RE: [MW:12453] P-No. 15F, Creep-strength Enhanced Ferritic Alloys: P-number 15

Thou they allotted P number 15F for P122 material (refer below also P15A and P15D are open), it was not listed, probably because it is not being used in any of the BPV codes, but why they allotted it, could be for future? Refer Last para in introduction of the code Sec IX

 

Refer below text copied from one of the Walter sperko’s article

 

Creep-strength Enhanced Ferritic Alloys: P-number 15

The power industry has been using a creep-strength enhances ferritic alloy (CSEFA) identified as “Grade 91” for elevated temperature service for over two decades. Although Grade 91 is based on Cr-Mo steels that have been used for decades, industry has discovered that its microstructure and associated creep behavior is way more sensitive to fabrication and installation practices than predecessor Cr-Mo steels such as 2-1/4 Cr-1Mo. As the result of some failures in Grade 91 installations, special rules have been written for this material such as the postweld heat treatment requirements for P-5B, Group 2 in Section I, paragraph PW-39, and in B31.1, Table 136. While the industry has learned to deal with Grade 91’s idiosyncrasies, more CSEFAs are on the way: Grades 92, 911, 122, 23, 24 and others. It is anticipated that they will exhibit similar idiosyncrasies to Grade 91 and possibly some of their own. In order to make it easier for the construction codes to deal with these idiosyncrasies as they arise, Section IX has designated a new P-number family for CSEFAs – P-15. Assignments will be as follows:

P-15A Open

P-15B 1-1/4Cr

P-15C 2-1/4Cr (e.g. 23, 24)

P-15D Open

P-15E 9Cr (e.g. 91, 92, 911)

P-15F 12Cr (e.g. 122, VM12)

 

From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of PAUL OSIKWEMHE
Sent: Wednesday, September 14, 2011 1:16 PM
To: materials-welding@googlegroups.com
Subject: [MW:12451] P-No. 15F

 

Hello Members,

I ASME IX page 74, it is stated that for Steel and steel alloys the welding qualification is P-No. 1 through P-No. 15F

My question is : which material is P-No. 15F.

Regards

Paul Osikwemhe

Welding Engineer