Fluxcore welding - downhill pipe

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After much discussion in other threads, I thought I'd start a thread that discusses fluxcore welding.  The focus is on self-shielded fluxcore(ss-fcaw) and downhill welding techniques.That said, if folks have pictures and questions about gas shielded fluxcore and uphill or non-pipewelding applications.  Feel free to speak up.I'll be posting some photos of some practice welds I've been making as a part of learning to weld with a new(to me) E71T-8 welding wire.The first photo is just a view of the shop and some of the typical pipe I'm working on.  36" diameter, with XX10 root pass and ss-fcaw hot pass, fill, and cap.  We also do some short circuit MIG root pass, using metal-core wire on a Miller pipepro, and their RMD process.Second photo is of the cap on a weld on that same pipe.  Taken at about 3 o'clock.  The cap in this case is a split stringer bead welded downhill with ss-fcaw.Next post will be photos of the same wire and process on 6" schedule 80... Attached ImagesBenson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:So here are some photos of some fair to decent downhill welds on 6" sch 80 pipe.  Welds were made in the 5G position.  The root pass was made with RMD and metal-core wire.  Hot pass, 2 fills and cap were E71T-8 ss-fcaw wire.1st photo is the root RMD pass.  2nd photo is the inside of the root pass.  3rd phot is the 3 o'clock position on the pipe.  4th photo is the bottom of the pipe.Next series I'll try some split cap stringers and get some photos of the fill passes. Attached ImagesBenson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:Nice stuff, thank you.  David Real world weldin.  When I grow up I want to be a tig weldor.
Reply:You're welcome.  I'm hoping to spark some more discussion, and clear up some mis-conceptions I think are floating around out there.Will see if I can come up with some variations on this theme; different wire brands, different equipment combinations.  Will also get some more time welding on large diameter pipe this week.Stay tuned... Originally Posted by David RNice stuff, thank you.  David
Reply:Nice pics but IMO, you are taking too big of steps with you vert up weave leaving yourself open for possible non-fusion areas and slag inclusions.
Reply:Did I miss something?  I thought this was vertical "down" that was being demonstrated.Esab Migmaster 250Lincoln SA 200Lincoln Ranger 8Smith Oxy Fuel setupEverlast PowerPlasma 80Everlast Power iMIG 160Everlast Power iMIG 205 Everlast Power iMIG 140EEverlast PowerARC 300Everlast PowerARC 140STEverlast PowerTIG 255EXT
Reply:Those last two pics aren't vert down.
Reply:Not sure, but I think object has been flipped over for better picture taking.He says vert down.Esab Migmaster 250Lincoln SA 200Lincoln Ranger 8Smith Oxy Fuel setupEverlast PowerPlasma 80Everlast Power iMIG 160Everlast Power iMIG 205 Everlast Power iMIG 140EEverlast PowerARC 300Everlast PowerARC 140STEverlast PowerTIG 255EXT
Reply:I'll swear on anything you like that those welds are vertical down.  I rolled the pipe on the stand to get a better shot of the bottom half.Regardless, I'll agree that smaller steps are better.  I'm working on dialing in the wire feed speed for what works best for me. Until I figure that out, I'm making sure I stay at the leading edge of the puddle. Originally Posted by weldrwomnThose last two pics aren't vert down.
Reply:The way the weld  "lays in" gives it away for me.  It just has that easy, fast look to it.Esab Migmaster 250Lincoln SA 200Lincoln Ranger 8Smith Oxy Fuel setupEverlast PowerPlasma 80Everlast Power iMIG 160Everlast Power iMIG 205 Everlast Power iMIG 140EEverlast PowerARC 300Everlast PowerARC 140STEverlast PowerTIG 255EXT
Reply:I'll give you fast lugweld.  Easy is debateable.  It's easier with leathers and ear plugs to keep the sparks from burning out my ear drums.  But it's not as easy as short circuit MIG or pulsed spray MIG.  7018 uphill is easier for me now, although I'm starting to think that this fluxcore might be easier in the longrun, if only because the gun stays about the same distance from the work.   Originally Posted by lugweldThe way the weld  "lays in" gives it away for me.  It just has that easy, fast look to it.
Reply:I'm sorry I didn't mean easy as in effortless.  I meant easy in the sense there is no complicated weave or pausing or puddling.  It is straight down the center of the weldment.Esab Migmaster 250Lincoln SA 200Lincoln Ranger 8Smith Oxy Fuel setupEverlast PowerPlasma 80Everlast Power iMIG 160Everlast Power iMIG 205 Everlast Power iMIG 140EEverlast PowerARC 300Everlast PowerARC 140STEverlast PowerTIG 255EXT
Reply:Originally Posted by A_DAB_will_doThe root pass was made with RMD and metal-core wire.
