Question about volts vs. wire speed

admin

Got a question that I'm sure most of you already know. To my understanding, wire speed is essentially amps. Most migs have a voltage setting, but are classed in amps. How do you figure amps with a volt reading and wire speed. For example, I used to mig weld for a company that made pre-fab buildings. We ran 30volts and 400 ipm on wire speed with .045 wire(if that even matters). What amperage were we welding at?
Reply:Hello wstmrlnd89639, all 3 of those items factor into the answer to your question. I was just recently at a Miller training session and that subject was discussed. Now I am having a hard time finding the graphs that the Miller tech referred to in his discussion, they are located on Miller's website and I'll try hard to find them for you and post a link.      Think about the 3 items that you mentioned: voltage - wirespeed - wire diameter. If you have 30 volts/400ipm. wirespeed/.023 wire diameter, you'll likely have quite a different scenario(a really bad one) than if everything is the same except for possibly using .045 dia. wire with the other settings being the same. Shielding gases can even have an effect on the outcome of machine settings, considering that higher argon content shielding gases can promote better "across the arc" energy in some cases. I will be interested to see what others have for input on your topic, meanwhile I'll continue to look for the information that I mentioned at the beginning of this post. Best regards, Allanaevald
Reply:Originally Posted by Wstmrlnd89639To my understanding, wire speed is essentially amps.
Reply:Ok, I understand that wire speed is not acually amperage. I know that it is in conjuntion with voltage. So your telling me that there isn't some kind of formula to determine amperage based on the voltage and the amount of wire being consumed? That doesn't make sense to me. How in the heck is amperage figured then? Changing gears, if the size of the consumable changes the amperage, then why is a stick welder listed in amps when the electrode is unknown? I'm having a problem understanding the relationship between voltage, amperage, and the electrode. Why does a stick welder have adjustable ampereage, but a mig welder has adjustable voltage? one has amps as the unknown, and one has volts as the unknown. There has to be a mathmatical relationship between volts, amps, and apparently the size of the electrode or wire. Anyone?
Reply:Originally Posted by Wstmrlnd89639Ok, I understand that wire speed is not acually amperage. I know that it is in conjuntion with voltage. So your telling me that there isn't some kind of formula to determine amperage based on the voltage and the amount of wire being consumed? That doesn't make sense to me. How in the heck is amperage figured then? Changing gears, if the size of the consumable changes the amperage, then why is a stick welder listed in amps when the electrode is unknown? I'm having a problem understanding the relationship between voltage, amperage, and the electrode. Why does a stick welder have adjustable ampereage, but a mig welder has adjustable voltage? one has amps as the unknown, and one has volts as the unknown. There has to be a mathmatical relationship between volts, amps, and apparently the size of the electrode or wire. Anyone?
Reply:Thanks Ed. It does help my understanding some. It's just after reading probably 1000 posts on here John Doe says he welded x with y welder at z settings. The usual response is you need more amps. I'm just trying to get a baseline for the mystery "amps". One more question. My first post I said we welded at 30 volts and 400 ipm. That was my tweaked settings. Standard the machines were set up at 30 volts 380 ipm. When I first picked one up I was like "What the?". As far as i can tell they were set up to spray arc. I was so used to short circuit that I thought something was wrong. Assuming that it was spray arc, which I am under the impression is a hotter, slower, more penetrating weld, would it not be acually run at a lower amperage than short circuit with the same amount of voltage given the reduction in wire speed?
