vertical down 7018
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  1. #1

    vertical down 7018

    I have a weld test at a big company tomorrow and I need help.

    The test is on plate with 1/8th land and gap in vertical. The root must be 1/8th 7018 downhill. This goes against everything I've ever been tought in school. But it will be backgouged after completion of the first side so I guess it's alright.

    If any of you guys or girls have tips for me, I could sure use it. During practice the slag would get in front of the puddle and I can't get any fusion. It's got to be thick enough to get a hot pass in there without blowing through the root. Only the root is downhill.

  2. #2
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    May 2006
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    Re: vertical down 7018

    Perhaps that is the first part of the test - you telling them that it should be done Vertical UP. What company and what do they do? If it's structural, you better say vert. up....or instant failure.
    John
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  3. #3

    Re: vertical down 7018

    Structural. This is the engineered welding procedure.

    1st pass: 1/8th 7018 downhill
    2nd pass: 1/8th 7018 uphill
    3rd pass: 5/32 7018 uphill
    4th 5th and 6th pass: downhill wash passes with 1/8th 7018

    Backgouge

    1/8th 7018 uphill
    then,
    downhill wash pass with 1/8th 7018

  4. #4
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    Re: vertical down 7018

    Quote Originally Posted by barnacle8 View Post
    I have a weld test at a big company tomorrow and I need help.

    The test is on plate with 1/8th land and gap in vertical. The root must be 1/8th 7018 downhill. This goes against everything I've ever been tought in school. But it will be backgouged after completion of the first side so I guess it's alright.

    If any of you guys or girls have tips for me, I could sure use it. During practice the slag would get in front of the puddle and I can't get any fusion. It's got to be thick enough to get a hot pass in there without blowing through the root. Only the root is downhill.
    7018 is not reccommended for vertical downhill past 10º.
    Maybe they mean the welding coupon is vertical down, but you would weld vertical up.
    Maybe they want you to question the instructions?
    They may not know themselves so look it up in a book and tell them.
    The HOBART pocket guide says only 10º downhill with 7018.

  5. #5
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    Re: vertical down 7018

    I agree with the others, I could never find a good enough reason to weld 7018 down.

  6. #6
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    Re: vertical down 7018

    Never heard of it on a test. That's a trick some of us oilfield welders use when building things out of magnitized pipe but there is never a test involved. I've seen some things I have built like that bent up like a pretzel but none of the welds failed so it does work. I have never built anything this way that could get someone hurt. I know what the books say too.

    Perhaps the engineer that wrote the procedure isn't up to snuff on welding procedure. I would question them on it. Please post your results with the test.

  7. #7
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    Re: vertical down 7018

    Lincoln does have a 7018, listed for 3G downhill ....

  8. #8
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    Re: vertical down 7018

    And if the weld proceedure/test calls for it, that's what you do.

  9. #9
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    Re: vertical down 7018

    I would question it for sure just to be safe, but if it is truly a downhill root with 7018. All I can say is run hot and fast. Stay ahead of the slag as you go down and don't weave. I agree. I've never heard of that before either.
    I'm a Lover, Fighter, Wild horse Rider, and a pretty good welding man......

  10. #10
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    Re: vertical down 7018

    Quote Originally Posted by Hammack_Welding View Post
    I would question it for sure just to be safe, but if it is truly a downhill root with 7018. All I can say is run hot and fast. Stay ahead of the slag as you go down and don't weave.
    Turn it up to 130 amps, again, hot and fast. Stay ahead of the slag. It can be used to repair undercut, but that is all I've heard of...or done for testing!
    City of L.A. Structural; Manual & Semi-Automatic;
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  11. #11
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    Re: vertical down 7018

    Quote Originally Posted by mark8310 View Post
    Lincoln does have a 7018, listed for 3G downhill ....
    Make sure you do not get "downhill" mixed up with "downhand".

  12. #12

    Re: vertical down 7018

    Well I past the test today. 100% X-Ray. Just backgouged all the stuff that was downhill welded and welded up.

  13. #13
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    Re: vertical down 7018

    Quote Originally Posted by mark8310 View Post
    And if the weld proceedure/test calls for it, that's what you do.
    I believe this is the kind of comments that started a huge dispute on another thread. Not trying to start anymore disputes, just a simple observation

    Lincoln does make a rod for vertical down, heres the link...

    http://www.mylincolnelectric.com/Cat...t.aspx?p=12740

    personally, i havent run 7018 downhill, or anything else for that matter. It seems a little odd to have a root go in downhill because there is good chance of slag inclusions and not getting proper penetration. I guess its a good thing they call for a back gouge on the WPS. If its allowed, i would run a big carbon and air arc the entire root out since you say you run the first pass on the backgouge vertical up.

