Hi,
PWHT (for SR) holding period at the appropriate temp should be as low as possible so that Cr-C does not get much chance to precipitate out. Please refer to a metallurgist for any good solution annealing procedure. Though its purpose is different, the functionality is almost the same. As per my past experience, the job is held at a temp outside the sensitization range till temp gets stabilized, then quickly quenched in a few seconds to below 300 deg C by immersing it in to an iced brine solution (if at 800 deg C or so) or allowed to cool in a ventilated furnace (if below 300 deg C). The PWHT itself and correct temp selection and distortion minimization measures are the critical issues.
The best advice with SS is to avoid PWHT. Since your internals are bolted, why not dismantle them and do PWHT of the remaining CS components?
Rgds,
Shashank Vagal
--- On Wed, 3/11/10, Kathalingam Babu <kathalingam.qaqc@ppl.com.sg> wrote:
From: Kathalingam Babu <kathalingam.qaqc@ppl.com.sg>
Subject: Re: additional detail[MW:8044] effect of PWHT Temperature at 600 DEG CELSISIUS ON SS 316L
To: materials-welding@googlegroups.com
Date: Wednesday, 3 November, 2010, 3:02 PM
Hi Karthik Yes there is more chances for the sensitation , if you SR at the sensitation temp. range after forming. Cold forming of SS316L is generally SR Iis not required, as it is having good ductility and formability. Also we need to have the Capcity of Equipment is higher than what we using for the SS304. Upto 8 mm thk, very well formed , with generally available equipments. Regards K.Babu Singapore ---- Original Message ----- Sent: Wednesday, November 03, 2010 4:17 PM Subject: Re: additional detail[MW:8043] effect of PWHT Temperature at 600 DEG CELSISIUS ON SS 316L
| hI, I agree with Mr.Babu.But as far as i know Sensitation Temp.range for SS316L is 450 to 600 degrees. My doubt is If Sensitation Temp.range for SS316L is of 600 to 850 means,In case of doing Stress reliving(some times after forming needed) around 850 degrees will it get sensitised?
Thanks & Regards,
(Karthik)
Karthikeyan.S QA/QC Manager Getabec Energy Co.,Ltd. 379,Moo6,Soi8,Nikhomphatana, Rayong-21180, Thailand. Phone: 0066 38 897035-8 (Off) Fax: 0066 38 897034 Hand Phone: 0066 892512282
--- On Wed, 11/3/10, Kathalingam Babu <kathalingam.qaqc@ppl.com.sg> wrote:
From: Kathalingam Babu <kathalingam.qaqc@ppl.com.sg>
Subject: Re: additional detail[MW:8039] effect of PWHT Temperature at 600 DEG CELSISIUS ON SS 316L
To: materials-welding@googlegroups.com
Date: Wednesday, November 3, 2010, 3:02 PM
Hi SS 316L doesn't have any Stabilizing elements. Since the lower percentage of carbon , the tendency of Cr Carbide formation is less. Sensitation temperature range for the SS316 is typically in the range of 600~850 deg. cel. If you want to do PWHT, you may do less than 575 deg. cel. and increase the soaking time accordingly. In my opinion, I'll not recommend for PWHT with internals. Regards, K.Babu Singapore ----- Original Message ----- Sent: Wednesday, November 03, 2010 3:45 PM Subject: Re: additional detail[MW:8038] effect of PWHT Temperature at 600 DEG CELSISIUS ON SS 316L
| hi, If you PWHT with Austenitic SS (SS316) internal sensitation happened at 450 to 600 degrees which will reduce the corrosion resistance of SS316(chromium becomes chromium carbide).
But in your case it is SS316L ,for this it may PWHT since 'L" grade has stabilising elements like Ti,Cb,Nb which will help to reduce the sensitation. So if you are not ready to dismantle the internal for PWHT,you may go with SS316L internal for PWHT.
Thanks & Regards,
(Karthik)
Karthikeyan.S QA/QC Manager Getabec Energy Co.,Ltd. 379,Moo6,Soi8,Nikhomphatana, Rayong-21180, Thailand. Phone: 0066 38 897035-8 (Off) Fax: 0066 38 897034 Hand Phone: 0066 892512282
--- On Wed, 11/3/10, asad azmi <azmiasadayub@gmail.com> wrote:
From: asad azmi <azmiasadayub@gmail.com>
Subject: [MW:8034] effect of PWHT Temperature at 600 DEG CELSISIUS ON SS 316L
To: materials-welding@googlegroups.com
Date: Wednesday, November 3, 2010, 1:44 PM
Dear All, Greetings. Contractor is doing PWHT of the Carbon Steel Vessel along with SS316L INTERNALS ( BEAMS, CHANNELS) Bolted with the Vessel. PWHT temperature is 600 DEG CELSIUS. Pls suggest me whether it is allowed. what will be the effect on mechanical proerties/corrosion ressiatnce proerties of SS 316L becuase of the PWHT Temperature. Thanks in advance for your valuable suggestions. Regrads -- 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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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.
-- 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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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.
-- 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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