I am about to take a test on 6" schedule 40 pipe in the 6G position. This normally would be my favorite weld, BUT I am used to doing an open root with 6010. For the test I will be welding with a backing ring. I have never seen a backing ring, let alone welded on one. the test will probably be tommorow morning, so I do not have time to find one to practice with. I told the guy giving the test that I had not welded with a backing ring before and all he said was "It is easy, keep the heat on the pipe, Now, if you do blow through the backing ring you do bust." Can anyone give me more info than that? He said the ring has prongs.. how do you tack it? Is there a good heat i should run the root pass at to reduce my chance of blowing through? should I do small circles with stick to tie in the bevels and the strip,or should it be more of a straight pass? I don't know how thick the backing ring is. I was told it would be a 3/32 7018 root and fill and a 1/8 7018 cap. would prefer 3/32 all the way out, but that should not be a problem. Any help you can give would be greatly appreciated!!
thanks again,
Mike
backing rings make life easier. I'd set the heat to a medium level considering you'll be welding overhead (requires more heat) and vertical up (requiring less heat). I like to center the rod directly over the toe of 1 pipe and then move over to the toe of the other pipe. that way you know you'll get good fusion into the toes and into the backing ring. also, by doing that you reduce the chances of burning through the backing ring. if done correctly and at the right heat the bead will look flat or concave. if it looks convex, you might be moving too slowly, or you're not pausing at the toes, or the heat is too low. and if the bead is convex, check for slag inclusions along the toes of the weld by visual inspection or grinding. have fun and good luck!
Take a look at www.robvon.com to find out about other applications for backing rings.
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