A335 has heat treatment requirements for Grade P91 that have resulted in inquiries indicating that clarification would be beneficial. This proposal makes clear that normalizing and tempering or quenching and tempering are both permitted, regardless of size or thickness and that there is no technical reason to require permission of the purchaser. This change has been made recently in A182 for F91. This revision also clarifies that where more than one heat treatment is listed for a Grade in Table 2, only one of these heat treatments need be performed.
Keywordsalloy steel pipe; high temperature service; seamless steel pipe; steel pipe; temperature service applications;;
Ballot Item Approved as A335/A335M-2018 and Pending Publication