NSC has developed a new stainless steel grade, called 317AP, which provides improved corrosion resistance to polythionic acid corrosion and naphthenic acid corrosion in refinery service. A user has requested that this grade is considered for inclusion in A240 and in other related ASTM stainless steel product specifications. A user letter and the supporting data from at least three heats steel has been provided. Additional information is available upon request. This grade is covered by a patent.
The UNS number for the new grade has been issued and is S31740. This grade has already been incorporated in ASTM specifications A182, A213, and A312. There is also an ASME code case request (under proposal RN 20-1834) for use of the UNS S31740 materials for Section VIII, Division 1 pressure vessel construction and conforming to the requirements of specifications SA-182, SA-213, SA-312, SA-240, SA-403, and SA-479
Date Initiated: 07-14-2022
Technical Contact: Elmar Upitis
Item: 001
Ballot: A01.17 (22-03)
Status: Will Reballot Item