API 5CT/ISO 11960 Grades in
NACE MR0175/ISO 15156 Pt. 2
John W Martin
INHERENTLY RELIABLE FACILITIES

Listing of API 5CT/ISO 11960 Grades
• Group 1
− H40, J55, K55, N80 Type 1, N80Q, R95
• Group 2
− M65, L80 Type 1, C90 Type 1, T95 Type 1, C110*
• Group 3
− P110
• Group 4
− Q125 Type 1
*Not presently covered in NACE MR0175/ISO 15156 Part 2
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Clause A.2.2.3 NACE MR0175/ISO 15156 Pt. 2
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Table A.3 NACE MR0175/ISO 15156 Pt. 2
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Table A.3 NACE MR0175/ISO 15156 Pt. 2
R95
N80Q N80 (Q or type 1) Q125 type 1
Delete year reference (2001)
Note b can be deleted
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Future Work/Ballot
How to deal with API 5CT/ISO 11960 Grade C110?
− This is the closest available. Is it adequate? Can the Grade be listed?
Properties of API 5CT/ISO 11960 Grade C110:-
− Chemistry – C 0.35 max.; Cr 0.4 to 1.5; Mo 0.25 to 1.00
(e.g. UNS G41350 C 0.33 to 0.38; Cr 0.80 to 1.10; Mo 0.15 to 0.25)
− Heat Treatment – Quenched and Tempered (649 ° C; 1200 ° F min.)
− Yield Strength (range) – 758 to 828 MPa (110 to 120ksi)
− Maximum Hardness – 30 HRC
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