Reply:Craig,- Solid Mig wire is what it sounds like, solid wire.  It starts out as large diameter solid green rod and is drawn down to its final diameter.  -Metal cored wire starts out as metal strip and is rolled into a semi circle. From there, ground up metal powder is poured into the middle and the strip is rolled over to complete the circle and it is drawn down to its final diameter.  Metal cored wires provide high deposition rates and are great for poor fit-ups becuase they have a very fluid puddle.Hope this helps.Welding is my hobby, I just happen to get paid for it!
Reply:Carolina Welder:Welding is my hobby, I just happen to get paid for it! Congratulations: find something you love doing and make money doin' it. Thanks for the explanation. Which brings up the next question. It seems that the solid wire would have more mass / density, leaving a heavier deposit, than a recompressed powder.  Is the metal-core available in a larger diameter for some reason? Or because of its microscopic porosity (better atomization; my visualization), can you run it at higher wire speeds to get more metal down?I'm guessing it's a xx2x something, flat, maybe horizontal.Thanks againExplain has an i; explanation only has one i. Weird.  oops, driftingLast edited by Craig in Denver; 01-26-2009 at 09:56 PM.Reason: , wrong . right9-11-2001......We Will Never ForgetRetired desk jockey. Hobby weldor with a little training. Craftsman O/A---Flat, Vert, Ovhd, Horz. Miller Syncrowave 250
Reply:Hey CraigI know that 7014 is a high deposition rod with an iron powder coating.I'm going out on a limb, because i'm not sure, but I think it has to do with the difference between a spray transfer, and a globular transfer.  Maybe I'm way the hell off the mark, and it would be good if someone clarified it.Then there's the faster meltoff rate between DCEN and DCEP with some rods.I think it all has to do with what's goin' on in the plasma within the arc"Any day above ground is a good day"http://www.farmersamm.com/
Reply:And as far as vert. down welding with a wire machine.....  You can still have a decent weld if you stay ahead of the puddle, and run stringers.  It's done a lot."Any day above ground is a good day"http://www.farmersamm.com/
Reply:Downhill is NOT reccommended with wire feed.The American Welding Society came out with a 10 year report of many cases of cracked welds as the wire feed travel speed was too high and resulted in cracking on boat hulls.It is preferred to make the weld going uphill ensuring penetration and some preheating in the weld grove.Last edited by Donald Branscom; 01-27-2009 at 12:52 AM.AWS certified welding inspectorAWS certified welder
Reply:Originally Posted by farmersammHey CraigI know that 7014 is a high deposition rod with an iron powder coating.I'm going out on a limb, because i'm not sure, but I think it has to do with the difference between a spray transfer, and a globular transfer.  Maybe I'm way the hell off the mark, and it would be good if someone clarified it.Then there's the faster meltoff rate between DCEN and DCEP with some rods.I think it all has to do with what's goin' on in the plasma within the arc
Reply:holy lack of fusion bat man the pics of the stringers in the bevel have bust written all over them. what is the advantage of running a cored wire downhill?
Reply:I know it's not reccomended, but it is done.I think the problem comes when you try to build the deposit, rather than letting the deposit follow the gun.  It takes the heat out of the leading edge of the puddle."Any day above ground is a good day"http://www.farmersamm.com/
Reply:Originally Posted by Donald BranscomThe 7024 is called the iron powder rod. It has a lot of deposit and is good for flat welds or fillets. It has a dark brown coating.Often called a drag rod.
