I work in a refinery & look after, among other things, in
repair/rectification & new fabrication jobs.
Especially in piping jobs, we do use old pipe fittings after salvaging.
Our working philosophy is like this -
For new fabrication jobs - always use new fittins. For replacement jobs - salvaging is acceptable.
The rationale behind this philosophy is not very clear to us either.
We use almost any salvaged fitting. We have Quality assessment policy regarding use of this. ThatQAP includes, among other things, a DP test of the edges of fittings to ensure that no crack generated during gas cutting etc. Crack generation sometimes observed specially when the fittings are quite old & thickness is high. And our salvaging is not always restricted to CS only. We have salvaged many alloy steel and SS fittings too.
Metallurgy wise, there has been very few problems faced if salvaging procedure was ok.
'Hope it helps
Regards
-----Original Message-----
From: <a href="/group/PipingDesign/post?postID=-7KT5eFFR7ogqFFHpWFnoU_Ml6B2lwWf-dlq4G_TQEEVM2-zxqut_keNv0Lu481joPWzCfqjFw1MxarKZBo2hFbeM1dYdw">PipingDesign@yahoogroups.com</a>
[mailto:PipingDesign@yahoogroups.com]On Behalf Of aluser2
Sent: Friday, September 02, 2005 3:42 AM
To: <a href="/group/PipingDesign/post?postID=-7KT5eFFR7ogqFFHpWFnoU_Ml6B2lwWf-dlq4G_TQEEVM2-zxqut_keNv0Lu481joPWzCfqjFw1MxarKZBo2hFbeM1dYdw">PipingDesign@yahoogroups.com</a>
Subject: Re: [PipingDesign] Metallurgy
its a good question with no easy answer. I too would share your concerns,
but given that weld repairs are done frequently and the practice of reusing
welded fittings does happen i beleive one can do it.
I think the key is for the person taking responsibility to have a REALLY
clear picture of the service and what they are doing .Problem is one often
doesnt have control or ability to ensure execution all the way through to
ensure the re-use is properly handled at all steps.
What is being re-used and how it is being re-applied. one would need a
guidelist of do's and donts. clearly in the donts
- critical service
-high temp/ low temp
-pipelines or anything buried or becoming inaccessible for alter ndi and
monitoring
-something damaged , questionable prior service eg previous hydrogen or
sour service
- is the documentation for the product available, MTR's etc. not often
likely
could go on ad infinitum....
sorry ,but its such an open ended question its hard to answer better. The specifics become really critical.
> Hi guys,
>
> Does anybody know about the advantages and disanvantages of re using
carbon steel pipe fittings such as o-lets for piping system modification.
I'm concerned about the effect on the metal microstructure changes for
fittings welded for the second time. If you can refer me to any paper which
pertains to this matter, I would greatly appreciate it.
>
> Cheers.
>
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Yahoo! Groups Links Received on Fri Sep 02 07:10:00 2005
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