root 7018

[flange jockey]

i was curious as to how to please yer man thingy,so i tried a root with 7018 well they burned great.only kidding thingy.they say one picture is worth a thousand words, your still ahead and ive posted 20 pics018.JPG

[thingy]

Hey,flange man,,open root,7018,who ever figured that would work beats me,,vertical maybe,, ,,overhead and flat if I remember right[was only on one job that had that test,6g open root 7018,, didn't work very well,,rod ain't made to do that,,rod melts off inside coating,,6010 don't,,long arc is the thing cause you can't get it down in,,now as to that picture,,again pretty weld,,,how big is that pipe? thingy

[houlibar]

I've read you can root in with 7018 if you are really skilled. But dang, flange... do you have to make everything look as easy as falling out of your chair?

[jerryo]

I'm sure it gets done all the time, but most welding books will say that the 7018 rod should not be used for a root pass because of the possibility of trapping slag in the root. The 7018 produces a rather heavy amount of slag compared to some other rods, especially the 6010. On the other hand, Flange makes some absolutely beautiful root passes with his favorite rod, the 6013. I never thought of this rod as one to make root passes with either. Flange makes it look easy!

Flange, do you make your 6013 passes on pipe uphill or downhill? What amperage for a 1/8" rod? How much root gap?

[weldgault]

It is not recommended by anyone. Just don't do it. John

[Jonesy70]

I do alot of refinary work and Sunoco has band 6010 from the facility!!! we tig most roots but I have had to certify on a 7018 root for pipe and for all hot tapping!!! I don't like it...but I can do it!! My x rays seem to be passing!! Thats all that matters to me. 6010 is 60,000 tencile strenght...7018 is 70,000 tencile strenght...somewhere down the line a weld failed and someone tring to cover there A$$ made this claim and some engineer or inspector bought it and had a procedure change passed!! BUT...At Valero Refinary....they are welding process piping all the way out with 6010!! I passed my test there too..god it sucked...6010 requires so much more grinding to get it clean!! 7018 cleans up so much nicer!!

[thingy]

Well,you know they make 7010 and 8010,[think even 9010],so tensile ain't it,,7018 just ain't made for doing root passes,period,it don't work well,[or most of time not at all],,,but millions of miles of gas pipe is in the ground now that the root pass was made with 6010,[well,millions,maybe many thousands?],,,,it is made for running root pass,,,its just this downhill up hill thing,,,running up with 6010 root [pipefitters],they gap it wider,its generally thicker pipe,,you get more of a push through,,which restricks flow,etc,,downhill you gap it less,get less push through,,,,but tig root is without a doubt the best,,but its slower,,plus equipement,,gas,,shielding,etc,,,another thing,,7018,,lowhy,,,got to keep it low hy,[ovens,portable ovens,electric going off,people unplugging things,,etc],,if you take a 7018 out in the damp for 2-3 hours,it ain't low high anymores anyways,[porosity etc],,6010 its got mosture in the coating,,you put it in an oven,,coating will fall off,,,,asked an engineer one time[welding engineer] about this,,only thing he could come up with is hydrogen imbrittlement,,[which he is right,,in thicker stuff,or high carbon content steel,etc],,but on most mild steels,,7018 makes no sense at all,,,thingy

[enlpck]

It is not recommended by anyone. Just don't do it. John

It is REQUIRED in some circumstances. ABS and Lloyd's qualified procedures for hull plate are often 7018-1 root to cap.

The reason? 7018-1 makes the low temperature Charpy (kind of important in the north Atlantic) and the '10's don't as welded (the '10's are specd' at -20F, the '18-1 is at -50). I'v seen at least one job where '18 root was spec'd on refrigeration equipment, as well, due to the low temperature in service.

It's a wide, wide world out there. The shop I was in over the summer had more '18 root procedures than any other. The shop I spend most of my time in doesn't have any '18 root procedure, but everything is '18 or TIG cap. For pipeliners, '10 root to cap is quite common.

It is easier to trap slag using '18 for a root than '10, so it isn't something to do if not needed.

[weldgault]

I write procedures and companies go by them and ask no questions. I think sometimes procedures are written by people who don't know all the +'s and -'s of 10's and 18's. could write another book on the differences. John

[TRG-42]

Two reasons you don't see commonly E7018 for OPEN root welding ( not the same as a simple root pass )

Penetration - by definition of a E7018 the penetration is considered "medium" ( function of the fluxing / slagging system ) . Because of that if the joint ( land and gap ) are not pefect ....in the real world it NEVER is ...you won't have complete penetration ( more on that later ) You can see the penetration difference when pipe welding on a open root. A cellulosic electrode like a E6010 will keyhole so you can see the deep penetration

If you weld with both in a open root you can see why the cellulosic electrode is much preferred to a E7018 in real world conditions

Iron Powder

By definition a E7018 must have iron powder. As a result of this you end up with way more weld metal to contend with than a similar size E6010 / E7010

This can causes two problems . Penetration drops because you you cushion the arc and because there is more fluid puddle its really a bad idea to run a vertical down ( most common with API ...cross country pipe welding ). Since there is a larger puddle , if one is not carefull its much easier to trap slag in a root

Easy way to test this is set up a verticle down fillet with both a E7018 and a E6010 / E7010 and run a vertical down. You will end up with a more convex bead with the E7018

Sheilding

A technique with pipe welding ( when using a generator style welder ) is you can long arc / short arc the electrode to vary the current ( even though welder is a CC welder ).

The #1 rule of a low hydrogen electrode is you don't long arc ( or whip ) it

In case anyone was wondering the reason you can long arc a cellulosic electrode ( like E6010 / E7010 ) is as the name implies there is paper in the coating. When the paper burn sit generates CO2 gas, which helps the shielding. Because the shielding coverage is much greater you can pull long arcs without having problems


Low Hydrogen Root Electrodes

Although its not too common here in North America , there are specialty low hydrogen electrodes for open root welding on pipe. They are however E7016s ( like a E7018 but no the iron powder ) This makes the electrode less runny. Having said that typically they are still run VERTICAL UP . Running these low hydrogen root electrodes vertical down like you would a E6010 is asking for trouble

Why a E7018

A E7018 ( actually a E7018-1 ) is often used for in plant ( ASME ) type fill and cap not because the tensile strength is higher ( they make lots of E7018s ) but rather the CVN ( impact properties are far better ....a EXX10 needs only make -20degF impacts, but a E7018-1 needs to make impacts at -50degF ) In addition certain applications require the low hydrogen deposit. A cellulosic electrode is typically 10 times higher in hydrogen content !

[Sberry]

Not that this has anything to do with this but here is a simple 7018 down fillet, use it a lot on sheet when its convenient or dont want to change the machine for a one off joint.

[Jonesy70]

I was talkling to one of the old timers on site today and I asked him why the 7018 root vs the 7010 root vs. the 6010 root...he has worked on this site for 30 + yrs and he has 1000's of welds through out the plant...his expanation was some idiot that nolonger wanted to weld blew several welds and a high strung inspector came up with this solution in Houston, Tx where corprate is. He suggested that I try 8018 for my root. I have never open rooted 8018...I have filled and capped hundreds of joints with it...I was surprised how easy the root went in...then he let me in on a little secret...that is how alot of guys run there roots! I asked about the neet to pre heat with 8018 due to the cromolly content in the 8018? He smilled and asked me to go find a cromolly leaker out in the plant!!
What are your thoughts?