Reply:BULLSH!T!!!!Y'all got me thinkin' I'm losin' my mind.  Rooted around in the closet to come up with the damn rods.  I ain't got alzheimers yet Attached Images"Any day above ground is a good day"http://www.farmersamm.com/
Reply:Solid wire is denser, but deposition rates for metal core wire are higher.  It has to do with the heat generated by the electric current running through the thin-walled sheath, versus having the entire cross-section of the solid wire as a path for conducting electricity.Metal core is larger in diameter to accomodate the powder squeezed inside the metal sheath.  It's difficult to draw any kind of flux or metal core wire down to smaller diameters without splitting the sheath open or breaking the wire.  I think, but I'm not certain, that it's also harder to maintain a consistent fill inside the sheath as you go to smaller and smaller diameters. Originally Posted by Craig in DenverCarolina Welder:Welding is my hobby, I just happen to get paid for it! Congratulations: find something you love doing and make money doin' it. Thanks for the explanation. Which brings up the next question. It seems that the solid wire would have more mass / density, leaving a heavier deposit, than a recompressed powder.  Is the metal-core available in a larger diameter for some reason? Or because of its microscopic porosity (better atomization; my visualization), can you run it at higher wire speeds to get more metal down?I'm guessing it's a xx2x something, flat, maybe horizontal.Thanks againExplain has an i; explanation only has one i. Weird.  oops, drifting
Reply:I would agree with your statement if you limited it to short circuit MIG.  You can get good penetration downhill, while weaving, with with pulse-spray, fcaw, and metal-core because the heat is a lot higher than short-circuit MIG. Originally Posted by farmersammAnd as far as vert. down welding with a wire machine.....  You can still have a decent weld if you stay ahead of the puddle, and run stringers.  It's done a lot.If this were stick welding, I'd tend to agree with what you said quasi.  The root pass does not have the same appearance with RMD(regulated metal deposition), but the penetration is good.  If you want more info on RMD, check herehttp://www.millerwelds.com/swf/flv/f...=335&h=230&v=8LIncoln has a similar process they abbreviate STT.  Not sure what that acronym stands for.Even so, the followup passes with metal-core or fcaw are hot enough to burn in and make for a strong weld.  I'm much more concerned with trapped slag in the ss-fcaw than any issues with the root pass.FCAW downhill is fast and hot.  It's much faster than uphill welding.  There are fewer restarts than with stick welding, which ultimately leads to fewer defects.  In the world of high strength pipeline welding, the lower overall heat input/build up in the base metal makes for a smaller heat affected zone.  This is better for the steel's mechanical properties.  This isn't real common in North America, but overseas and in offshore welding it's becoming very common.SS-FCAW is ideal for outdoor welding because there are no shielding gas concerns.  It's downside is that applications in thin wall pipe are limited right now because it tends to burn through the root.  The thinner the pipe, the greater the likelihood of this problem occurring. Originally Posted by quasiholy lack of fusion bat man the pics of the stringers in the bevel have bust written all over them. what is the advantage of running a cored wire downhill?
Reply:Donald,Alot has changed in 10 years and downhill welding with FCAW is common everywhere outside of North America on pipeline construction and offshore rig construction.  Pulsed spray MIG for mechanized downhill welding is common in automated equipment for pipeline welding.  FCAW is commonly used in Europe, Russia, China, and the Middle east.  Stick welding is still used as well in these places, but FCAW has a definite niche as well.These industries are generally not governed by AWS standards; API is much more applicable.  There are also a host of international standards and certification bodies; ABS, DNV, Lloyds, and others I can't remember off the top of my head.   Originally Posted by Donald BranscomDownhill is NOT reccommended with wire feed.The American Welding Society came out with a 10 year report of many cases of cracked welds as the wire feed travel speed was too high and resulted in cracking on boat hulls.It is preferred to make the weld going uphill ensuring penetration and some preheating in the weld grove.
Reply:Samm,You are right.  7014 is an iron powder rod.  So is the less prevalent 7024 and even more scarce 6027 and maybe a few more.  But I think the 7014 is more widely used as it may be used on something less than flat.Esab Migmaster 250Lincoln SA 200Lincoln Ranger 8Smith Oxy Fuel setupEverlast PowerPlasma 80Everlast Power iMIG 160Everlast Power iMIG 205 Everlast Power iMIG 140EEverlast PowerARC 300Everlast PowerARC 140STEverlast PowerTIG 255EXT
Reply:Kinder/Morgan has a pipe job in Ohio going now.6010 root down hill9018 hot pass up hillFluxcore fill & cap down hill
Reply:I'm guessing you're referring to the REX pipeline project.  I'm aware of that, but it's one of just a handful of fluxcore welded pipelines here in North America.  There's not much else that's done with fluxcore.  There's one short stretch of pipeline out west, and maybe some stuff that was built by TransCanada.There are some major pipelines; 52" diameter and 1000's of KM long being built between Russia and China. Originally Posted by FinneyKinder/Morgan has a pipe job in Ohio going now.6010 root down hill9018 hot pass up hillFluxcore fill & cap down hill
Reply:Originally Posted by lugweldSamm,You are right.  7014 is an iron powder rod.  So is the less prevalent 7024 and even more scarce 6027 and maybe a few more.  But I think the 7014 is more widely used as it may be used on something less than flat.
