High pressure welding test

being a newbe welding and trying to learn something, I contacted the local
welding school to know more about the high pressure welding exam.
Here in Quebec, Canada, it seem that the labor departement of the provincial
gouvernement is responsible for these test. I contact them and they sent me
the procedure.
The pipe is schedule 160, 2 inches nominal diameter (0.343 tickness)
The welding position is 6g (45 degre)
The root pass should be 6010 or 6011
All other pass should be 7018 or 48018
The weld should pass a radiographic exam
I know that the best way to learn is thru school, but I want to try, just
for the fun of it. I now have the pipe to practice, but need to know some
other things:
wich electrode should I choose, and why?
what is the appropriate current for each electrode?
what is the radiographic exam ?
I understand this is some kind of film that is turned around the weld and
exposed with "rayons x",
but what is the resut. Does it check the porosity. If there is porosity in
one layer, but no porosity in another layer, what will we see with the
radiography? To fail the test, do we need porosity, on every layer, at the
same place?
Thanks for any help.
PS: excuse my poor english, it's second language for me
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If it was that easy high pressure welders would be working for less than Wal Mart wages.
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Your preparation of the joints is half the job. The electrode selection is obvious for someone who has done some reading. I suggest you purchase some welding texts. I am not sure if there is a french version of "Modern Welding". The E 6011 in Canada is a E 41010, a cellulosic rod. The first pass or root pass is done at a relatively low heat to avoid grapes on the inside. It is odd that the second pass is not a hot pass with the cellulose rod also. The following passes are done with a low hydrogen electrode in order to limit hydrogen cracking. E 7018 or E 48018 The radiographic inspection sees all. Any porosity unless very minute will be a failure. It will also see any slag inclusions and sometimes even cold laps. You should concentrate on make perfect beads on flat plate. After that on vertical plate and then overhead. Only then should you start to practice on pipe. Randy
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Randy Zimmerman
Does that mean that you think I should not try it (the exam)? and you think that I should not even try it with my scrap piece of pipe. What can I lose? I have more than enough time on my hands in winter to practice (I do landscape / excavation in summer, snow removing when it snow during winter)
I know it's not that easy, I did work last summer on a job where they welded 16 inches steam pipes. Extremely nice welds, all around the pipe.
But instead of practicing on any steel, why not on pipe? :)
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Thanks for the answer Randy
I have 2 books: welding essentiels and the one I just start reading, new lessons in arc welding from Lincoln
Just one more question: wich size electrode should I use for 0.343 wall tickness? My welder is a Ranger8, so that limit me to 200-225 amps. I really want to try on that pipe, even if it's only to realize how hard it is
Thanks again
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Bevel the edges of both pipes to 37 degrees to give you an opening of approx. 75 degrees. The gap should be around 1/16th . Tack weld in three places. For your first pass try E 6010 or E 6011 1/8th diameter at around ninety amps electrode positive. The bead inside should stick into the pipe no more than 1/16th of an inch.
Reply to
Randy Zimmerman
Local trade based Community Colleges and University have well stocked libraries and book stores that are a great source of up to date books on welding and other trades. I don't know about Quebec but in Ontario some Colleges and Universities even let non students borrow books from their libraries.
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Get your pipe and get it set up and practice, practice, practice. Look at the bead, if you don't like it, do it over. If YOU don't think it looks good chances are it isn't. I used to tell all the helpers I had that wanted to be welders "you will only be as good as you want to be.' Meaning if you put in your time to learn this trade, it will take care of you for many years. It is as the others stated, it is not an easy test. Here where I am in California we take it every year on the T&M work and almost always take a test of sorts for the hard money jobs depending on what the customer requires. The x-ray portion shows up all of your flaws. If they are within certain limits they may be allowed, if not, you will fail and not get the job. All of them and their standards are suited to their needs and specifications. We take the test you are describing with a 6010 bead and hot pass and 7018 out. We can single or strip cap, your choice. ASME B31.3, API STD. 1104, or ASME B31.1 are the main criteria for most of the work that I do, which includes pipelines, steam or production and food processing.
I would not, however, try it one time and then take it down and have it tested. Chances are you will be wasting money. There have been a lot of welders that travel for 2 or 3 days to take a test, and then fail it and turn around and go back home. Their livelihoods rest of how well they do so we do not take tests lightly as I feel you are. But even so, everyone on here knows there are welders and there are welders. Meaning welders that know how to burn rod and welders that can do it all. You need background.........as in experience....good luck, BUT practice, practice, practice.
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You would be better off using bar stock set at various angles so you can get each one right. On pipe the angle changes as you go around it.
Francois wrote:
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What you are considering attempting is a very difficult test: open groove on small diameter, thick wall pipe in 6G. This is the kind of test that most professional pipe welders sweat over when they have to take it. I doubt any newbe will be able to pass visual inspection much less x-ray if you just jump into it. Even if he does pass visual, I can just about guarantee you will see every flaw including porosity, inclusions and lack of fusion in the x-ray.
I recommend you save the 2" pipe for later. Concentrate on producing sound fillet welds on plate in all positions including vertical and overhead. When you can do that well (pass visual inspection and a bend test), go on to open groove welds on plate with a backing bar in the same positions. When you can do that well, go on to open groove welds on plate without a backing bar. When you can do that well, move on to pipe.
Start your pipe practice with something reasonable, say 8" or 6" pipe with around 3/8" wall. You want something thick enough to be able to do a root pass, hot pass, at least one filler pass and a cover pass, and large enough that you can ease into constantly changing your angle. Do 2G (pipe fixed in vertical position) and 5G (pipe fixed in horizontal position) welds until you can do them well. Then do 6G (pipe fixed at 45 degree angle). Work your way down to the 2" pipe.
The Horbart Institute has a whole series of books on plate and pipe welding that explain the techniques used. Absolute best book on pipe welding is Pipe Welding Procedures, 2nd Ed. by Rampaul. First edition will do if you just care about stick welding.
If you have a DC machine, use 6010 for the root, otherwise 6011. My guess is that you will have to use 1/8" electrodes on the test. But check with you provincial government to make sure. It used to be traditional to follow the root pass with a hot pass using the same electrode. Now some procedures are calling for the hot pass on a 6010 root to be done with 7018. Find out what the test will use. But practice hot passes with both electrodes.
The x-ray test isn't concerned with layers. There will be criteria specifying the size and quantity of defects. Stay under and you pass. Go over and you fail. Although you didn't mention it, there is bound to be a visual inspection first for excess reinforcement, undercut, underfill, suckback, lack of fusion, overlap and porosity. Fail visual and you don't even get to x-ray.
Check with the provincial government to see what the fit up should be. Otherwise use a 75 degree included angle for the bevel (37 1/2 per side), 1/8" gap +- 1/32", 1/8" land +- 1/32".
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