What are the NACE MR0175 requirements for C95800, C95400, C95500 and C63200?

Question:

We are using the following materials for manufacturing of valve components. In reference to the clause A.12.1 of NACE MR0175/ISO 15156-3:2003, no any special requirements are specified to these materials for use in SOUR environment. We wish to know what shall be the chemical, physical, hardness properties and heat treatment requirements for using these materials in SOUR service environment. Valve Components: Body – ASTM B148 UNS C95800, C95400 & C95500. Stem – ASTM B150 UNS C63200. Ball – ASTM B148 UNS C95800.

Answer:

For these materials, there are no 15156 restrictions on chemistry, hardness or heat treatment. However, note that these materials can undergo severe weight loss corrosion. They may also be susceptible hydrogen stress cracking when galvanically coupled to steel. It is up to the user to decide if qualification of these materials is necessary in the applicable sour service environment. § 8 of NACE MR0175/ISO 15156 Part 1 indicates how these materials can be qualified.

This question is in relation to NACE MR0175/ISO 15156-1 Clause 8

Reference: ISO 15156 Maintenance Panel Inquiry #2009-12

https://oilandgascorrosion.com/faqwd/mp2009-12/

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