FAQ's

What are the NACE MR0175 limits for UNS J93254 (A351 CK3MCuN)?

Permissibility of Using Forging Grade Equivalent of J 93254 in NACE MR0175

This page features an inquiry regarding the permissibility of using the forging grade equivalent of J 93254 in NACE MR0175. The question refers to Table A-8 of NACE MR0175/ISO-15156-2003, which specifies the environmental and material limits for highly alloyed austenitic steels used in equipment and components.

Acceptability of J 93254 in Production Environments

The material J 93254 (ASTM A 351 CK3MCuN) listed in Table A-8 is acceptable for use in any combinations of temperature, pH₂S, chloride concentration, and in situ pH occurring in production environments. The inquiry seeks clarification on whether the forging grade equivalent of J 93254, UNS 31254, is also qualified for use under these conditions.

Revised Limits for UNS J93254

The answer provided states that Table A.8 is undergoing revision to limit the application of UNS J93254. The revised document has been accepted by the ISO 15156 Maintenance Panel, NACE TG 299 (ISO 15156 Oversight Committee), and ISO TC67 WG7, and will be published within the coming year.

Reference and Update

This question pertains to NACE MR0175/ISO 15156-3 A.3.2, Table A.8, and the reference cited is ISO 15156 Maintenance Panel Inquiry #2006-12. An update is provided, indicating that the latest revision of NACE MR0175/ISO 15156 includes an update on the UNS J93254 limits.

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