The above publication is great, but there's a second edition published in 2015.
You might want to consult the latest version. Free from the EPRI website.
Thx metengr, should've looked it up myself. Too bad, I recently had the 2nd ed. (100 pages or so) bound (to make a booklet). I'll have to add this publication.
No problem weldstan. Being semi-retired and working with EPRI as a consultant keeps me in touch. EPRI has really been taking the lead with ASME and the NBIC regarding PWHT and chemical composition of Grade 91 steels. More to come......
Hello All!
In relation to the discussion, regarding Post Weld Heat Treatments (PWHT) for P91 materials (Base Material P-No. 15E), it was observed that the hardness test requirements has been removed from B31.3. However, in B31.1 there was no hardness test in 2012, but newly added for cast material at 2014 and 2016.
Please refer to the following summary.
Based on the above observation, would like to know the following points.
(1) What is the technical background why the hardness test specified in ASME B31.3 (2012) has been removed from ASME B31.3 (2014) and B31.3 (2016)?
Note: Para. 331.1.7, which is referred in Para. 341.5.2 does not exist in ASME B31.3 (2014) and (2016).
(2) What is the technical background why the hardness test was not originally required in ASME B31.1 (2012) and newly added for casting material in ASME B31.1 (2014) and ASME B31.1 (2016)? Why does only casting material require hardness test, any incidents or troubles were reported?
(3) Why there are differences in the requirement of hardness test for base material P-No. 15E?
The problem has always been arguments as to the acceptable minimum hardness for Grade 91 material. This issue has been a moving target within the Code committees for some time. Hardness of Grade 91 is not a predictor of toughness nor creep strength performance and is only used as a qualitative means to measure the response of heat treatment.
Thanks metengr!
My question came up because our construction site group follows ASME B31.3 or ASME B31.1 requirements for pipe fabrication welds. However our Technology group is worried about the absence of hardness test considering experiences for failures if hardness test is not performed on fabricated pipe welds. I read the ERPI too, and will be helpful as additional reference to decide whether we perform hardness test or not.
Your company can always require hardness testing of P91 materials and welds with minimum and maximum requirements. For almost a decade my former company and a number of other EPC firms and Owners have done so.
