NACE MR0175 requirements for 718 springs
We are having some discussions with a user who tells us that Table A.32 ‘Environmental and materials limits for precipitation-hardened nickel-based alloys used for any equipment or component’ can be referred to for spring materials, and therefore Inconel N07718 can be used for spring as long as it is solution-annealed and aged to a maximum hardness of 40 HRC. However the Table A.36 ‘Environmental and materials limits for precipitation-hardened nickel-based alloys used as springs’ does not list N07718. How should I interpret these tables for nickel-based alloys springs? Can I follow table A.32?
Materials listed in 15156-3 Table A.32 are acceptable for “any equipment or component” including springs. Other materials from other “any equipment or components” tables may also be acceptable for springs if used within the metallurgical and environment limits specified in the applicable tables.
This question is in relation to NACE MR0175/ISO 15156-3 A.9.2, Table A.32
Reference: ISO 15156 Maintenance Panel Inquiry #2013-03