Hello R Mitchell, I wouldn't say that it isn't acceptable. Instead I would say that it requires a higher level of skill to perform than other electrode selections might. Yet, when I was originally training a whole lot of years ago, I was always told that it would require a backing strip due to the perpensity for pinholing from not having proper slag coverage on the backside of the plate. Having just said that, this practice is used extensively out in various parts of industry these days. There is also the matter of position and joint fit-up. E6010 and similar electrodes, due to their make-up and characteristics, are better suited for open-root applications. You can vary the arc length more effectively to deal with poor fit-ups and without risking root discontinuities or failures much more readily than the E7018 will allow for. These items would be a description from my perspective to answer a portion of what you are asking, likely others will have additional opinions. Best regards, aevald
aevald,
Thanks for the reply. I have thought myself what you have said but recently attended a seminar for CWI testing and was told no by several of the attendees. My welding generally is on heavy equipment for full - pen welds and so forth.Lets test your memory, do you remember at
end of last
year and the first of this year, I asked about Young Boom troubles? You and I talked quite a bit. I have another question about testing posted and I would appriciate your input if you dont mind.It is titled in house testing D1.1 structural SMAW & FCAW
Hello again, I do remember some of our conversations from then. I am not so good with the interpretations for specifics of codes, a little better possibly on the technical issues of various welding processes. I do recall instances where welding tests were conducted in-house and then the specimens were packaged and shipped to another facility for RT. The part I don't recall is how all of this was tied together in the way of paperwork. On some PQR's you will notice the different signature lines, I believe in some cases the "test witnessed by" can be signed by you and the "test conducted by"(possibly the lab that conducts the bends or RT) can be signed by them signifying acceptance of results. I'm sure there are others here that can answer your question way better than I can. Best regards, Allan
By Kix 
Date 11-06-2008 20:02
Edited 11-06-2008 20:07
7018 and 7016 open root is acceptable for certain applications and is done mostly in piping. It is actually more common them most people know about and requires a good bit of skill to make it work like said above. The 7016 is supposed to have been designed specifically for low hydrogen open root. I like to run my 7018 open root on A/C and in my opinion, it is the most consistent way to go about it and still get good mechanical properties. Some people also run it straight polarity, but porosity is more common with this polarity if your not careful. It is mostly run in reverse polarity because that's what most WPS's were qualified in (not many people over here have been told to run it A/C and have no experience wit it). 7018 A/C is very common over seas and it works let me tell ya. Don't use a 7018 A/C rod, just use a regular old 7018. 3/32" Lincoln Excaliber is the best rod for this application. I tell you this from experience. I've used 7018's from all over the world and found the Excaliber to be the cadilac of 7018 open root. Hope this helps to answer your first question.
Puttin a root in with a lohy rod will not be learned overnight thats for sure, it takes a highly skilled pipewelder to do. The fitup and joint prep is critical.
I have used them but prefer a 6010 or 6011. 7015 or 16 may work too.
There may be cases in which codes or project specifications prohibit non low hydrogen electrodes or require special precaustions/controls (Preheat Elevated).
The reason they are more difficult is because the molten metal freeezes slower and thus has more time to sag/fall. Thats just an opinion.
Also, look at your contract documents before using 60 series. If it's a structural application, specs. typically require 70 series electrodes because that's what the weld design calcs. are based on. If that's the case, you'd need EOR approval to use it.
I have heard of some guys using 7018 on AC for root pass applications. 7018 is not commonly used for open root welds, so many people think it can't be done. However, someone with a high skill level could possibly do it given the right circumstances. KIX, is a regular forum user here, and has quite a bit of experience with this. He might be a good person to bounce the question off.
Do a search on the forum on open root 7018. This has been covered several times. Open root 7018 is done every day in piping. It just takes a weldor to do it.
BABRT's
A weldor or a welder? there's a difference you know. ;-) Not sure what it is but I heard there was. Not sure which one I am yet.
Im a weldOR. I can weld OR Grind!
:-) OR stay in the truck till it's tme to come out and weld.
Anybody can operate a welder, but not everybody can be a weldor. :-) Old school
jrw159
So an open root on pipe with a 7018 you have to have a pretty tight gap then don't ya? So as not to burn through but be able to pause long enough to get good penetration? When you bevel it would it be good to have a land and not a knife edge bevel?
no pausing with lohy open root.;-) If ya do u'll either blow through or hang a stalag tight in the pipe. Yes, you want to have a land, ruffly 3/32" and a sloppy 1/8" gap. Like said above reseach this topic and you will find loads of info.
I learned to weld open root pipe with E7018. The test was two inch, schedule 80, in the 6G position. All progression was vertical upward.
Once I passed the open root with E7018, I was trained and tested using GTAW open root with E7018 fill, again in the 6G position.
I learned to use E6010 on open root with a different company with different welding procedures. That's the name of the game, every job requires you to learn something a little different than what you are used to doing.
Best regards - Al
I don't know why it wouldn't be. I've taken an open butt tube test .625" wall with 7018...funny thing is their company welders had 6 weeks to practice for the test and when myself and another guy hired in we were thrown into the fire so to speak...whatever rod diameter you have...make the land 1/2 that. Same way with root opening. It only gets tricky when the nuclear procedure allows root opening to be +/- 1/32" of rod diameter. You really have to be good, and yes you can push the bead to the back, but it's like walking a razor edge from welding the tube or leaving caveman tools in the ID.
