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Just read a reply from HAWK that stated 6010 1/8 inch rod for first pass, then followed with 7018 1/8 inch rod for filler and cover pass, is the acceptable way to do a pipe weld cert. test. To my understanding, (in the field, natural gas pipe) you are to use 6010 rod, all the way out to the cap weld, using 100% downhand (downhill) welding. 7018 rod would need to be done vertical (uphill). Any feed-back from you experienced pipe welders?
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1/16-7018 follow-up
Dseman& HAWK,
Thanks to both of you for your rapid responses.We will follow up on your good suggestion of asking the retailer for larger quantities.In your research did you ever come up with the true manf. name?
In answer to Hawk's question,I am a welder in a coal-fired power plant and we recently purchased Maxstar150stl for the convience of 110v and not having to lug a machine and leads up 6 or 7 floors. What we found(no fault of the machine)is that in the buildings away from the main plant there is a drop in amps.this does not let use 3/32 rod We thought 1/16 may help correct this problem.As far as the application it would be general repair but we do not generally use anything less than 7018.We do use some 5p but we were told by our supplier that there is not a good quality 1/16 5p on the market.
Again thanks to both of you! -
Re: 6010 and 7018 rod for pipe
At some point you will no longer be able to do downhill. Post this at Hobarts site and Mike Sherman or John McCracken will give you an answer.Originally posted by azgorilla
Just read a reply from HAWK that stated 6010 1/8 inch rod for first pass, then followed with 7018 1/8 inch rod for filler and cover pass, is the acceptable way to do a pipe weld cert. test. To my understanding, (in the field, natural gas pipe) you are to use 6010 rod, all the way out to the cap weld, using 100% downhand (downhill) welding. 7018 rod would need to be done vertical (uphill). Any feed-back from you experienced pipe welders?
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Re: 1/16-7018 follow-up
1206,Originally posted by 1206
Dseman& HAWK,
In your research did you ever come up with the true manf. name?
Somewhere in an email from Hobart I have the manufacturer's name, but I don't believe that it would be appropriate for me to indicate who that is. Besides, you wouldn't be able to buy from them directly anyways--that's not how they work.
-dsemanComment
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azgorilla,
My current pipe welding certification is for natural gas line. The process is 6010 uphill travel root, hot pass, and cap. This is the procedure specified by our local utility company. There are procedures for downhill 6010 root, fill, and cap. The down hill travel is more common than uphill. However, the direction of travel depends on several common variables: OD, Schedule, pressure, and the WE who wrote the procedure. Downhill travel is typically faster, but may require more passes and will not withstand the higher pressure tests that uphill travel can. Uphill travel is slower, requires fewer passes, and will withstand higher pressures.
Our utility board requires the following: 6 - G all position, vertical uphill travel, 6010 stick, Electrode Positive, from 3/32", 1/8", 5/32" depending on pipe OD and schedule. I found it best to take the test using 1" SCHD 40 pipe. This qualiifes for all schedules and OD's within the WPS limits range. The root must be open and equal to the rod diameter. The welding ID is ASME Sec IX for the current year. The base metal is pipe API 5L with the remaining designation determined by the project engineer.
Downhill travel is more prevalent in cross country pipelining. The uphill travel is a local procedure written in the 1950's and has never been revised.
Some newer procedures are 6010 and 7018 uphill travel.
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pipe welding
Thank you for the excellent reply! Totally blew me away with the in dept answer. Yes, I was thinking of the cross country mainliners on various types of gas pipe welding. You answered all questions. Again, thanks a lot.Comment
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pipe rod
Azgorilla where i weld 3/4 to 3 inch pipe is 6010 root 7010 hot pass filler and cap all passes downhand 4to 12 inch(all im qualified to)6010 root 8010 hot pass filler and cap all down hand.. tie ins could be spec'ed for filler and cap uphand 7018 or 8018 if your interested in natural gas pipe welding find someone in your area who can give you procedures for where you would want to test then ....practice...practice ....practice and talk to as many pipe weldors as posible find thier tricks try them and use what works for you....
thanks jimComment
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Scott, thanks for the input. I have welded for many years, including pipe. However, it has all been uphill, vertical welding. A while ago I was working with some gas guys on a cross country type maintenance job (repair work after an explosion that killed 3 by-standers). That was the first time I even entertained the idea of welding downhand. Thanks for the further info. and suggestions.Comment
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Azgorrila what caused the line break. guessing it was a fair sized line or high pressure or both
thanks jimComment
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The pipe line was a 16 inch dia. medium pressure gasoline/diesel line. They would run gas through it, put the (for lack of remembering what it is called) big black, solid 17 inch rubber ball into the pipe, (for separation of fluids) then chase it with diesel. Some smart construction worker decided they needed to dig with the backhoe on the site where the pipe was busied. Did not use locates, did not get permission, etc. Went ahead and dug, scraping the side of the pipe. Few months later, the pipe split in the middle of the backhoe bucket tooth scrape, releasing gasoline that ignited, killing three young people. Happened about 5 years ago....can not say where, because litigation proceedings are still going on.........Comment
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Re: 6010 and 7018 rod for pipe
5P+ (6010) is the most common rod used on beads (the root pass) but 7010 and 8010 are used on some pipe. Fill and cap are sometimes done with 6010 on lower grades of pipe but much more common is 70+ (8010) and sometimes 7010.Originally posted by azgorilla
Just read a reply from HAWK that stated 6010 1/8 inch rod for first pass, then followed with 7018 1/8 inch rod for filler and cover pass, is the acceptable way to do a pipe weld cert. test. To my understanding, (in the field, natural gas pipe) you are to use 6010 rod, all the way out to the cap weld, using 100% downhand (downhill) welding. 7018 rod would need to be done vertical (uphill). Any feed-back from you experienced pipe welders?