Reply:The manufacturers are bold enough to list some "rules of thumb" for inches per minute/per amp. All based on the assumption that the voltage range is set correctly (as per their recs) for the amperage required and you are using one of the common gas mixes recommended for that wire. These are for solid wires of course. The flux cores are more difficult to get a trend on and you must resort to researching each individual wire and compiling your own info. They (the manufacturers) realize that nothing is constant nor absolute but that some ruff numbers are necessary for one to be able to get in range by some other way than using those flakey door charts. Keep in mind the ipm per amp is not perfectly linear when represented on an graph. It tends to be a curve and their rule of thimb numbers are for that portion of the graph that is the flatter. Naturally there is always a point where there begins to be less and less amp advantage by cranking up the speed and more of just piling on the wire kicks in. Of course each manufacturers chart may vary from one to another, however they all appear to be reasonably close. Here is one example. General Wire Burn Off Rates: .023 -3.5" ipm = 1amp  .030 - 2" ipm = 1amp .035 - 1.6" ipm = 1amp .045 - 1"   ipm = 1ampGeneral Practical Amp Ranges:.023 = 30-90 amps.030 = 40-145 (190 max) amps.035 = 50-180 (280 max) amps.045 = 110-360 amps"The things that will destroy America are prosperity at any price, peace at any price, safety first instead of duty first, the love of soft living and the get rich quick theory of life." -Theodore Roosevelt
Reply:Is this the same OP who's looking for an engineer's help in sizing an I-beam for a 50'x50' structure?He may have "worked for a prefab erector" but he's in way over his head with the work he's bidding.This type post/poster scares the hell out of me.Syncro 250 DX Dynasty 200 DXMM 251 w/30A SG XMT 304 w/714 Feeder & Optima PulserHH187Dialarc 250 AC/DCHypertherm PM 1250Smith, Harris, Victor O/ASmith and Thermco Gas MixersAccess to a full fab shop with CNC Plasma, Water Jet, etc.
Reply:Way over my head? It was a question. I usually get my supplier to calculate beam requirements. I was just wanting a second opinion to check against their recommendations. And I know I must be a real dummy for asking the mathmatical correlation for volts, amps, and wire speed. And I was not an pre-fab erector, I was a fitter/welder for the structural steel. There is no reason to be scared sundown.
Reply:To OP:For the sake of this thread, amperage doesn't matter in wire welding. The important thing is results or penetration & puddle shape, bead size. So amp curiousity aside, that's why all the machines are set up to adjust volts & wire speed.If you are comparing stick (constant current) to Mig (constant voltage), that might be why you're interested in amps. With all other variables (voltage, wire stick-out, arc length, gun angle, wire dia.) constant, then wire speed will control amperage. But 200 ipm does not mean 200 amps.The Welding Handbook Vol. 2 8th Edition  (ISBN  0-87171-354-3) available from the AWS will give you all the theory on welding processes you could want.Weldtek
Reply:http://www.hobartwelders.com/weldtal...=joules&page=3EnjoyEd Conleyhttp://www.screamingbroccoli.com/MM252MM211 (Sold)Passport Plus & Spool gunLincoln SP135 Plus- (Gone to a good home)Klutch 120v Plasma cutterSO 2020 benderBeer in the fridge
Reply:Thanks guys. This was mostly for amusement. Just thougt there might be a formula or something. I was mostly interested in the theory. Thanks a lot.
Reply:Wstmrlnd89639 let's back up a minute. Originally Posted by Wstmrlnd89639. . . We ran 30volts and 400 ipm on wire speed with .045 wire(if that even matters). What amperage were we welding at?
Reply:This thread made me think of a question I had the other day.  My mig machine has a spec for XXXamps at YY% duty cycle.  It would be nice to know how many amps I'm pulling based on voltage and wire speed so I could get a feel on how long I can run the machine.  My machine doesn't have any amp gauge, nor do I feel like shelling out the cash for a meter capable of measuring in the 100+ range.  Sure I could make a shunt, but how do you calibrate it?So far the "run it 'til the safety pops" method hasn't resulted in any popping of the safety. Dynasty200DX w/coolmate1MM210MM VintageESAB miniarc161ltsLincoln AC225Victor O/A, Smith AW1ACutmaster 81IR 2475N7.5FPRage3Jancy USA1019" SBAEAD-200LE
Reply:Originally Posted by AndyAThis thread made me think of a question I had the other day.  My mig machine has a spec for XXXamps at YY% duty cycle.  It would be nice to know how many amps I'm pulling based on voltage and wire speed so I could get a feel on how long I can run the machine.  My machine doesn't have any amp gauge, nor do I feel like shelling out the cash for a meter capable of measuring in the 100+ range.  Sure I could make a shunt, but how do you calibrate it?So far the "run it 'til the safety pops" method hasn't resulted in any popping of the safety.
