I was wondering if somebody could give me some feedback regarding API Section 19 qualification. It has to do with welding a split sleeve onto a carrier pipe with water circulating through it. The longitudinal seams are to be welded with 7018 open root full penetration. I work for a gas utility and they are adding this test to our 6G 12 inch, and our 12 inch branch saddle. I was practicing running the 7018 on some 6 inch pipe to get the feel of the arc. I tried different gaps and lands, I think I figured out unless maybe I'm wrong that 3/32 land 3/32 root space and 3/32 7018 would work best for this application. I tried holding the electrode straight in the joint and I'm trying to figure out if this is the right way and by dragging it with minimal manipulation it seems a couple times I had to use a slight stepping motion and move slower then with 5P. I would appreciate anyones advice and experience if they could help set me in the right direction. Thanks again I really appreciate it.
That sounds about right. Sometimes a slight "j" motion like a laying down "j" helps just try not to come out of the puddle or break the arc. If the "keyhole" starts to open up on you, push the puddle and go faster.If it closes, pull the puddle and go slower. Takes a little practice but am sure you'll get it. lol revpol
Thanks for your help. I tried this and it seems to be working a lot better for me than it was. I still have a little internal undercut. In some areas of the pipe in the 6G position, in the 3-9 o'clock areas, the root is even protruding about 1/16 to 3/32 above the pipe, and also a little more around the top area of the pipe.
Something seems odd here...how can the longitudinal side seams be considered an open root when the back side of the sleeve is supposed to be in firm contact with either the carrier pipe, or preferably a backing strip? (The backing strip is preferred because it prevents fusion of the weld metal to the carrier pipe). I can't comment on the correct electrode manipulation, but I question the definition of this as an open root.
I am very familar with the 1104 Appendix testing in you describe and how it was developed. The reason for using low hydrogen electrodes is to minimize the probability of hydrogen cracking caused by the very fast cooling of welds that are made onto the surface of the carrier pipe. However, it is really hard to get full penetration into the split sleeve without fusing into the carrier pipe behind the sleeve. Intermittant fusion to the carrier pipe can produce very hard heat affected zones (much like large arc burns) that can crack, despite the use of low hy. A good reason for using a backing strip is that it prevents the contact of the weld metal with the carrier pipe, and therefore, it avoids that potential cracking problem and also greatly reduces the cooling rate of the weld. (Even with tight fit the heat transfer across the backing strip-to-carrier pipe interface is not anywhere close to the heat transfer rate of the carrier pipe itself). It is not uncommon to be able to make crack-free side seams in split sleeves with cellulosic electrodes (i.e., 5P or similar) when a backing strip is used, although I certainly support low hy for any weld that contacts the carrioer pipe directly.
Bill, thanks for your help. Between the people being the engineers at our company and the x-ray hands I spoke to, I agree with what you are saying about the longitudinal seams not being fused to the carrier pipe. When I asked about the procedure after looking over section19 of the API code, they were telling me the company was going to purchase sleeves and have all the weldors tested. They said the joints would be done 7018 open root all the way out. What I related this to was Mueller line stopper fittings where the longitudinal seams bulge, or I should say the fitting bulges and I took this as what they were calling open root. I know as these fittings bulge away from the carrier pipe probably up around 3/4 of an inch maybe more. There's a lot of loose ends with the procedure that wasn't clear to me and even some of the other weldors that weld for our company. I really appreciate your help. Thank you again. Paul
Use the downhill E7048 (low hydrogen) or if that is unavaible. Use a high hertz ac from an engine drive like Miller Electric Trailblazer or Legend. It has a 120 hertz ac versus the 60 hertz most other machines have. Ac is the preferred, you don't need the special ac 7018 electrodes. If that is not an option use dc electrode negative and then hot pass and out with electrode positive.
I don't have access to an AC machine, but me having an open mind I am going to try out straight polarity like you spoke of. On my own I have used Lincoln's LHD-80 (8018-G) the downhill low hydrogen electrode, but the only problem is the company wont recognize it. Thanks again for your help. Paul
just an FYI, we use LHD90 for in-service welding when our FCAW guys are unavailable and the conditions require the use of low-hy. Our guys would rather run LHD90 than to learn how to do SMAW uphill. The only negative comments we get is that there is some susceptibility to pinhole porosity on the cover pass. We did a bunch of 12" butt welds with the LHD90 for hot, fill and cover in a situation where we needed very high butt weld strength and good toughness.
Paul, I wish the powers that be, would have the professional and technical wisdom to present a written procedure concerning your process. I believe this would eliminate the gray areas.
You're right. The other gray area it would help eliminate would be on top of my head. I called down to the engineers today, the x-ray company had a weldor in New Jersey, weld a procedure. I received the message that the coupons were cut and that everything passed. Our company is supposed to adopt the procedure. I requested a copy of it. So maybe soon, or I'll keep calling down until I wear the ringer out on their phone. I also told my superintendent how serious this is and me being the company weldor to please help me out getting this. So we'll see. Sorry for whining and thanks for everything. Paul
In our company I'm the guy that writes new procedures. If we were starting a new practice that we had not done before, let's say for example running a E7018 root, I would be working with the welders and trying different techniques (DC, AC, technique, etc.) before committing the procedure to paper. That seems to result in better acceptance from welders compared to Engineering just delivering a new procedure based only what they read or get from consultants. (Of course you can minimize the time spent tinkering on the procedure with the welders if you do the homework and check all available resources and references before you strike an arc.) New procedures are best developed in a collaborative manner.
Bill, I agree with you 100%. This is the point what you are saying that I am trying to get across to these people. I have no problem with them consulting with other people, but like you said the weldor should especially have a right to be informed because he is the one going to the wolves. Thanks Everybody For Listening And Understanding.I Appreciate The Feedback. I'll let everybody know that helped me through this how I make out. And like I said Thanks Again. Sincerely Paul
Paul, you know where you can practice! Relax....Mark and I both know you won't have any trouble passing the test. You're the man! (guess who)
Fran, I have to pass. Ha Ha, Do you know how I'd feel not being able to weld on a live line? My heart would be broken. I'd miss roasting hot dogs. Thanks For The Pep Rally. Paul
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