Welding of flanges to Stainless Steel

admin

Hello allI'm looking for some guidance/advice on a problem that I may have.I have a pipe fitter installing some rolled stainless steel pipe (60No x 3Metres); the pipe was manufactured to an acceptable Standard under a Quality Management System the pipe was then taken to another country and had stainless collars welded on for slip flanges.I do not know under what controls the welds were made, although visually they look very unifrom.What checks should I be requesting?Some background; the pipe will remain at 1bar normally but in use will reach 4bar in 0.1 sec. The pipe temperature, in use, will go from ambient to -100F in 0.5sec. The pipe is 250mm Diameter and is 6mm thick steel.Any help is appreciated.
Reply:And you took this all back without some sort of inspection report??Send it off to who knows where to have such a process done without prior knowledge of said company?Now ask us for an answer????????Secondly..You post this then sign out before getting some sort of answer..Ambient to -100 F in 1/2 second??Something smells fishy here...How the hell do we know if this is even real?Pics would help...If you can find them.....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:1)slip flanges...? van stones?2)you are talking some severe stresses to this pipe. id say you need to do some real conditions testing, 50% over what you expect to experience..
Reply:Since the welding is done out of country, and out of sight, the only things you can do are : #1 Request a specific welding process that YOU spec out and approve be the one used. #2. Obtain samples of test welds before production starts, and have the test welds cut into coupons and have them tested. #3. X ray sample welds; you will be able to see the continuity of the weld to be assured of the welders following the protocol. #4. Hydro test the welds before putting them into service. That's how we do it when the welding matters in an industrial world.And then, after so much work...... you have it in your hand, and you look over to your side...... and the runner has run off. Leaving you holding the prize, wondering when the runner will return.
Reply:When I read "ambient to -100deg in .5 sec" I knew I was out of my league.His too, I suspect.Syncro 250 DX Dynasty 200 DXMM 251 w/30A SG XMT 304 w/714 Feeder & Optima PulserHH187Dialarc 250 AC/DCHypertherm PM 1250Smith, Harris, Victor O/ASmith and Thermco Gas MixersAccess to a full fab shop with CNC Plasma, Water Jet, etc.
Reply:Hi Keith, and welcome!There should be at least a little paperwork around, inquiry, purchase order and WPQ if the work is critical.Is this the accumulator dump circuit on the second stage of a really big cascade cooling system? R-503 is something like 60psi at -75 but if something goes wrong can reach up to 700psi if not allowed to go to vapor on shutdown.Matt
Reply:Just as I suspected..No response from the OP...I smell a troll.....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:Originally Posted by zapsterJust as I suspected..No response from the OP...I smell a troll.....zap!
Reply:Originally Posted by sn0border88Would it hurt you to give him more than 24hrs to respond?To try and help the OP you should certainly be able to track down a WPS for the spools.  If not, then you need to have a talk with whoever contracted out the work.
Reply:Originally Posted by zapsterWhat is going on here?...zap!
Reply:Originally Posted by sn0border88Your age is getting the best of you.  Look again.
Reply:Originally Posted by RojodiabloSince the welding is done out of country, and out of sight, the only things you can do are : #1 Request a specific welding process that YOU spec out and approve be the one used. #2. Obtain samples of test welds before production starts, and have the test welds cut into coupons and have them tested. #3. X ray sample welds; you will be able to see the continuity of the weld to be assured of the welders following the protocol. #4. Hydro test the welds before putting them into service. That's how we do it when the welding matters in an industrial world.
Reply:Originally Posted by Matt_MaguireHi Keith, and welcome!There should be at least a little paperwork around, inquiry, purchase order and WPQ if the work is critical.Is this the accumulator dump circuit on the second stage of a really big cascade cooling system? R-503 is something like 60psi at -75 but if something goes wrong can reach up to 700psi if not allowed to go to vapor on shutdown.Matt
Reply:Originally Posted by RojodiabloSince the welding is done out of country, and out of sight, the only things you can do are : #1 Request a specific welding process that YOU spec out and approve be the one used. #2. Obtain samples of test welds before production starts, and have the test welds cut into coupons and have them tested. #3. X ray sample welds; you will be able to see the continuity of the weld to be assured of the welders following the protocol. #4. Hydro test the welds before putting them into service. That's how we do it when the welding matters in an industrial world.
Reply:Originally Posted by Mr Keith ThomsonMuch appreciated; I'm in the fortunate position that it's early enough in the process to challenge this.RegardsK.
Reply:And, FWIW... I'd be doing a hydro test and x ray on 100% of these lines, for a CYA.And then, after so much work...... you have it in your hand, and you look over to your side...... and the runner has run off. Leaving you holding the prize, wondering when the runner will return.
Reply:Thank you; this moves me on; I have already moved forward on the insulation as intuitively I felt that the differential expansion could be a problem.Currently I have been in touch with another facility with the equipment in use, to find that they were unaware as to whether this issue had been raised as it was all organised through a Design Team; my current Design Team has never been asked this question before.To be honest I probably would never have questioned the welds had they been factory made.RegardsKeith