Reply:Sandy, thank you for catching on to my point. Ok, before they set every welder to the same voltage/ wirespeed, it was up to the welder to set up his/her own welder. About everybody was short circuit welding(Sizzling Bacon). We had a couple of welds fail UT and they mandated the welding parameters. When I say spray transfer, that was literally what we were doing. We were spraying the wire into the weld. It was slower, and very easy to undercut. I give it a bump on wire speed to combat the undercutting. Anyway, theoretically speaking, If a welder increases amps when wire speed is increased, wouldn't we have actually decreased amperage by reducing the wire speed to achieve spray transfer? Or am I missing something about spray transfer. More voltage and less wire speed= less amps? Going back to my question about stick vs. Mig, one being CC one being CV(which I understand) it was the theory I was after. Why one machine adjusts voltage and one adjusts amperage to achieve the same goal.
Reply:I'm far from the expert on this but I would suspect what would happen with spray if one just keeps cranking up the wire speed outside the manufacturers recs for that wire is that at some point you are going to reach then exceed the current saturation capabilites of that particular wire. Once that happens then you would enter a zone where you are starting to just push in and pile on the wire beyond the machines ability to keep it in the spray (fine droplet) mode with the existing voltage setting. In short you go beyond the flatter part of the feed speed/amp curve and start into the steeper part of the slope. In short the last 100 ipm doesn't generate as much of an amperage increase as the 1st 100 ipm but yet the volume of filler has increased on a one to one basis."The things that will destroy America are prosperity at any price, peace at any price, safety first instead of duty first, the love of soft living and the get rich quick theory of life." -Theodore Roosevelt
Reply:Pretty lousy pic but it's at the limits of my computor savy. I didn't crop it air anything, just left it like I snagged it. Just food for thought. Attached Images"The things that will destroy America are prosperity at any price, peace at any price, safety first instead of duty first, the love of soft living and the get rich quick theory of life." -Theodore Roosevelt
Reply:Originally Posted by Wstmrlnd89639 Why one machine adjusts voltage and one adjusts amperage to achieve the same goal.
Reply:I agree Sandy. From my (way over my head as Sundown says) experience, more wire speed at a given voltage just results in a cold, piled up piece of bird poo. Or at least thats where it ends up past the sweet spot. I havne't got a machine to start spraying by turning the wire speed up past short circuit mode. From my (wayyy over my head experience like I weld skyscrapers with a HF 60amp MIg) we turned the voltage up and wire speed down to spray. Maybe it wasn't "spray", but let me tell you, when the wire came out of the nozzle it turned in to liquid droplets and the arc pushed it into the weld with a hiss and no spatter,I don't know what else to call it.
Reply:THanks for your inout Broccoli. My mid thinks of electricity as water/ Psi= volts amps=volume so on and so forth. It works fine until you get into the complexities of it
Reply:Originally Posted by Wstmrlnd89639 . . .I haven't got a machine to start spraying by turning the wire speed up past short circuit mode. . .
