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Is a 320 amp welder required to weld schedule 40 8" carbon steel pipe?
Reply:no no no
Reply:Probably not. Your question is a bit vague. More info would help get you a better answer.Wall thickness is about 5/16" for 8" sch 40 from the table I checked. We have students weld 3/8"  plate up at about 125-140 amps using 1/8" rods. Bigger rods would need more amps, but I doubt you'd need 300 amps other than possibly to have a high duty cycle..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Originally Posted by 123weldno no no
Reply:you need at least 500.
Reply:Originally Posted by TimmyTIGyou need at least 500.
Reply:This is all the info I received from the lead project manager. 8" schedule 40 carbon steel pipe has a wall thickness of 32/1000 of an inch.According to AWS, 1 amp of current is required for each 1/1000 of pipe wall thickness.The plan is to do the root weld with 6010 or 6011 1/8" rod. 7018 1/8" and 3/32" rod for the filler and cover pass. (this is what our welder requested for rod to use)They also stated that E7018 low hydrogen electrodes must be maintained at a temperature exceeding 200F degrees as they are used.
Reply:The machine we have is a Miller Bobcat 225 and the machine they think we should have is the Miller Big Blue 350 pipe pro.
Reply:Information like that is only accurate to a certain extend, 7018 1/8 you won't be running much higher than 130 amps.
Reply:Originally Posted by iongarInformation like that is only accurate to a certain extend, 7018 1/8 you won't be running much higher than 130 amps.
Reply:BTW, I was just messing with you with the 500 comment. If they want to buy you a bigger machine, well, why not?
Reply:Originally Posted by tinner50This is all the info I received from the lead project manager. 8" schedule 40 carbon steel pipe has a wall thickness of 32/1000 of an inch.According to AWS, 1 amp of current is required for each 1/1000 of pipe wall thickness.The plan is to do the root weld with 6010 or 6011 1/8" rod. 7018 1/8" and 3/32" rod for the filler and cover pass. (this is what our welder requested for rod to use)They also stated that E7018 low hydrogen electrodes must be maintained at a temperature exceeding 200F degrees as they are used.
Reply:Originally Posted by tinner50Is a 320 amp welder required to weld schedule 40 8" carbon steel pipe?
Reply:Originally Posted by rafergusonThe guys just want the latest and greatest welder, just like we would all like a Corvette.   ;-)
Reply:Originally Posted by tinner50The machine we have is a Miller Bobcat 225 and the machine they think we should have is the Miller Big Blue 350 pipe pro.
Reply:Inadvertent postOOPS!Brain [email protected] the confusion.Last edited by geezerbill; 01-20-2015 at 11:13 AM.Hobart Beta-Mig 2511972 Miller AEAD-200LEMiller 250 TwinNorthern Ind. Hybrid 200Longevity Stick 140Longevity Migweld 200SThermal Arc Pak 3XR
Reply:Originally Posted by tinner50This is all the info I received from the lead project manager. 8" schedule 40 carbon steel pipe has a wall thickness of 32/1000 of an inch.According to AWS, 1 amp of current is required for each 1/1000 of pipe wall thickness.The plan is to do the root weld with 6010 or 6011 1/8" rod. 7018 1/8" and 3/32" rod for the filler and cover pass. (this is what our welder requested for rod to use)They also stated that E7018 low hydrogen electrodes must be maintained at a temperature exceeding 200F degrees as they are used.
Reply:Originally Posted by MinnesotaDaveWhy?  Did they make one with an on-board welder now?
Reply:Originally Posted by BistineauIt's going to be an option package on the 2015 models, driven from a PTO in the transmission. With the V-8 power plant turning it, it is supposed to put out like 650-700 amps @ 100% duty cycle. It will only be available on the 4WD versions, so it will be great for the pipeline welders.
Reply:Originally Posted by MinnesotaDaveWell, just as long as there are enough cup holders....
Reply:Originally Posted by MinnesotaDaveWell, just as long as there are enough cup holders....
Reply:Typing error. I meant 320/1000
Reply:Out of curiousity, what is this welded pipe system going to be used for?
Reply:Chilled water lines for air conditioning in a 10 story building consisting of 62 condo units on Grand Cayman Island
Reply:Your BC should do just fine for that project. Have you thought about upgrading it to the 2250 version like I suggested above? It is a cheap and easy modification to do.Where would I find documentation showing the proper procedure for welding this pipe? So I can prove that we don't have to buy the new machine.
