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[MW:12523] RE: 12516] WPS Heat treatment condition

By Materials & Welding
Hi Vijay,
 
As per QW 407.2 a change of PWHT time and temperature is a supplementary essential variable. If there is no requirement of impact properties, the PQR qualified @ 620 deg C of PWHT  may be used as the supporting PQR for performing PWHT @ 670 deg C.
 
Note:- selection of 670 deg C for PWHT would not be right for P1 material due to the fact that it would significantly soften carbon steel.If there is any hardness restriction then the PQR  and the production weld should be done at the same Time and Temperature.
 
Austenitic stainless steels do not require any PWHT ( in the temperature region of 600-700 deg C),except for solution annealing(1000-1040 deg C) to improve mechanical properties and corrosion resistance.
 
Thanks.
 
 
Pradip Goswami,P.Eng.IWE
Welding & Metallurgical Specialist & Consultant
Ontario,Canada.
Email-pgoswami@sympatico.ca,
 

From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Vijay Katkar
Sent: Saturday, September 24, 2011 11:06 AM
To: materials-welding@googlegroups.com
Subject: [MW:12516] WPS Heat treatment condition

Dear All,

Regarding heat treatment ,

I have P1 to P8 PQR with following heat treatment,

 

Loading temperature :- 350  ĢŠC 

 heating rate : 70   ĢŠC  /hr

Soaking temperature: 620  ĢŠC

Cooling rate : 70  ĢŠC/hr

Unloading temperature: 350  ĢŠC

 

our job requirement is

Loading temperature :- 350  ĢŠC

heating rate : 70  ĢŠC/hr

Soaking temperature: 670  ĢŠC

Cooling rate : 70  ĢŠC/hr

Unloading temperature: 350  ĢŠC

 

Is it possible to use above PQR for same job if yes please tell me the reference in section IX. or this not possible then why because above all temperature below lower critical temperature..

please advice your valuable experience..............

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