Reply:The Power Law / Ohm's Law relation explains it. Learn that, and you'll have the answer to the mathematical reasons for why you are running the amperage that you are. The factors that determine the values that you must plug into the formulas involved in the power law are determined by your machine settings and imho, the arc length that you maintain, as the operator. I have yet to see wire speed in any Power Law / Ohm's Law relationship. But arc length plays a key role in this entire scenario. The arc gap has a direct impact on circuit resistance, because of the impedance in air.City of L.A. Structural; Manual & Semi-Automatic;"Surely there is a mine for silver, and a place where gold is refined. Iron is taken from the earth, and copper is smelted from ore."Job 28:1,2Lincoln, Miller, Victor & ISV BibleDanny
Reply:Got that, Tanglediver.But since gun position has very little impact -if any - on arc length, and none on feed rate, how can the solution be derived from Ohm's law? Or let's say that everything is exactly fixed and doesn't vary at all throughout the weld; even then how can Ohm's law be applied to answer the question of : "How do you figure amps with a volt reading and wire speed?" I agree there must be a formula, but what?Good Luck
Reply:Originally Posted by Wstmrlnd89639Got a question that I'm sure most of you already know. To my understanding, wire speed is essentially amps. Most migs have a voltage setting, but are classed in amps. How do you figure amps with a volt reading and wire speed. For example, I used to mig weld for a company that made pre-fab buildings. We ran 30volts and 400 ipm on wire speed with .045 wire(if that even matters). What amperage were we welding at?Originally Posted by tanglediver. . .I guess my point is that wire speed is not essential data. I would put my clamp meter on the work lead; done, but is that cheating? Have Alfred watch the meter while I run a bead...
Reply:I'm surprised nobody has quoted the miller MIG handbook yet, so I will... (page 8)I find the chart (the second one pictured) interesting - .045 wire is roughly 1ipm per amp. Obviously a rough guideline, but good for mental calcs in the field...Jason Attached ImagesXMT 350 MPA Dynasty 280DXSuitcase 8RC / OptimaSpoolmatic 30AThermco Ar / C02 mixerAssorted O/A gear
Reply:BCRD,The info -was- posted, back on Page1, by Sandy.    Post #7.  And note that those numbers apply in the short-circuit linear amps-vs-WFS relationship only (see also Sandy's  Post #18 with the image of the WFS-vs-amperage curves, which look just like they came out of the Lincoln GMAW guide document c4200).Denrep, I don't think Alfred will see 500 amps going through 0.045 solid steel wire.  Unless the current-vs-WFS curves are waaaay different than the ones I've seen so far, it looks like 0.045 solid steel wire will reach current saturation around 450 amps or so.  Close but less than 500 amps.  It will be interesting to see what amperage you get when you push that 0.045 wire at 700 ipm.  I think you'll definitely need a 500+ amp power source (and a honking big gun/torch as well as the wire feeder itself) in order to do the experiment though.  Thanks for 'taking one for the team' by doing the experiment.     Seriously.Lincoln shows 0.045 at 500 IPM and 30V with C10 at 340 amps in spray transfer.  I think you have to go to an 0.062 solid wire to go over 500 amps.  The best laid schemes ... Gang oft agley ...
Reply:Ahh, your right. My bad...Maybe I'll win next time...JasonXMT 350 MPA Dynasty 280DXSuitcase 8RC / OptimaSpoolmatic 30AThermco Ar / C02 mixerAssorted O/A gear
Reply:Hey BCRD, all in good fun.  Have a    The best laid schemes ... Gang oft agley ...
Reply:Ok. going with the ohm's law way of thinking, couldn't you produce the same amount of electrical energy by increasing the volts with the resulting decrease in amps? I don't know how watts would calculate into a welder, but 30 volts and 300 amps, and 25 volts and 360 amps are the same amount of wattage. I know that may not mean a hill of beans to a welding machine. I'm starting to wish I hadn't started wondering about the way a welding machine processes electricity and paid more attention when I took AC/DC theory.
Reply:Originally Posted by MoonRise. . . It will be interesting to see what amperage you get when you push that 0.045 wire at 700 ipm.  I think you'll definitely need a 500+ amp power source (and a honking big gun/torch as well as the wire feeder itself) in order to do the experiment though.  Thanks for 'taking one for the team' by doing the experiment. . . .
