NACE Stainless Steels Inquiry

The inquiry refers to NACE MR0175 / ISO 15156-3 (2015) and seeks clarification on a comment in the notes section of Table A.2 applicable to UNS S31603.

Clarification on Limits for UNS S31603

The note states that after the final solution annealing and quenching treatment, hardness and cold work incidental to machining or straightening shall not exceed the limits imposed by the appropriate product specification. However, the product specification ASTM A479 does not state a maximum hardness limit for UNS S31603, and there is no clear limit on the amount of cold work in this specification, other than for straightening purposes.

Limits on Cold Work and Hardness

The response clarifies that the cold work limit for UNS S31603 is not defined in Table A.2, only that the material shall be free of cold work intended to enhance mechanical properties. Regarding the maximum hardness limit, the response confirms that the maximum hardness with straightening cold work is 22 HRC.

Yield and Tensile Strength Limits

However, there is no defined maximum yield or tensile strength limit. While there was agreement that the maximum specified minimum yield strength needed to correspond to that of the annealed without cold work condition, there was not sufficient consensus to define what this maximum SMYS should be.

Talk to Our Corrosion Consultants and Oilfield Metallurgists

This inquiry pertains to NACE MR0175 / ISO 15156-3 Table A.2, and the ISO 15156 Maintenance Panel Inquiry reference is #2016-04. If you need technical advice on UNS S31603 and other austenitic stainless steels, talk to our corrosion consultants and oilfield metallurgists.