making x-ray welds

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Just looking for people's thoughts on what it takes to make x-ray welds. Particularly I'm talking about carbon steel pipe, tig root and hot, then stick out. Some welders are much much faster than others because they are not so meticulous about fit up, joint prep ect.... Yet they never seem to bust x-ray.   I know that proper fit up and prep are important, but how important? Today I saw two welders side by side making a fit up on 18 in. Pipe. One said "F" it let's tack it , with very little prep, high low it didn't bother him. The other took half the day to get it perfect. They will both pass x-ray  but one guy was done before the other even started. Perfect fit is nice but the reality is, the superstar welder will be there much longer and probably on the next one too. Where do you draw the line on fit up?
Reply:Originally Posted by tiginatorJust looking for people's thoughts on what it takes to make x-ray welds. Particularly I'm talking about carbon steel pipe, tig root and hot, then stick out. Some welders are much much faster than others because they are not so meticulous about fit up, joint prep ect.... Yet they never seem to bust x-ray.   I know that proper fit up and prep are important, but how important? Today I saw two welders side by side making a fit up on 18 in. Pipe. One said "F" it let's tack it , with very little prep, high low it didn't bother him. The other took half the day to get it perfect. They will both pass x-ray  but one guy was done before the other even started. Perfect fit is nice but the reality is, the superstar welder will be there much longer and probably on the next one too. Where do you draw the line on fit up?
Reply:Im pretty easy on fitters,a little hi lo side out alignment okay. Inside needs to be clean! Back an inch or so. Perfect fitups okay for shop, field tie ins diffrent story you need to learn how to weld bad fit ups to pass xray.biggest problem is xray guy being able to read film properly.
Reply:Some inspectors do more than take pictures.  If you have a hi-lo fit of say 1/16th with a 3/8th wall you have created an effective cross sectional thickness of at least 3/8 -1/16  = 5/16 inch.  In some highly stressed members to have that misalignment is of great concern no matter how good the weld.    I have seen inspectors doing a visual get right upset at a misalignment of 1/16th.on structural.  It just depends on the code.  I am wondering what the ASME code says on hi-lo???
Reply:Originally Posted by lotechmanSome inspectors do more than take pictures.  If you have a hi-lo fit of say 1/16th with a 3/8th wall you have created an effective cross sectional thickness of at least 3/8 -1/16  = 5/16 inch.  In some highly stressed members to have that misalignment is of great concern no matter how good the weld.    I have seen inspectors doing a visual get right upset at a misalignment of 1/16th.on structural.  It just depends on the code.  I am wondering what the ASME code says on hi-lo???
Reply:Originally Posted by tiginator Perfect fit is nice but the reality is, Where do you draw the line on fit up?
Reply:every one has the own little way of doing it . dont worry about the others just do your thing (unless your getting bad shots then in that case start looking at the others are doing. some welders are fast and some are slow . some have a fitter that everything has to be perfect some fitters are slam and jam ,put were it fits kinda people. you will see a lot of that .https://sphotos-a.xx.fbcdn.net/hphot...31832359_n.jpg
Reply:Any idea how many years these guys have been welding? I would be willing to bet the guy done first has a few years under his belt. Like most things the longer you have been doing something the quicker you get. Of course there are those guys who just "get it" right out of the gate, but they are few and far between.
Reply:The guys with more experience are definitely faster. What I've seen, is that the welders who backfeed are super fast and can weld just about any fit.  (Tight gap, big gap, it doesn't matter). When I have a gap close up on me, I spend a lot of time opening it back up. These guys just blow and go. I hear all the time, backfeeding is the only way to go. I just haven't gotten it down yet.
Reply:I guess I'm just kinda stuck on the backfeeding thing. I've heard it so much, it seems like the thing to do. I'm not gettin bad shots or anything, just wanna speed it up  a little. Of course I hear that'll just come with time.  Any advice on how to keep a joint from closing up. Last 18 in. I did I went  heavy 1/8 on the bottom and about 3/16 on the top.  By the time I got ,to the top, I couldn't get a 3/32 rod in there. So I had to open it up. Should I quarter it maybe ?  Idk
Reply:It's always better to take your time and do it right than to **** up and have to grind it out.
Reply:Originally Posted by tiginatorI guess I'm just kinda stuck on the backfeeding thing. I've heard it so much, it seems like the thing to do. I'm not gettin bad shots or anything, just wanna speed it up  a little. Of course I hear that'll just come with time.  Any advice on how to keep a joint from closing up. Last 18 in. I did I went  heavy 1/8 on the bottom and about 3/16 on the top.  By the time I got ,to the top, I couldn't get a 3/32 rod in there. So I had to open it up. Should I quarter it maybe ?  Idk
Reply:Originally Posted by justinTYou should always 1/4 your pipe root!
Reply:Weld the top first, one side at a time. That way you don't carry so much heat up all the way from the bottom.I always do this when I need to try to keep a position weld from drawing.