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In NACE MR0175 Table A.2, are the chemistry requirements additive?

Question:

We have a question regarding the meaning of a sentence in Paragraph 4.4 in MR0175-2003. This same sentence is repeated in Paragraph 10.2.1. 62 The paragraph states: Highly alloyed austenitic stainless steels in this category are those with Ni% + 2 Mo% >30 and 2% Mo minimum. A1. Does the statement mean that there are essentially two groups in this category? Such that . . . One qualifying group consists of materials that contain N% + 2 Mo% >30 Another qualifying group consists of any austenitic stainless steel with 2% Mo minimum (such as 316, 317). A2. Or does the statement mean that there must be a minimum of 2% Mo in the Ni% + 2 Mo% >30 requirement? Since the environmental restrictions in Paragraph 4.4 are the same as in 4.2 (where most austenitics are acceptable), I assume #A1 is the correct interpretation since this would allow for inclusion of 316 and 317.

answer:

Your answer A2 is correct. The chemistry requirements are additive.

This question is in relation to NACE MR0175/ISO 15156-3 A.3.2, Table A.8 and Table A.9

Reference: ISO 15156 Maintenance Panel Inquiry #2003-15

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