    Im no engineer, im just a welder. I would be leary of any procedure that called for vertical down for a root pass in structural welding. Dont be scared to challenge an engineer, they arent perfect, and they dont know everything. I have been on tons of jobs that i have caught things that seemed out of place, brought it to the attention of a foreman, and the next day had different weld procedures.

  14. #14
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    Re: vertical down 7018

    Congrads on passing your test!!!!...I have never heard of a downhill 7018...I've down hilled 6010 before!!..I don't like that eather but I have seen it done with pipeliners and they swear by it...I can root it ok...but my fill passes scare me since I have a hard time staying ahead of my slag...I would like to see the procedure on that test if possible...What are you welding? You said structural I know...what are you building?
    Jonesy

  15. #15

    Re: vertical down 7018

    It sounds like I'm working on those huge bulk storage tanks you see in refinery's. I'll be burning a LOT of rod! Also had a 2G test.

  16. #16
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    Re: vertical down 7018

    nice job passing the test

  17. #17
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    Re: vertical down 7018

    That is definitely a new one on me with the 7018 downhill but I am supposing it has something to do with the back gouging. Lincoln does have a low hydrogen electrode specifically for downhill on pipe though I don't think they call it 7018. I just saw it a while back and thought hmmm, wonder how well it works, but since I don't use it that's about all I can say on it. I used to work in a shop where our test was Code 9 G6 on 6 inch with 6010 downhill root and hotpass and completed uphill with 7018, but when we worked on heavy stuff that was backgouged they didn't care how we put the first pass in. Congrats on passing as that is definitely not a common procedure.

    Jonesy - the trick on the downhill hotpass with 6010/6011 is crank it up and use arc force to keep the flux behind the puddle. It requires much less grinding on the hotpass to get rid of the wagon tracks. In the oilfield we usually only run 6010 up on the root if it's a tight fit up, and everything else we do downhill. In construction it was always uphill on the root and hotpass (threw me for a loop as I had never heard of such a thing). The rod itself was actually designed for downhill pipe welding, but it is good for many many things they never thought about, lol.
    The difference between art and craft is the quality of the workmanship. I am an artist.

  18. #18
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    Re: vertical down 7018

    Barnacle8,

    I just spent a month working on building a refinery storage tank. I hope you enjoy it more than I did. (Sorry, no pics...against refinery policy)

    For the rest of the crowd...7018 downhill (regular old 7018, nothing special) is a legit method for this type of construction. See below for why...

    The tank I worked on was built using 3/4" thick plate for the first ring or level. Each plate was 10' tall and 32' long, curved in a slight arc. The joints were single bevel, 1/8" root opening, and about a 70° included angle.

    Each plate was welded to its neighbor using 7018 downhill for the root pass. The horizontal girth welds that join one ring to the next were done with a specialized subarc rig. Didn't get to see or do any of that. Here's what I learned about the vertical welds used to assemble each ring of the tank wall:

    • Don't expect full penetration, just tie the two plates together. I found that about a 30-40° drag travel angle was best. What you want is enough arc force pushing back uphill to keep the puddle well established.
    • Strike the arc, and wait for the puddle to bridge the joint before you start moving down the root. You won't be able to see anything with all the slag and crap until you start to move. You'll figure out what a good start looks like after you screw up the first couple.
    • A slight side-to-side wiggle will help; it keeps the puddle centered in the root opening, and allows the slag to slip past the puddle on either side. This keeps your view of the puddle unobstructed. If you move too fast the puddle will break and you'll end up piling metal only on one side of the joint.
    • When(not if) you hit a big slag deposit further down the joint, pause and long arc over the slag, then back quickly up to where you left off with the sound weldment. This will burn out the slag and clear the way ahead(for a while). Yes, this may leave some porosity, but for this method you're going to back gouge the joint so it doesn't matter.
    • Run the rod hotter than you would for an uphill weave. This will help keep the slag from extinguishing the arc as is drips down off the puddle.


    The fill and cap on this technique are standard 7018 uphill. The foreman showed me how to fill the joint in 1 pass using a 20-30° push travel angle. This went against all my prior teaching, but seems to work. It does produce X-ray quality welds. It works much better because one pass is fewer opportunities to trap slag in the weld toelines. Again, you may run hotter than you're accustomed to in welding with multiple passes. This keeps the puddle large, and burns out the slag from the joint. Be ruthless with the grinder if you think you've got slag trapped in the toelines of the fill pass. Pause as long as you can on the toelines of the fill pass to ensure you burn all the slag out, tie completely into the base metal, and leave no crevice to trap slag in.