Reply:Originally Posted by Wstmrlnd89639Ok. going with the ohm's law way of thinking, couldn't you produce the same amount of electrical energy by increasing the volts with the resulting decrease in amps? I don't know how watts would calculate into a welder, but 30 volts and 300 amps, and 25 volts and 360 amps are the same amount of wattage. I know that may not mean a hill of beans to a welding machine. I'm starting to wish I hadn't started wondering about the way a welding machine processes electricity and paid more attention when I took AC/DC theory.
Reply:EEEYOwwww!At 42V/690IPM with C25 you made a pretty big smoke cloud there denrep. When you push wire too far in spray (what you call dig), heavy hard wire guys call it modified glob transfer. The arc cone narrows and penetration is deep. There is some of this done on heavy equipment but mostly where things that really don't mean anything are getting stuck together.The upside is speed and good surface appearance, the downside is poor side wall fusion and an elongated nipple shape at the root (you can do the same with sub-arc).For the OPs question on duty cycle, the chart also shows amperage input to the machine as well as output so clamping one of the input legs can serve the purpose. Somewhere I have the equation for calculating the duty cycle for any given NEMA II tagged machine at any given output (I wouldn’t bet on finding it fast though)…Matt
Reply:Thanks for all the input guys. Although I have more questions than answers. I just need to tell that little voice in my head to go away and do what is proven and what works and quit worring about why it is what it is. I kind of feel sorry for my math teacher now. I'm the one that wants to why I am doing something rather than just doing it because its the right way.(and for those wondering I am not high school, Just trying to finish college a few years late). Anyway, I do understand that a welding machine has more brains than I do when calculating electrical properties. Welder=win Me=Fail. Thanks again for the input.
Reply:Most of the older wire feeds used to always have volt and amp guages,in fact when i went to welding school the procedure books we used told the recomended amps and volts, not wire speed. I also wonder sometimes how many amps i am actually running because of the fact that i was taught that way.
Reply:that interesting Nodak.Most machines Ive used only listed volts, but I guess that makes sense now sense it is a constant and amperage is a variable.
Reply:Originally Posted by Wstmrlnd89639Thanks for all the input guys. Although I have more questions than answers. I just need to tell that little voice in my head to go away and do what is proven and what works and quit worring about why it is what it is. I kind of feel sorry for my math teacher now. I'm the one that wants to why I am doing something rather than just doing it because its the right way.(and for those wondering I am not high school, Just trying to finish college a few years late). Anyway, I do understand that a welding machine has more brains than I do when calculating electrical properties. Welder=win Me=Fail. Thanks again for the input.
Reply:Thanks BRCD. I have a better understanding of what I was after, but there are so many variables. I mean each machine is different and the characteristics of different brands of wire are different. The main thing is (Sundown this is aimed at you) I know from experience what is accceptable and what is not. My feable brain will continue to ponder all these electrical properites, but my consience will be sound asleep.
Reply:feeble I mean. See how feeble my brain is?
Reply:Denrep, thanks for the great demo! I think you may have stumbled on a new cutting process, GMAC/G.  Originally Posted by denrepBut since gun position has very little impact -if any - on arc length,
Reply:Originally Posted by denrepOkay, I stayed after school and gave it a stab, literally, using  .045 ER70S6 and Argon CO2 mix, probably 75-25.And I say  "a stab" because that's what happened, at about 400 amps the wire stabbed right through 3/8 and would simply cut a slot. I flashed one tip almost immediately and I didn't run very long out of respect for the 200 amp gun. There was nothing resembling a usable controllable deposit until things were dialed back close to recommended range.I don't see where straight CO2 would make much difference.Good Luck
Reply:Originally Posted by MoonRiseUmmm, yeah.  400 amps will go through a little piece of 3/8 inch thick plate in an instant.. . .vaporized the 'little' 3/8 plate before any fill from the wire could happen.I would have suggested to run 400 amps in 'spray' on at least some 1/2 inch plate or better some full inch thick stuff.And at 42 volts, you are waaaaay past the 'recommended' settings for that wire.  I think at 42 volts and 400 amps on some 3/8 plate you were more just cutting the plate and not welding it.  As you found out.   . . .
