Hi
The answer to your query is that the SS316L plates used for shell fabrication shall be in solution annealed condition. No PWHT required. Regards Prem Nautiyal
--- On Mon, 5/9/11, lassaad mokrani <lassaad.mokrani@gmail.com> wrote:
From: lassaad mokrani <lassaad.mokrani@gmail.com>
Subject: Re: [MW:11003] RE: 10941] SS316L PWHT
To: materials-welding@googlegroups.com
Date: Monday, May 9, 2011, 3:25 PM
Many thanks Mr.Pradip, Just one thing, i 'll follow the steps enumerated below: Solution Anneal the dished head ,as proposed. Check hardness (especially in knuckle radius) following solution anneal to conform to 22 HRC max requirements. Check hardness on the shell (preferably on the L.S and adjacent BM, HAZ) to ensure that recorded har Does the last step means that we don't need to solution anneal the shell??. My understanding of solution annealing is that this last is equivalent to PWHT, isn't it??
Please advise
Best Regards,
MOKRANI Lassaad Project Manager EPPM-Tunisia 00216 20 649 755
2011/5/8 pgoswami <pgoswami@quickclic.net> Hi Morkani, The formula for calculating strains as per UHA -44 are as follows. Generally the strains level in a dished head (especially in the knuckle area) are more than in the shell, that's why many clients call for post forming HT in the dished heads. In absence of NACE MR -0175 requirements , UHA -44 would apply to determine the requirements of post forming HT requirements .In your case MR-0175 applies , in addition there may be some client's requirements also. If you see the requirements of MR-0175, Table A-2 specifies austenitic S.S(S.S 316) shall be solution annealed, free from cold work and has hardness less than 22 HRC.The second clause has a catch, as any dished head will be strain hardened if cold formed ( which may be applicable in this case). Once strain hardened, then hardness could increase depending on original hardness level and degree of forming.This could be minimized only through solution anneal. However for a dished heard of thickness of 12 mm , unless properly supported there may be distortion on solution anneal. As mentioned by you below and my understanding of the problem the following shall be done. -
Solution Anneal the dished head ,as proposed below. -
Check hardness (especially in knuckle radius) following solution anneal to conform to 22 HRC max requirements. -
Check hardness on the shell (preferably on the L.S and adjacent BM, HAZ) to ensure that recorded hardness is less than 22 HRC. I would think doing all the above would ensure complete diligence. Thanks. Pradip Goswami,P.Eng.IWE Welding & Metallurgical Specialist & Consultant Ontario,Canada.
Thanks Mr. Pradip Yes, our design code is ASME VIII Div 1. As i understood from your answer and since the two conditions indicated under UHA-44 are not rreached: 1-Design temperature (-15°C-65°C) less than 676°C as per table UHA-44 2-Strain limit is less than 10% when calculated as per cylinders fromed from plate formula Therefore we don't need PWHT only for dish ends. Am i right??? Please confirm urgently
MOKRANI Lassaad Project Manager EPPM-Tunisia 00216 20 649 755
2011/5/5 pgoswami <pgoswami@quickclic.net> Hello Mok, MR-0175,Table A.2 specifies Environmental and materials limits for austenitic stainless steels(including S.S 316) used for any equipment or components. The requirements are:- -
be in the solution-annealed and quenched, or annealed and thermally stabilized heat-treatment condition; -
be free of cold work intended to enhance their mechanical properties; and -
have a maximum hardness of 22 HRC NACE does not have anything mentioned on post forming strain and teat treatment. If the design code is Sec-VIII, DIV-1, then look under table UHA-44 for "POST FABRICATION STRAIN LIMITS AND REQUIRED HEAT TREATMENT" as a function of design temperature. I hope this would help to clear the doubts. Thanks.
-----Original Message-----
From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Mok
Sent: Wednesday, May 04, 2011 11:31 AM
To: Materials & Welding
Subject: [MW:10941] SS316L PWHT
Dear All,
We are fabricating two vessels in SS316L (thickness 12mm) diameter 794mm each to be used as fuel gas separators. We have tried to convince our client that we don't need any PWHT for the shell, since the strain doesn't exceed 5% and that NACE MR0175 doesn' oblige that.
We decided to make the PWHT only for the dish ends.
But our client insisted to do it anyway for the whole vessels.
I need your input urgently
Best Regards,
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-- Meilleures salutations Mokrani Lassaad 00216 20 649 755 http://www.linkedin.com/pub/lassaad-mokrani/16/364/907P Pensez environnement! N'imprimez ce mail que si c'est vraiment nécessaire Please consider your environmental responsibility before printing this e-mail This e-mail is confidential and it is intended only for the addressees. Any review, dissemination, distribution, or copying of this message by persons or entities other than the intended recipient is prohibited. If you have received this e-mail in error, kindly notify us immediately by telephone or e-mail and delete the message from your system. The sender does not accept liability for any errors or omissions in the contents of this message which may arise as a result of the e-mail transmission -- -- Meilleures salutations Mokrani Lassaad 00216 20 649 755 http://www.linkedin.com/pub/lassaad-mokrani/16/364/907P Pensez environnement! N'imprimez ce mail que si c'est vraiment nécessaire Please consider your environmental responsibility before printing this e-mail This e-mail is confidential and it is intended only for the addressees. Any review, dissemination, distribution, or copying of this message by persons or entities other than the intended recipient is prohibited. If you have received this e-mail in error, kindly notify us immediately by telephone or e-mail and delete the message from your system. The sender does not accept liability for any errors or omissions in the contents of this message which may arise as a result of the e-mail transmission -- To post to this group, send email to materials-welding@googlegroups.com To unsubscribe from this group, send email to materials-welding+unsubscribe@googlegroups.com For more options, visit this group's bolg at http://materials-welding.blogspot.com/The views expressed/exchnaged in this group are members personel views and meant for educational purposes only, Users must take their own decisions w.r.t. applicable code/standard/contract documents.
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