    For all you skeptics out there, there are legitimate reasons for running the joints on the storage tank in this fashion. Here's what I inferred about the process and why they use 7018 downhill. The 10' long vertical welds distort the plates and ruin the smooth arc on the side of the tank. The crew I worked with called this peaking; could be in or out depending on how the plates were fitted up. A little 'peaked-in' after the weld is run is better. Back gouging the weld and rewelding the root side of the joint will effectively negate the distortion from the face weld, and restore the joint back to the proper curvature. (if all goes perfectly...if not there's always sledgehammers and a system of dogs and what the tankers called 'bull-pins' to fix the joint.)

    Incidentally, unless the foreman says otherwise, run each pass completely from top to bottom before starting the next pass. I was welding up on a scaffold at one point, and thought it would be easier and faster to fill and cap as I went up the joint. This creates uneven distortion and makes it very difficult to get the distortion out of the plate evenly from top to bottom. Uneven distortion makes the foreman cranky.

    Incidentally, you can use 6010 downhill for the root on this as well. But the foreman I worked with advised against it. The 6010 root is thin, and tends to crack. This crack has to be gouged out, and is tough to see. If you miss, and don't get it all, the weld will fail X-ray inspection. This also makes the foreman cranky. The 7018 doesn't crack(usually). It's stronger weld metal, and leaves a thicker deposit.

    So, I hope all this helps you on the job site. For the rest, I hope you see why they use this technique in building at least some oil storage tanks. For my part, I hated running 7018 downhill. It's a royal PITA, but it does work. I don't like welding while hanging from a ladder on the side of teh tank. You'll almost certainly have to do this. I also don't like welding while someone else is using a sledgehammer on the tank wall 10' away. The noise is very distracting, and the wall of the tank ripples in and out 1/4" with each hammer stroke. Good vertical stickwelds are tough enough without trying to maintain arc length while working on a moving target.

    This type of heavy structural welding is different from welding pipe. To Dave R, and others, I understand why you guys run 7018 so much hotter than I learned to when I was in school for pipewelding. I think large, heavy plate weldments will dissippate much, much more heat than a weldment on pipe of the same thickness. Consequently, the structural plate welding can be run much hotter and you can pile up a lot more metal in the joint without burning through the root. Since the joint is purely vertical, you can stack a lot more metal without the puddle collapsing and running out of the joint, than you can on the same size weldment on pipe.

    Sorry for the dissertation...But I learned a lot even though I didn't like the job. I figured Barnacle8 might benefit from what I found out...
    Quote Originally Posted by barnacle8 View Post
    It sounds like I'm working on those huge bulk storage tanks you see in refinery's. I'll be burning a LOT of rod! Also had a 2G test.
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  19. #19
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    Re: vertical down 7018

    can someone help me to learn how to down vertical t joints. can you give me an opinion how to do it. i am currently a student and having problems with vertical down and up. can someone help me tell me the best smaw book i can purchase or videos i can watch

  20. #20
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    Re: vertical down 7018

    I am in the middle of a job right now that specifies 8018 electrode. I ordered some and when it showed up it was something I had never used before so I googled it and come to find out, it is ESAB but the description is what shocked me, it says it is specifically designed for downhill welding, learn something new every day.

    FILARC 27P
    SMAW

    This low hydrogen electrode is specially designed for downhill welding circumferential joints in pipes. The low hydrogen weld metal provides high notch toughness and excellent ductility to reduce the risk of cracking. The electrode is used particularly for pipelines, compressor stations, hot tapping and associated work using pipe steels in API 5LX52 to X70 grades in the oil and gas distribution industries, also process piping etc. Productivity is overall 25-30% faster than cellulosic electrodes and 40-50% faster than conventional low hydrogen electrodes for welding vertically up. Welding advice: Keep short arc using beaded or weaved runs. 2.5 mm size can also be welded uphill for increased heat input. DC- is preferred.
    Welding current
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  21. #21
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    Re: vertical down 7018

    All good stuff, old thread but good. I was brought up Never weld down hill. My welding instructor in college told me "Down hill weld is a wash"

    Then I started hanging around here. I guess its ok in some instances.

    Exhaust on a car I run from top center to bottom with my SP 100. Mig and Tig do not have slag to trap, so fast and hot makes for a thin bead but it will make a seal.

    If I did any down hill on a cell tower, I would be thrown off the job.

    Pipe welders do it all the time. I don't weld pipe. I have not burned 100 lbs of 6010 in my life.

    One time I had some prototype heat exchangers to weld and I did the base horizontal, then the four short sides down hill with pulsed spray. They ALL leaked. Next time it was turn them or weld up. 1/8 outside corners do not like to be welded uphill with pulsed spray, so It was turn them. If I had to to them again, I would tig them up.

    David
    Real world weldin.

    When I grow up I want to be a tig weldor.

  22. #22
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    Re: vertical down 7018

    Very good disertation A-DAB. I have seen shell plate fitted by boilermakers in school but never seen in real life. You filled in the gaps.

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