RE: [MW:9956] Change in sequence of PWHT cycle

Dear JJ,

 

Can you please state purpose of these two different PWHT cycles?

 

It seems that first cycle (660 - 640 °C for 2 hrs) is for intermediate stress relief (ISR) after welding and second cycle (687 °C for 8 hrs) is for final PWHT. 

If these two cycles are ISR & final PWHT, ISR shall be done immediately after welding.

 

Regarding effect of PWHT, any heating above 480 °C is considered to have effect on mechanical properties of metal (reduction in yield strength and tensile strength).

Irrespective of the sequence of PWHT / heating cycles, total effect on mechanical properties will be same. Total effect on tensile properties is calculated by finding the "Holloman Parameter (HP)" for each individual cycle and then adding together. For more information, see below links from Dillinger web site.

 

http://www.dillinger.de/hollomon/help.shtml.en 

 

http://www.dillinger.de/hollomon/examples_js.shtml.en

 

Regards,

 

 

Santosh Latake

 

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From: materials-welding@googlegroups.com [materials-welding@googlegroups.com] on behalf of joshi jaydeep [jaydeep.p.joshi@gmail.com]
Sent: Saturday, February 19, 2011 11:41 AM
To: materials-welding@googlegroups.com
Subject: [MW:9941] Change in sequence of PWHT cycle

Dear all,

 

 

I have and PWHT cycle of 600-640 Deg C for 2 Hrs followed by 687 Deg C for 8 Hrs.

 

will it make any difference in any of the properties of WM &/or BM if I change the sequence of PWHT cycle i.e.first cycle of PWHT for 687 for 8Hrs followed by 600-640 for 2 Hrs?

 

Material: LAS

 

regards,

 

JJ

 

 

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