerio or on a robot can indeed slightly increase the penetration profile. But, with manual production welding it usually backfires.   Why pass a performance qualification test with a technique that will not be practical to perform in production?

The fact of the matter is that Lincoln, Miller, Hobart, NCR, AWS, all train and recommend  GMAW spray transfer with a push travel angle.   A simple D1.1 flat or horizontal plate test assembly can be completed with a push travel angle for the root and fill passes.   

I see no wisdom in performance qualification that does not at least attempt to mimic production conditions when possible.
Parent - - By SeeJeepGo (*) Date 02-26-2019 16:54 Edited 02-26-2019 17:14
Lawrence, I agree with the ideas behind everything you stated. I plan on figuring out the necessary adjustments to make it work properly on my end. That's why i'm doing these samples and tests, and why i'm posting results on here for feedback and critiquing.

I just used your method to find a voltage to work with using 98/2. Ended up lower at 24V with a lower wire speed at 465. Did a series of quick fillet tests and achieved penetration down through the root, although the roots ended up on the smaller side. less than 1/4, closer to 3/16 at times so I did more passes to see how that worked. got up to 5/16 maybe 3/8 in spots. I did switch back to Pushing.


Just finished a sample groove coupon and will cut and bend after cools a little. I found that I couldn't get above 235 amps and that was usually at the early part of the weld, as I progressed it would drop to 220, 215 close to 200 at the end. I also think the crackling increased due to this but not enough to create more than just a couple little spatter balls. [I use my phone to video record the XMT display so I can rewatch it and both time the welding and see the amps/volt readout]
I felt like the arc was struggling past the 3/4 mark, maybe the contact tip was overheating or the wire wasnt feeding as smoothly. idk.

Ill post those pics later. thanks for the info everyone it's what makes this such a great forum.
Parent - - By Lawrence (*****) Date 02-26-2019 18:47 Edited 02-26-2019 19:12
Current decreases as CTWD or Stick-out increases....   This can happen by just having a longer vertical stickout or it can happen if you turn your wrist at the end of the weld and increase the push angle...  Either way... The current goes down and that reduces the likelihood of good fusion at the root.   The current is changing because your gun angle is changing  :)

You really want greater current to simplify the weld for this test assembly.     If your trials are to develop what is best for a future WPS...   I would recommend setting your WFS to get a 250-270 Amp arc with a stickout of 5/8" and your contact tip recessed 1/8" inside the nozzle.    Just keep doing trials like you are doing while at the same time making sure you are improving the consistency of your gun angle for the full length of the weld.

Once you have consistent current (250-270A) with a minimum voltage spatter free weld....(When you get your WFS set to get that correct amperage, you may need to increase a half volt)    Only then try another test coupon.

The shorter arc will help keep the weld pool sized appropriately...     When the push angle is too great you will see a teardrop shaped puddle with a crater defect at the terminations,  and V-shaped ripples in the weld..  When the gun angle is proper 10--15 degree push you will see a puddle that is *almost* round and ripples that are much less V-shaped.

With this technique you should be able to make 1/4 & 5/16" fillets that look just like caulking... No whipping, no weaving.. Just a push with the electrode wire at the leading edge of the puddle..  You will see the Arc-Force digging away at the root as you go if you keep your head properly positioned...  There is literally no chance to have a lack of fusion on a fillet break when these simple steps are understood and followed....   The only difference between the quarter inch and the 5/16 inch fillet is the travel speed when you get this down.

It just takes a little coaching..   Once you understand why you're doing what you're doing, your comfort level is going to be really so much better.

Let me also say...  Al  (803056) is smarter and better than me in every way...   I think this topic of GMAW spray transfer and gun angles is the only thing I've disagreed with him about in the 20+ years we have been friends.....    I debate here for the sheer joy of rebelling against my Master.

Edit:

Either gas is perfectly suitable for mild steel and AWS D1.1 test assemblies.  Once you get those process control steps sorted, you can choose the one you think works best for the work you do... Some people think the Co2 mixes work better when heavy plate with mill scale is involved, but let your own trials be the deciding factor, rather than some salesman.
Parent - By SeeJeepGo (*) Date 02-26-2019 20:17
"Current decreases as CTWD or Stick-out increases....   This can happen by just having a longer vertical stickout or it can happen if you turn your wrist at the end of the weld and increase the push angle... "

I preach (teach) this on the shop floor.

