Stabilised grades are treated in that range,
Reference can be taken from NACE –RP-0170-2004-Protection of Austenitic Stainless Steels and other Austenitic Alloys from Polythionic SCC During Shutdown of Refinery Equipment.
· Such heat treatments are performed at 843ºC to 900ºC (1550ºF to 1650ºF) for 2 to 4 hrs for forming Ti or Nb carbides.
· The stabilizing heat treatment should be performed after the material has been solution annealed.
Yes, it is required to repeat PWHT after weld repair. To know the effect of second PWHT you may perform a simulated test coupon
From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Muni Andy
Sent: Thursday, January 06, 2011 7:03 PM
To: materials-welding@googlegroups.com
Subject: Re: [MW:9118] PWHT Of 347H
Dear Mr.KB,
It is a austenitic stainless steel.
The correct temperature is 1080 Deg C.It is to be Water Quenched.
Regards,
C.Muniyandi
On Thu, Jan 6, 2011 at 3:19 PM, Bazrafshan,kazem <KBazrafshan@bpc.co.ir> wrote:
Dear Sir:
Thanks for support.
I am worry about mechanical and chemical properties of material after repeating Heat treatment. You know after new PWHT the material will affected for 6 Hours. also May be we will found new cracks after PWHT, what can we do in order to prevent new cracks.
Regards
K.Bazrafshan
From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Karthik
Sent: Thursday, January 06, 2011 12:24 PM
Subject: Re: [MW:9115] PWHT Of 347H
| Hi, Thanks & Regards, (Karthik)
Dear All: An urgent question: Base on Project tech Documents we have to do PWHT( in 870°C for 3Hours,Air Cooled) for welding of 2 parts as A312-347H(12.7mm) to A182-347H(6mm,) together((A182 is as a branch to A312). After performing PWHT we found some cracks(dept of crack are from 3 to 8 mm) Just in weld seam. Joint Information: Welding process: GTAM + SMAW. Design Tem: 780°C and Design Pressure is 5.3Barg in convection coils. Welding consumables are :E347H Esab, Wire ER347 esab. Shall we repeat PWHT after repairing or not? If reply is Yes, how much time shall be Holding time ? Please let me know your STD reference As well. Thanks Bazrafshan |
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