Reply:STT is Lincoln's "Surface Tension Transfer".  It's a waveform (aka pulse) type of welding that is neither CV nor CC.  The claim is that it is a low-heat no spatter good fusion process especially suited for sheetmetal and root pass open root pipe joints.  It's not 'plain' short-circuit transfer, and it's not spray transfer, but the description looks like it's a complex mostly short-circuit pulse with some voltage sensing and spikes and dips in the current to make the puddle and transfer a molten droplet from the wire as it touches the puddle.  The best laid schemes ... Gang oft agley ...
Reply:Before I get out of hereI wonder if downhill welds are more feasable with FCAW than SMAW.The filler that I'm familiar with(forget the stuff, but it's in my damn machine) seems to have a very fast freeze, and the puddle doesn't want to pass you by going downhill.  It is still a faster travel to keep ahead of the puddle, but nowhere near as fast as trying it with a rod."Any day above ground is a good day"http://www.farmersamm.com/
Reply:Originally Posted by MoonRiseSTT is Lincoln's "Surface Tension Transfer".  It's a waveform (aka pulse) type of welding that is neither CV nor CC.  The claim is that it is a low-heat no spatter good fusion process especially suited for sheetmetal and root pass open root pipe joints.  It's not 'plain' short-circuit transfer, and it's not spray transfer, but the description looks like it's a complex mostly short-circuit pulse with some voltage sensing and spikes and dips in the current to make the puddle and transfer a molten droplet from the wire as it touches the puddle.
Reply:Don't know if STT is in the 'Bible' or not, but it's mentioned in the general product catalog and in the GMAW Guide c4200, pages 6, 10, and 18-21.  The best laid schemes ... Gang oft agley ...
Reply:Originally Posted by MoonRiseSTT is Lincoln's "Surface Tension Transfer".  It's a waveform (aka pulse) type of welding that is neither CV nor CC.  The claim is that it is a low-heat no spatter good fusion process especially suited for sheetmetal and root pass open root pipe joints.  It's not 'plain' short-circuit transfer, and it's not spray transfer, but the description looks like it's a complex mostly short-circuit pulse with some voltage sensing and spikes and dips in the current to make the puddle and transfer a molten droplet from the wire as it touches the puddle.
Reply:I don't know what exactly STT is, but would like to find out.  It seems to be like pulsed spray, but uses Co2 for the gas instead of Argon/Co2 blends.  Got me curious.  All the STT machines from Lincoln are 3 phase which I do not have in my shop .......Yet   .7024 is an awesome rod, works best on AC and can be faster than MIG and works in the higher amp ranges than short circuit.  Leaves a beautiful bead FAST.  Slag falls off.  I have used it on a few jobs.  It makes quick work out of long fillets or grooves only in the flat position.What this has to do with downhill pipe?  Nuttin, sorry....David Real world weldin.  When I grow up I want to be a tig weldor.
Reply:[QUOTE=Carolina Welder;246540]Craig,- Solid Mig wire is what it sounds like, solid wire.  It starts out as large diameter solid green rod and is drawn down to its final diameter.  -Metal cored wire starts out as metal strip and is rolled into a semi circle. From there, ground up metal powder is poured into the middle and the strip is rolled over to complete the circle and it is drawn down to its final diameter.  Metal cored wires provide high deposition rates and are great for poor fit-ups becuase they have a very fluid puddle.I'm lost!Do you use gas with metal core or is there flux in it also?A butterfly without wings, is just an ugly bug
Reply:David.I put a rotary phase converter in my shop. a 20hp one cost @ 2k. You might get by with a smaller one for one welder. mine draws of a 125A single phase 220v breaker.it was more like 40K to get it hard wired from the grid and i could see the transformer from my door.The wiring wasn't that hard. i did it myself....some big wires though.G
Reply:hijack over...sorry
Reply:[quote=Magnetic Mechanic;246892] Originally Posted by Carolina WelderCraig,- Solid Mig wire is what it sounds like, solid wire.  It starts out as large diameter solid green rod and is drawn down to its final diameter.  -Metal cored wire starts out as metal strip and is rolled into a semi circle. From there, ground up metal powder is poured into the middle and the strip is rolled over to complete the circle and it is drawn down to its final diameter.  Metal cored wires provide high deposition rates and are great for poor fit-ups becuase they have a very fluid puddle.I'm lost!Do you use gas with metal core or is there flux in it also?
Reply:Originally Posted by Magnetic MechanicI'm lost!Do you use gas with metal core or is there flux in it also?