As for the size it depends on the pipe size, anything from 3/32" to 3/16" rod is used for beads, 5/32" is the most common on large line pipe, followed by a 5/32" or 3/16" hot pass, and 3/16" fill and cap. There is a downhill 7018 made for pipe, and it's used on some grades of pipe. All of this applies to downhill pipe welding.
JTMcC.Some days you eat the bear. And some days the bear eats you.Comment
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[QUOTE]Originally posted by HAWK
[B]azgorilla,
However, the direction of travel depends on several common variables: OD, Schedule, pressure, and the WE who wrote the procedure. Downhill travel is typically faster, but may require more passes and will not withstand the higher pressure tests that uphill travel can. Uphill travel is slower, requires fewer passes, and will withstand higher pressures.
I definitly have to disagree with this. Downhill is in common use on pipe over 1" in wall thickness, well over 2000 psi. Line pipe is the material of choice in pipeline construction, schedule pipe isn't. Speed, in my opinion, is roughly the same, and I have timed a lot of welds on a lot of different sizes of pipe, both uphill and down. Weld progression has nothing to do with the pressure that a piping system will contain, several other factors determine that.
regards,
JTMcC.Some days you eat the bear. And some days the bear eats you.Comment
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JTMcC,
Welcome to the forum.
Let me elaborate a little on my previous post from which you have posted as "quote". There are other factors that play a role in pipeline pressure ratings in addition to the weld travel position. However, I would rather make some generalized statements concerning the trade rather than delve head over heels into specifics: diameter, wall thickness, joint design, joint preparation, electrode type, electrode diameter, position of weld ( different than direction of travel), weld current changes during the process
Downhill vertical welds are very fast and very common on pipe of 1/2" wall thickness and less. It does require higher currents and faster travel speeds than uphill travel. Closed roots are common with this procedure.
Uphill travel is slower because the current is lower to avoid puddle roll out. This method of welding creates an extremely liquid puddle which is more apt to melt out gas holes. These welds are more common in heavier walled pipe. The slower travel creates a heavier more defined penetrating bead. Inherently these beads are more easily able to pass radiographic high pressure requirements.
Uphill travel is more common where high temperatures and pressures are found such as in power plant or petroleum refineries. Common sense will tell us heavier walled pipe will withstand higher pressures and temperatures than thinner walled pipe. Since uphill travel is the preferred method of welding these pipes many engineers spec the same process for smaller thinner diameter pipes used in high pressure applications.Comment
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Where I work we can't use 6010 for pipe. We have to use 7018 up hill root pass with a 1/8" gap. Then a 7018 cap up hill.. BobBob WrightComment
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As the owmner of a small pipe welding company for over 13 years, I have to disagree with just about every thing you say.Originally posted by HAWK
JTMcC,
Welcome to the forum.
Let me elaborate a little on my previous post from which you have posted as "quote". There are other factors that play a role in pipeline pressure ratings in addition to the weld travel position. However, I would rather make some generalized statements concerning the trade rather than delve head over heels into specifics: diameter, wall thickness, joint design, joint preparation, electrode type, electrode diameter, position of weld ( different than direction of travel), weld current changes during the process
Downhill vertical welds are very fast and very common on pipe of 1/2" wall thickness and less.
It does require higher currents and faster travel speeds than uphill travel. Closed roots are common with this procedure.
Uphill travel is slower because the current is lower to avoid puddle roll out. This method of welding creates an extremely liquid puddle which is more apt to melt out gas holes. These welds are more common in heavier walled pipe. The slower travel creates a heavier more defined penetrating bead. Inherently these beads are more easily able to pass radiographic high pressure requirements.
Uphill travel is more common where high temperatures and pressures are found such as in power plant or petroleum refineries. Common sense will tell us heavier walled pipe will withstand higher pressures and temperatures than thinner walled pipe. Since uphill travel is the preferred method of welding these pipes many engineers spec the same process for smaller thinner diameter pipes used in high pressure applications.
Where did you hear or read of the 1/2" or less? We regularly weld pipe over (sometimes WAY over 1/2") .620 wall, .820 wall, 1.000 wall and 1.125 wall pipe are commonly welded downhill.
Uphill and downhill, are in my experience very similar as far as speed goes. I base this on time and motion studies done personaly, to determine time spent per weld. We time just about everything we do, to make future bids easier. Downhill and uphill are equal in terms of speed of welds made.
Your comments on what engineers spec, doesn't jive with our real world experience. How much pipe do you do in a year? We do a lot, in many different enviroments, your comments just don't correlate with my experience.
Where in a powerhouse or refinery (and I have worked in quite a few of both) are pipe pressures higher than coming out of a natural gas compression station?
I only comment on work I am familiar with, and do regularly, and my remarks on down vs. up reflect that. I stand by them .
JTMcC.Some days you eat the bear. And some days the bear eats you.Comment
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