In NACE MR0175, what are the hardness requirements for SS254Mo (UNS S31254)?


We have a query about Hardness of SS-254SMO (Grade) S31254 (UNS Number). We used ASTM A182 Gr F44 in Valve Components (Seat ring and Bonnet Bush).
As per Nace MR 0 175 Hardness doesn’t specify for the UNS S31254 material. But Nace MR 0 103 Stated that 35 HRC (Max).
Please clarify the below.
1. Nace MR 0 175 Hardness not specified for SS-254SMO (Grade) S31254 (UNS Number) – Correct or Not?
2. Referring Nace MR 0 103 specified for SS-254SMO (Grade) S31254 (UNS Number) – 35 HRC (Max) – Please confirm.
The applicable tables for the subject alloy are A.8 thru A.11. As shown in Table A.8, there are no hardness requirements for material in solution-annealed condition used for any equipment or components; however, the cast version of UNS S31254, which is UNS J93254 (solution heat-treated and water-quenched condition), has a maximum hardness of 100 HRB. Table A.9 for downhole tubular components and packers and other subsurface equipment indicates that the material shall be in the solution-annealed and cold-worked condition with a maximum hardness of 35 HRC.

Reference MP Inquiry 2017-18 (NACE MR0175 Part 3 A.3.2 Table A.8)


Talk to an expert

Get in touch with us