"The current is changing because your gun angle is changing  :)"

I should take a pic of my setup for testing. I have a piece of aluminum channel to use as a guide/slide rest. I'm able to hold the gun and slide the whole length consistently. I can adj ctwd with a small movement of my hand under the gun against the alum and can pivot it slightly to adj angle as I get started. I feel im exceeding the normal conditions for 'manual' welding to try and keep this test consistent.
I have my CTWD at 5/8" and even keep the tip flush for the roots so i can be sure im in there without excessive stickout. If I push it closer, i overheat the tip but i can try again. I know 250-270 is the target i just havnt been able to see that achieved.
Parent - By jwright650 (*****) Date 02-26-2019 19:12
Thank you for posting the pics...the saying..."a picture is worth a thousand words"...is true.
These are great pics too, crisp and clear with good light.
Parent - - By SeeJeepGo (*) Date 02-26-2019 19:54
Here are the promised pics from the bends.
I did them all ROOT face bends cause thats been the problem area. Even the 2" center left over strap.



there was no visible LOF lines along the bevel toe edge after grinding the backer. some tiny pinholesmaybe from porosity or spatter? those caused the discontinuities <1/32" pinholes. There was one corner crack 1/4" and on the same an 1/8" disc. On the other a few small <1/32 or just 1/32 so i would think these acceptable per the criteria, obv with a good face bend included.  That corner crack is in the middle area so im assuming from where the 2 root welds overlapped. same issue we had prior. i guess i should try another w a larger single root, but i feel like ive been down that road already.
Parent - - By Newt18 (*) Date 03-11-2019 15:39
Good morning all. I thought this thread has been very intriguing. We perform a lot of welder qualifications on steel, SS, and aluminum with multiple filler materials, wire sizes and shielding gases. We use 98/2 gas for SS welding and thought it would be fun to play with.
        Over the weekend I was able to run a welder qualification weldment using 98/2, .035 L-56 filler, on a Lincoln 455 powerwave, with standard constant voltage.
       
         Standard material prep.

         Two root passes. 575 wfs, 24 volts, 225 amps. All other passes were below, but above 200 amps per machine readout. Forehand technique. 5 degree travel angle max. Stickout past nozzle, .500 to .625.

         3 fill passes.         575 wfs, 25.5 volts,  travel angle 10 degrees max, stickout .750 max. 400 F interpass temp.

         2 cover passes.    500 wfs, 26 volts, travel angle same, stickout same.

         The test was a pass. Pretty typical discontinuities we see when using a 02 shielding mix. The larger discontinuity on the root bend goes back to the first root pass. In the pic of the first root I had a large piece of spatter and good of cleaned it out better. 

     Hope you enjoy.
Parent - - By Newt18 (*) Date 03-11-2019 15:44
Having problems with the pics. May have to come back to it.
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Parent - - By Lawrence (*****) Date 03-11-2019 21:00
Great fitup on the assembly.. Nice and tight  :)

Bends look good too... Nice prep

Now for fun questions:::  ??

You ran different parameters for the root, fill and cover passes.

If you were doing a production CJP on the shop floor, would you set your machine 3 times to make a weld ?

Not really calling you out...   Just asking for fun...

I bet that whole assembly would have gone just fine with the 24-ish volts you used on the first passes.   Cover passes are always the ones more subject to undercut defects and increased voltage just makes that more likely...  What other benefit does increasing the voltage give you on a cover pass?    That's a real question...  I'm trying to think of a reason you might want to increase the volts as you go.
Parent - - By Newt18 (*) Date 03-11-2019 21:59
Hi Lawrence! You are one of my welding hero's by the way!!
          Yes, I agree with you that could be completed with one setting throughout. We want the welders to be comfortable adjusting equipment following wps's and instructions. Its just a training method. Our production wps's are one range, some repair wps's have multiple ranges.
      More tomorrow.

      Thanks.
Parent - - By Lawrence (*****) Date 03-11-2019 23:14
Hey.

If Jonny wants to turn the knob, that’s fine by me :)

Our Powerwaves are locked to the WPS’s !

It it’s in the range, the guy pulling the trigger is the craftsman.
Parent - - By Newt18 (*) Date 03-12-2019 03:31
Hi all. To the Op,  you mentioned  maybe working more with the C10. I would recommend also trying  92 Argon/8 C02 and the 95 Argon/5 02. Both work well on carbon steel.
Parent - By Newt18 (*) Date 03-12-2019 04:14
Hi Lawrence. 95% of our  semiautomatic weld power sources are  Miller452s with  Miller Axcess machines on all robotic equipment. I love my powerwave! The majority of our production wps's are single  range parameters. We have numerous parts that require  multiple wps's though , even with multiple operations. Our welders also perform fillet weld break tests and macroetches too. Travel speed, travel angle, gun angle, stickout, are all  problematic.  Multiple range  parameters on the CJP welder qualifications help reinforce training methodology. Man, I am really rambling now.
Parent - By SeeJeepGo (*) Date 03-13-2019 17:56
do you see much difference on 92/8 vs 90/10 Co2 ?
Parent - - By SeeJeepGo (*) Date 03-13-2019 17:55
thanks for adding to this thread! I enjoyed seeing some comparisons. I did finally get some guys to pass this test and ended up increasing the WFS more than i had previously, and finding a comfy voltage to work with (which was up around 27 again) Anyway, maintaining the AMPS as was previously mentioned was key to getting complete root fusion. Once we were able to do that around 250-260 amps, everything worked out. It was frustrating because you had to do the root pass perfect, but didnt know until all the other passes, cooling, cutting, grinding, etc etc and finally bending was done too.