Reply:Depending on the contents of the pipe, and pressure. I'd be concerned with weldor skill, then welder. Pipeline weldors use 200 amp welders in some cases. I don't know of any using a Bobcat for pipeline work. A small percent use Trailblazer type machines.An optimist is usually wrong, and when the unexpected happens is unprepared. A pessimist is usually right, when wrong, is delighted, and well prepared.
Reply:Originally Posted by tinner50Where would I find documentation showing the proper procedure for welding this pipe? So I can prove that we don't have to buy the new machine.
Reply:Originally Posted by tinner50Where would I find documentation showing the proper procedure for welding this pipe? So I can prove that we don't have to buy the new machine.
Reply:Originally Posted by tinner50Where would I find documentation showing the proper procedure for welding this pipe? So I can prove that we don't have to buy the new machine.
Reply:Been here for years. This is the type of work we do best. The owner is willing to spend the $17,000.00 on the new machine. I just resent some book smart person that has never got his hands dirty in his life telling me I need more machine than I actually need to do the job I know we can do with the equipment we have.
Reply:Tinner,You can pay for a copy of a pre-qualified welding procedure for SMAW on pipe from the AWS.  Here's an example from a third party( NOT and endorsement of their products, I just pulled this link from a quick search for "pre-qualified pipe welding procedures)http://www.wpsamerica.com/SMAW-Partial-AWS%20D1.1.pdfHere's another link to a union training manual, local 597 out of Chicago, Il:http://www.pftf597.org/assets/1/7/We...ion_Manual.pdfPage 15 of the manual instructs the reader to weld E7018 electrodes using 115-165 amps for fill passes on pipe.(I'd say 110-125 amps but that's me and my welding machine)Here's one of the foundation references for pipe welding procedureshttp://www.amazon.com/Pipe-Welding-P.../dp/0831131411Here's the link to the AWS pre-qualified procedure for welding carbon steel pipe, 1/8" through 3/4" thick, with E6010 and E7018 electrodes.  It's not cheap, but it lists all the essentials for making a successful pipe weld, including amperage ranges.http://pubs.aws.org/p/76/b21-1-20119...lded-conditionThe info is out there but you'll have to dig or pay for it.Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:Originally Posted by tinner50Been here for years. This is the type of work we do best. The owner is willing to spend the $17,000.00 on the new machine. I just resent some book smart person that has never got his hands dirty in his life telling me I need more machine than I actually need to do the job I know we can do with the equipment we have.
Reply:Originally Posted by A_DAB_will_doTinner,You can pay for a copy of a pre-qualified welding procedure for SMAW on pipe from the AWS.  Here's an example from a third party( NOT and endorsement of their products, I just pulled this link from a quick search for "pre-qualified pipe welding procedures)http://www.wpsamerica.com/SMAW-Partial-AWS%20D1.1.pdfHere's another link to a union training manual, local 597 out of Chicago, Il:http://www.pftf597.org/assets/1/7/We...ion_Manual.pdfPage 15 of the manual instructs the reader to weld E7018 electrodes using 115-165 amps for fill passes on pipe.(I'd say 110-125 amps but that's me and my welding machine)Here's one of the foundation references for pipe welding procedureshttp://www.amazon.com/Pipe-Welding-P.../dp/0831131411Here's the link to the AWS pre-qualified procedure for welding carbon steel pipe, 1/8" through 3/4" thick, with E6010 and E7018 electrodes.  It's not cheap, but it lists all the essentials for making a successful pipe weld, including amperage ranges.http://pubs.aws.org/p/76/b21-1-20119...lded-conditionThe info is out there but you'll have to dig or pay for it.
Reply:Maybe their concern is that a smaller machine will encounter down time, if pressed hard.The machine you have, while it is capable of the required amperage at 100% duty cycle, may not satisfy their requirements due to the nature of the machine.They may feel the 700cc twin may be working too hard, screaming along at 3600 RPM all day, day in and day out.I am not sure if the individual who set the restriction is The GC, or the Engineering firm, but if they have the final say, I am really not sure I would purchase this machine for one job.Now, if having a machine that fulfills their requirements, means you will be getting a lot of their work, and your machine isn't going to be sitting around idle the majority of the time, I'd consider buying.If it is a one-time gig, or sporadic work, I think I'd rent a machine that they approve.Now, if the owner of your company insists on buying the Big 40, tell him it is a wise choice because the 225 is a piece of crap, and tell him I offered to buy it for scrap, I can send you my address, if he goes for itHobart Beta-Mig 2511972 Miller AEAD-200LEMiller 250 TwinNorthern Ind. Hybrid 200Longevity Stick 140Longevity Migweld 200SThermal Arc Pak 3XR
Reply:The donkey in me can't pass it up... Every welder better have a welder on board. It's the WELDOR that may be optional Last edited by mmitchell; 01-23-2015 at 11:09 PM.Reason: Couldn't see the color script
Reply:If this pipe has to be welded to code, the person doing the welding needs to be properly qualified. What's really suspect is that someone qualified to do this type of welding to code/x-ray would know that the Bobcat, although not the preferred machine, is more than capable of doing the job. Kind of scary actually. You wouldn't get away with something like that here.