Reply:Quote by A_DAB_will_doI'm guessing you're referring to the REX pipeline project. I'm aware of that, but it's one of just a handful of fluxcore welded pipelines here in North America. There's not much else that's done with fluxcore. There's one short stretch of pipeline out west, and maybe some stuff that was built by TransCanada.There are some major pipelines; 52" diameter and 1000's of KM long being built between Russia and China.From what I understand they are having a lot of problems & repairs.
Reply:I have a few to add but having a hard time posting them.Last edited by Sparky#1; 01-28-2009 at 08:31 AM.
Reply:Actually it's relevant David.  STT or RMD are both intended to improve root pass quality and reduce the amount of skill necessary to put in a good root pass on pipe.  I can't speak about STT because I haven't had a chance to weld with it.  But RMD is a kind of short circuit MIG welding.  Computers in the weldor monitor the arc parameters constantly, and make small adjustments to produce a very smooth puddle.  This low turbulence puddle ensures good fusion to the sidewalls, and reduces spatter.  The power supply is a CV/CC machine, but whether on not the process is one or the other I can't say.Miller claims that RMD roots can forgo hotpass beads in many instances because they're thicker than a typical xx10 root pass.  They also claim that when welding stainless steel pipe, sometimes you can forego using a back purge.  The puddle is so stable that the shielding gas from the gun is able to sufficiently protect both sides of the root pass.  There's video for all of this on Miller's website.The RMD process is supposedly easier because there's little or no gun manipulation required.  With the right joint geometry, all the welder has to do is strike an arc and move smoothly down the joint.  Generally speaking I agree with this.Insofar as shield gas is concerned.  The RMD process needs at least an 80/20 Ar/CO2 mix.  The exact type of shield gas is dependent on the filler metal being used. Originally Posted by David RI don't know what exactly STT is, but would like to find out.  It seems to be like pulsed spray, but uses Co2 for the gas instead of Argon/Co2 blends.  Got me curious.  All the STT machines from Lincoln are 3 phase which I do not have in my shop .......Yet   .7024 is an awesome rod, works best on AC and can be faster than MIG and works in the higher amp ranges than short circuit.  Leaves a beautiful bead FAST.  Slag falls off.  I have used it on a few jobs.  It makes quick work out of long fillets or grooves only in the flat position.What this has to do with downhill pipe?  Nuttin, sorry....David
Reply:I don't know one way or the other about that. Originally Posted by FinneyFrom what I understand they are having a lot of problems & repairs.
Reply:Looking forward to seeing your pictures.  I'll try and take some more today, once I shovel a path through the snow to the shop.   Originally Posted by Sparky#1I have a few to add but having a hard time posting them.
Reply:OK, Here's the next installment of pictures.  These are welds on 36" diameter pipe.  The wall thickness is 12mm, or about 1/2", I think.1 - overview of weld2 - Downhill root pass with RMD3 - Inside root pass with RMD4 - Defect in root pass; insufficient feathering of tack/restart; coupled with incorrect gun manipulation(too steep travel angle)5 - First fill pass from 12oclock to 3oclock with ss-fcaw downhill Attached ImagesBenson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:Continuing:6 - 2nd fill pass at ~3oclock on pipe7 - 2nd fill pass, area with excessive fill; too high wirespeed, I think8 - 2nd fill pas with toe lines lightly ground out, easier to lay in cover pass with clear edge to follow9 - 1st pass of a 2 bead cap.  Heat input lower due to higher travel speed.  Flatter profile and better control of bead width10 - 2nd pass still has slag coating.  This wire is almost self peeling.  It's cleans off with a scrape of a chipping hammer and a quick pass wiht a wire wheel.  If it doesn't clean up this easy, something is wrong.  (pipe too cold, incorrect WFS and/or voltage)One more post... Attached ImagesBenson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:Last set for today:11 - Here's a shot of the completed weld from 12 to 3oclock.   Ordinarily, I'd finish each pass before moving on to the next.  Welding by myself I'd alternate quarters on the pipe as well12 - Another shot of the cap where I stopped welding.  I try to stagger the restarts so they don't stack up.13 - An example of a serious problem from a different pipeweld.  Get too far outside the voltage window, or neglect to clean slag deposits from the toe lines of a preceeding weld pass, and you get what you see here.  Ugly porosity.  The only fix I know of is to grind or gouge all this porous material away and re-weld.   Don't ever weld overtop this, because the porosity will not disappear.  It will propagate to the surface and make the problem worse. Attached ImagesBenson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector