Don't think that a successful PQR leads always to successful production welds. Do not forget that sound engineering judgement us the first consideration. Therefore I would suggest to use an intermediate low alloy in order to avoid PWHT temperatures which do not are in conflict with lower transformation temperatures
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| From: Chandrakant Vaidya Sent: Πέμπτη, 31 Δεκεμβρίου 2015 - 09:37 To: Materials & Welding Reply To: materials-welding@googlegroups.com Subject: [MW:24018] Re: PQR - WPS - PWHT P91 to CS |
Greetings.
In my view the CS temp.attachments can be welded with Gr 91 mtrl.but not job mtrl.as rightly stated by Pradip & Zakeria.
Regards
C.L.Vaidya
On Saturday, October 20, 2012 at 3:59:03 PM UTC+5:30, Tunisian Quality Engineer wrote:
On Saturday, October 20, 2012 at 3:59:03 PM UTC+5:30, Tunisian Quality Engineer wrote:
Dear experts,
Need your support.
We performed one PQR P91 grade ( P number 15E) to Carbon steel (P number 1) welded GTAW/SMAW ER90S-B9 / E9015-B9, 11mm thickness, PWHT @ 740°C - 40 minutes.
PQR and related WPS already approved by our client. but the Owner consulting agency sent to us some comments :
1- No possible to weld P91 directly to CS shall add transition material P11 grade : We answer that it's design issue and i requested some explain / calculation from design.
2- Should use filler metal compatible with lower grade material : i answer that can make choice of filler metal between to material grades (included) so we can weld with lower, heigher or iontermediate filler metal when mechanical properties is ok and don't have ebjection from project spec.
3- this is the main issue : PWHT @ 740 °c is heigher than lower critical temperature for CS so we must perform PWHT in intermediate Temperature : in this case if will do like this WPS will not supported by Prepared PQR;
PQR approved by Client and weld already done, i propose to perform hardness test, PMI and metallographic replic in production ( just one weld) to confirm.
Need your support .
Regards.
--زكرياء غراب
GHRAB Zakaria
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