PWHT- ASME B31.3 2014 2

[ispengg]

Greetings,

I was going through the 2014 version of ASME B31.3. Major changes have been made, especially in Para.330- Preheat & 331-Heat treatment. I want to get clarified on the following:

1. What is the rationale behind setting 600 deg F/hour [divided by 1.5 times the thickness in inches] as heating and cooling rate. Is it from distortion point of view?. For example, UCS-56, ASME Sec VII Div 1 has set 400 deg F/hour divided by thickness in inches.[I accept, that is for pressure vessel even then]

2. How the extended holding time is calculated for Alternate post weld heat treatment? I just checked the time temperature combination using LMP parameter [since it is based on Jaffe-hollomon tempering parameter].If it is based on time temperature parameter, then it should yield same parameter value for all the combination, but it is not [see the attachment]. Am I missing something??

 

[metengr]

I believe the attachment below will provide a better understanding of the consolidation effort being performed by ASME B&PV Code committees and Piping committees;

http://awo.aws.org/wp-content/uploa...posedNewASMEB31PStandardbyRichardCampbell.pdf

 

[ispengg]

Metengr,

Thank you...