SEAM PIPE
SEAM PIPE
(OP)
Why circumferential seam is not allowed in manfacturing of welded pipes?
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RE: SEAM PIPE
RE: SEAM PIPE
circumferential welds are much more sensitive to stress than longitudinal ones and need much more NDT.
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RE: SEAM PIPE
Circumferential welds are not more sensitive to stress than longitudinal ones if the main loading is internal pressure!!!!
RE: SEAM PIPE
I would presume that circumferential joints are not permitted in the manufacture of pipe because if I order a length of pipe, I don't want to receive a series of 3' long pieces from your scrap bin welded together!
RE: SEAM PIPE
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: SEAM PIPE
http://pipingdesigners.com/contents/blog/130-blog-...
"suren12564", Where did you hear or read this statement:"circumferential seam is not allowed in manufacturing of welded pipes?".
Longitudinal Seamed Pipe is purchased in single random lengths, double random lengths and coil lengths.
This pipe is cut to required lengths and then fabricated into configurations called spools for assembly at the jobsite. These configurations contain lots of circumferential weld seams.
Sometimes its possible to do all the right things and still get bad results
RE: SEAM PIPE
As moltenmetal says "you do not want a random length of pipe being supplied bu welding a number of offcuts". I know pipe may be supplied with a circ weld but from my point of view one circ weld should be the maximum. Fabricated pipe spools are different to pipe from the mill.
RE: SEAM PIPE
If I order a 6 mtr length of pipe I should not receive 2 x 3 mtr lengths welded together.
It is hard enough to get an MTR out of some mills - what do you think the chances are of getting a copy of the WPS (copy of the PQR to support the WPS), copy of the Welder Qualification Certificate and a copy of the NDT report for the circ weld ?
RE: SEAM PIPE
RE: SEAM PIPE
RE: SEAM PIPE
RE: SEAM PIPE
There is even a specific appendix for welded jointers.
Personally I wouldn't agree to it coming from a vendor and have never seen it on a pipeline supply.
Welding DJs in a yard or load out facility yes, from a pipe mill, no.
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RE: SEAM PIPE
RE: SEAM PIPE
There had been cases where the UT device that was used to confirm correct weld quality was incorrectly calibrated, and a whole batch of seam welded pipe was shipped and used with defective seam welds. And there have been major accidents involving seam welded pipes that failed in the creep regime ( Mohave 1986- 11 deaths) . So there is a reason why some codes do not permit seam welded pipe .
"In this bright future, you can't forget your past..." Bob Marley
RE: SEAM PIPE
It's like throwing in a dime in an old jukebox which starts rattling on and on ...
RE: SEAM PIPE
... it's not over until the fat lady sings.
RE: SEAM PIPE
Makes more sense economically to have the mill make the double end welds and have them radiographed to the appropriate Code. Lower transport, handling and middle man profit costs are achieved as well as potential lowered owner inspection costs. I've done this on cross country pipelines and stainless steel cryogenic pipelines where full inspection was done at the mill by Owner/Engineer.
RE: SEAM PIPE
Welding the joints is an extra activity for the mill and only makes sense if the welder costs are a lot lower than they would be at a pump dump.
XL83NL - Agree with you 100%
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.