Reply:Originally Posted by denrepI didn't have a nearby heavier plate that I was willing to waste but I'm sure that it would simply dig a trench. And of course the object was to see if the wire would run way beyond recommended parameters; which it wouldn't. Hey! This may be workable for "desperate man" gouging.Anyway, good question Wstmrlnd89639 and  good job BCRD on producing the math formula; we knew there had to be a way.Good Luck
Reply:Originally Posted by Broccoli1isn't that Formula for determining Wire Speed?EFS- Electrode Feed Speed
Reply:This is from the Thread I linked to earlier on the Hobart site"The issue of what voltage is / does when GMAW welding can be complicated. All the answers brought up already are correct to some degreeVOLTAGE - voltage changes mainly arc length. You typically set the voltage to yeild the arc characteristic you desire for a give WFSVoltage as Heat InputAs already noted voltage affects your heat input so it is correct to state voltage is heat and therefore more voltage can yield higher penetration ( not always true though ! )BUT.... It is incorrect to assume that voltage is the governing variable that affect heat inputHEAT INPUT - heat input into a weld is very simply calculated as current X voltage X 60 / linear travel speed ( units in kJ/inch ) All heat input calculations in welding are done using this formulaIt is not important to undertand the formula but rather the general idea on how V and amps vary the end resultFor example, a typical GMAW procedure guidline for short circuit w/ 100%CO2 on mild steel has the voltage ranging from approximately 17volts to 22 volts . These recommened produres cover material thickness from 24Ga to 1/4 "Again it is not important to undertand the numbers but rather to cover the voltage range for short circuting up to 1/4 you only vary the voltage about 5 volts . If you plug a 5 volt variation into the heat input formula the heat input goes up, but it only goes up about 30%However, if you look a the same procedure charts, from 24ga to 1/4 you can see the current range from approximately 40 to 200 amps . Plugging this variation into the heat input calculation yields a 400% increase in heat input CONCLUSION FOR HEAT INPUTFrom the exercise above, you can see that although voltage does increase heat, the governing variable that varies heat input ( therefore penetration ) is a amps ( which is dicatated mainly by Wire Feed Speed )Still not convinced , set up some 18 gauge material to a nice short circuit transfer . If you crank up voltage, your arc length gets long and the end of the electrode starts trying to blob off. The puddle will wet out but most likely will not burn throughTurn voltage back down and now peg the WFS . Assuming you have a decent size machine, it is easy to burn a hold right through the plateTo increase your penetration ( heavier material for example ) it is generally best to increase WFS to increase the current and tweak the voltage to yield the desired arcIf someone can let me know how to post into a reply a clip from a adobe file I can put up some cross sections of welds showing the effect of variablesWhat Else Does Voltage Do Once voltage is set to yield a desired arc characteristic ( short arc , spray etc ) you can tweak the voltage to flatten the bead profile. In general, more voltage yields a flatter beadAlthough many people assume it flattens due to arc force etc, it is WAAAAY more simple than thatA good analogy is spray painting. If you move the spray can closer the line gets narrower. If you move it away, it gets wider. It is geometry of a triangle. As the electrode gets further away ( higher voltage / longer arc length ) , the "cone or tent" it forms gets wider. It as simple as thatBecause the rate of wire feed is constant, if wire gets "spread out " more on the plate the bead gets wider and less high . This is why on a fillet weld excessive voltage will cause undercut. There is not enough material to be spread around to fill what the arc is digging out. Turning down the voltage reduces how much the material is getting spreadHope this clarifies some of this"Link againhttp://www.hobartwelders.com/weldtal...=joules&page=2Ed Conleyhttp://www.screamingbroccoli.com/MM252MM211 (Sold)Passport Plus & Spool gunLincoln SP135 Plus- (Gone to a good home)Klutch 120v Plasma cutterSO 2020 benderBeer in the fridge
