Trouble with my TIG

admin

Hey guys I'm new on here. I just started TIG welding not too long ago. But for some reason I got 7 reports on 2" carbon steel pipe. And on all of them it was the same thing one pin hole? When I went back to fix them I couldn't find anything? Does anyone know why this might be happening? Checked my gas lines and even switched booths. Thank you
Reply:What type of tests are these? Open root, consumable insert?What position are they welded in?  Are they done in a restricted area booth (12"x12" x6")?How are they tested...xray, LP?Any more details?Rich
Reply:Sorry bud 2" butt weld open root. They are being rolled out all the way. Booth is about 7'x15'. And yes everything is being x-rayed
Reply:So, the xray showed 1 pinhole in 7 different tests?When you tig weld, are you using a hand held pot, or a foot pedal? In either case, when you are going to stop welding for any reason, you have to decay out, or down slope out. You can't just stop. If you do, you may get a crater pit. These can appear as a pinhole on an xray.It' very unlikely that you'd just get 1 pinhole all the time for any other reason. I don't like xray because it's very subjective...it's all in the interpretation of the reader.I'm a pipe welding instructor, and our butt joint tests have to pass xray. We have several film readers, but one reader rejects almost every test for 360 degree lack of fusion.THAT'S NEARLY IMPOSSIBLE!!We use consumable insert rings. If the ring is pulled, which we can see that it is, there's no way that there can be 360 degree L.O.F.So, I'm not fond of xray...So, make sure that you slope out gradually.On steel pipe, we use a 6 second decay, down to 3 amps before shutting the torch off.Rich
Reply:As I'm welding through out the whole way I always go past my stopping point a bit more. And usually grind a bit just to be on the safe side. And yes it is literally one pin hole on all of them. And the rest of my weld have been shooting just fine. Im asking if there's anything else I might be doing wrong because they already asked me to keep an eye out for that. No foot pedal Root 1/8 rod at about 771/8 rod for hot pass and filler at about 95 and cap at 100
Reply:Thanks for the help bud
Reply:Hi. Steelsurgeon is correct in his statement. Ok you say you go past your stopping point but that isn't what steelsurgeon is saying.When you terminate the arc the weld cools very quickly which can cause a pinhole. With a pedal or torch dial I would finish by bringing my amps down gradually from say 100 amps to 10 or 20 amps.But you don't have remote amperage. Most modern machines have a slope down function which you can set so that when you finish it will slop the arc down.If your machine does not have this function then I would suggest the following...When you release the trigger to finish your weld hit it again a few times so that the arc goes on and off. This enables the weld to cool at a slower rate thus preventing the pinhole.Hope this helps
Reply:You're using 1/8" filler rod on a 2" pipe? And what wall is the pipe?Are these tests open root? Do you have to follow a technique sheet?I ask a lot of questions mostly because I'm a curious kind of guy, and like to compare what the rest of the industry does, vs. the way we have to do things.Rich