And Lawrence, thanks for your input. To your question about voltage, the only thing i can think is that increasing the voltage a little, increases the arc cone size/width which should flatten the bead for cover passes... providing you keep on the lookout for undercut of course.
thanks again all.
Parent - - By jwright650 (*****) Date 03-13-2019 18:36
Regarding: Increasing the voltage for cover passes.

This may be true for 3/8" coupons, but for 1" thickness, the plate has plenty of heat in it. By the time you cap it off you don't want  or need the extra heat to flatten the cap passes, especially for a 2G coupon.
Parent - - By Lawrence (*****) Date 03-13-2019 23:35
:::::Pulling hair out!

Heat...  

more heat...

less heat.....  

turn up the heat a little....

Voltage has so little to do with “Heat” that it is almost negligible!

Zip...  Zero.... Nada !!!!

Voltage (electrical pressure)  controls the arc length... nothing more.

Wire Feed Speed and Electrode Extension control amperage (Electrical volume)

Amperage = Current = Volume = Energy = Heat!

Amperage is all the water in the river. {WFS}

Voltage is putting all that water through a fire hose {Arc Length}

How’s that for turnin up the heat?
Parent - By dalevel47 Date 03-14-2019 11:03
Thanks for sharing.
Parent - - By jwright650 (*****) Date 03-14-2019 11:17
Lawrence,
Regardless of how your speak about it(or pull your hair), turning down the voltage (keeping the ESO and the WFS the same) on the cover pass makes the filler material stay in place instead of falling out(FCAW and GMAW) because at some point you cannot travel across the coupon quick enough without turning the voltage down a little....or you can take a trip to the water fountain and wait for it to cool off on it's own. I've capped a bunch of 1" plates off in my few trips around the sun of pulling the trigger. I realize the shape of the arc (length and cone shape) gets longer with more voltage, shorter with less voltage but when you turn up the voltage you can add a lot more filler(WFS)...why?...because it "melts", turn down the voltage and you cannot add WFS because it just will "not melt" the filler at that rate, unless you count the fireworks display and huge spatter as the unmelted wire is now plowing into the puddle instead of being melted into the puddle....sure sounds like we are adding heat.
Parent - By Lawrence (*****) Date 03-14-2019 16:14
I'm just having some fun John...  (I guess sort of at your expense,,, I apologize)

The moral of the story for GMAW is that when we say "heat" it means nothing unless we say more eh?

I really like your response because it demands another aspect of the process is considered !   Excellent !

So if we have undercut (too much heat) might have something to do with voltage (even though the current *energy* remains constant)

If we have a lack of fusion, (not enough heat) no matter what Johnny does with the voltage knob, it probably isn't going to help.

We must say more...

"That cap has undercut... Looks too hot.. Turn it down a volt"    Now you have communicated !

"That root looks too cold on the macro... Lets increase the WFS 50 IPM to get more amperage"...  Now we have communicated !

Fun with welding words...   Important words that mean things.
Parent - - By SeeJeepGo (*) Date 03-14-2019 15:06
"Gotta turn up the heat a little"

You're cold? OK ill go adjust the thermostat a few degrees.
NO? that's not what you meant?
OK show me the 'HEAT' control knob on the welder?
That one? NOPE that's voltage!
:grin:
Parent - - By Newt18 (*) Date 03-14-2019 22:09
Hi SeeJeepGo. C8 shielding gas runs a little smoother. Fun to experiment.
            Did you end up with two root passes or a single? Single pass roots, key is seeing keyhole at both bevels at the weld toes.
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Parent - By Newt18 (*) Date 03-14-2019 22:30 Edited 03-15-2019 14:18
Hi All. I apologize posting pics and running off. Lawrence, excellent info on voltage and amperage. SeeJeep, too funny and so true! I may use that!!

         The first 3 pics are a exercise using .045 ER70S-6, C10 gas, Miller 452 power source. I may have a welder in training run some short  pad welds with both parameters to distinguish arc differences and how it relates to weld profile, and later fusion, penetration.

         Last 3 pics. Super fun welding!  A consumables verification test. Looooooonnngg story short, feds wanted it done.
                  20 some stringer beads,  metal core .045 E80Ni1, C10 gas, 390wfs, 25.5 volts. Everything passed. I have the side bends somewhere here and will try to post pics of those.
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