Reply:Originally Posted by Broccoli1isn't that Formula for determining Wire Speed?EFS- Electrode Feed Speed
Reply:Originally Posted by BCRDYes it is, but it shows the relationship between EFS and current (I). It'll take a little algebra to solve for I, and that is the only equation I have found yet.Jason
Reply:Originally Posted by Broccoli1This is from the Thread I linked to earlier on the Hobart site"The issue of what voltage is / does when GMAW welding can be complicated. All the answers brought up already are correct to some degreeVOLTAGE - voltage changes mainly arc length. You typically set the voltage to yeild the arc characteristic you desire for a give WFSVoltage as Heat InputAs already noted voltage affects your heat input so it is correct to state voltage is heat and therefore more voltage can yield higher penetration ( not always true though ! )BUT.... It is incorrect to assume that voltage is the governing variable that affect heat inputHEAT INPUT - heat input into a weld is very simply calculated as current X voltage X 60 / linear travel speed ( units in kJ/inch ) All heat input calculations in welding are done using this formulaIt is not important to undertand the formula but rather the general idea on how V and amps vary the end resultFor example, a typical GMAW procedure guidline for short circuit w/ 100%CO2 on mild steel has the voltage ranging from approximately 17volts to 22 volts . These recommened produres cover material thickness from 24Ga to 1/4 "Again it is not important to undertand the numbers but rather to cover the voltage range for short circuting up to 1/4 you only vary the voltage about 5 volts . If you plug a 5 volt variation into the heat input formula the heat input goes up, but it only goes up about 30%However, if you look a the same procedure charts, from 24ga to 1/4 you can see the current range from approximately 40 to 200 amps . Plugging this variation into the heat input calculation yields a 400% increase in heat input CONCLUSION FOR HEAT INPUTFrom the exercise above, you can see that although voltage does increase heat, the governing variable that varies heat input ( therefore penetration ) is a amps ( which is dicatated mainly by Wire Feed Speed )Still not convinced , set up some 18 gauge material to a nice short circuit transfer . If you crank up voltage, your arc length gets long and the end of the electrode starts trying to blob off. The puddle will wet out but most likely will not burn throughTurn voltage back down and now peg the WFS . Assuming you have a decent size machine, it is easy to burn a hold right through the plateTo increase your penetration ( heavier material for example ) it is generally best to increase WFS to increase the current and tweak the voltage to yield the desired arcIf someone can let me know how to post into a reply a clip from a adobe file I can put up some cross sections of welds showing the effect of variablesWhat Else Does Voltage Do Once voltage is set to yield a desired arc characteristic ( short arc , spray etc ) you can tweak the voltage to flatten the bead profile. In general, more voltage yields a flatter beadAlthough many people assume it flattens due to arc force etc, it is WAAAAY more simple than thatA good analogy is spray painting. If you move the spray can closer the line gets narrower. If you move it away, it gets wider. It is geometry of a triangle. As the electrode gets further away ( higher voltage / longer arc length ) , the "cone or tent" it forms gets wider. It as simple as thatBecause the rate of wire feed is constant, if wire gets "spread out " more on the plate the bead gets wider and less high . This is why on a fillet weld excessive voltage will cause undercut. There is not enough material to be spread around to fill what the arc is digging out. Turning down the voltage reduces how much the material is getting spreadHope this clarifies some of this"Link againhttp://www.hobartwelders.com/weldtal...=joules&page=2
Reply:Originally Posted by Go1lumYour formula of heat input gives Joules/In not kJ/In. In order to get kJ/in you need to add in another conversion factor by dividing everything by a 1000