Reply:New member  from ireland
Reply:If I was welding that joint in the field with an engine drive.  I'd put that root in about 130 if it was beveled to a knife edge. Fill passes would be about 200ish.  Cap would be about 180 amps.  Walking the cup the whole way out. I would use a #8 cup 17 series torch and about 30 on the argon.
Reply:Anyone working on a pipe line at the moment?
Reply:Originally Posted by tinner50This is all the info I received from the lead project manager. 8" schedule 40 carbon steel pipe has a wall thickness of 32/1000 of an inch.According to AWS, 1 amp of current is required for each 1/1000 of pipe wall thickness.The plan is to do the root weld with 6010 or 6011 1/8" rod. 7018 1/8" and 3/32" rod for the filler and cover pass. (this is what our welder requested for rod to use)They also stated that E7018 low hydrogen electrodes must be maintained at a temperature exceeding 200F degrees as they are used.
Reply:8" sch. 40 is 320/1000. Nobody is going to weld at 320 amps with 1/8" electrode.  Might AWS be referring to single pass welds of the sort you might see on manufactured oil tanks. A sch 40 8" pipe is going to get at least three passes to weld, is likely to be done with 1/8" electrode of two different varieties. With variations in technique, running continuously, you do overhead, vertical up, maybe down and flat. I've never seen a Bobcat weld look as nice without stopping to reset the dials. FieldRes or Tozzi do it with antique 200 amp Lincolns seamlessly without adjusting anything. Is a Bobcat capable of this? I don't know.An optimist is usually wrong, and when the unexpected happens is unprepared. A pessimist is usually right, when wrong, is delighted, and well prepared.
Reply:Excellent point, willie b.Probably the most salient so far.The old Lincoln 200's have been used on pipe all day long for how long now, about a million years?They have no more output, and no more duty cycle than the Bobcat (theoretically), but if they were equivalent machines, you would see the Bobcats on pipelines.A Bobcat is not an SA200.So the issue becomes: Can the machine do the job dependably, with little fiddling or running back and forth to the machine, and little down time, dependably and consistently?I'm not saying it can't be done.As a matter of fact, If I had the chance, and it involved welding out flanges on the 8" pipe, or weldnecks, or 90's, and I could roll them out, and the machine was nearby, I think I could use my AEAD200, the sort of predecessor to the Bobcat.If I were several stories up, doing position welds, and my machine were on the ground, I'd rather have a real pipe machine.Hobart Beta-Mig 2511972 Miller AEAD-200LEMiller 250 TwinNorthern Ind. Hybrid 200Longevity Stick 140Longevity Migweld 200SThermal Arc Pak 3XR
Reply:Actually, we know that a million years places it before Adam & Eve. I know beyond the shadow of a doubt that Adam's wish to buy an expensive welder would have been discouraged by Eve. She wanted new drapes for the dining room.An optimist is usually wrong, and when the unexpected happens is unprepared. A pessimist is usually right, when wrong, is delighted, and well prepared.
Reply:Originally Posted by tinner50This is all the info I received from the lead project manager. 8" schedule 40 carbon steel pipe has a wall thickness of 32/1000 of an inch.According to AWS, 1 amp of current is required for each 1/1000 of pipe wall thickness.The plan is to do the root weld with 6010 or 6011 1/8" rod. 7018 1/8" and 3/32" rod for the filler and cover pass. (this is what our welder requested for rod to use)They also stated that E7018 low hydrogen electrodes must be maintained at a temperature exceeding 200F degrees as they are used.
Reply:Originally Posted by tinner50The machine we have is a Miller Bobcat 225 and the machine they think we should have is the Miller Big Blue 350 pipe pro.
Reply:If it is a new building plug in a inverter or hard hat motor generator . Pipe is welded withLincoln 5 P plus 1/8 & 5/32. 200 amps is all you need. Air cooled gas drives are not used in the pipe field even though they work.No fitter or pipeliner would think of it.