FAQ's

What are the NACE MR0175 requirements for expansion joints and flexible hoses in austenitic stainless steel?

Question:

We’re a manufacturer of expansion joints and flexible hoses and since we get more and more often inquiries regarding bellow according to MR0175 we purchased a copy of this standard some time ago. Since our bellows standard material is austenitic stainless steel, we paid particular attention to Table A.2 (attached) where there some notes about cold work and maximum hardness. Our understanding of these notes is that to meet this particular requirement we have to perform a heat treatment of the bellows after cold forming and to check the maximum hardness to be not higher than 22 HRC. Could you please tell me if our understanding is correct or what is the right method to follow to satisfy the requirements of MR0175 when the subject is cold formed bellows?

Answer:

Table A.2 is applicable to austenitic stainless steels used for ANY components. There may be other applicable tables depending on the end use of the bellows (e.g. Table A.7 for gas lift service).
If Table A.2 is the applicable table, the requirements for material conditions, hardness limit and cold forming are stated in A.2.
The MP is restricted to providing interpretations of the standard’s requirements and may not provide direction beyond this scope.

This question is in relation to NACE MR0175/ISO 15156-3 Table A.2 (cold work)

Reference: ISO 15156 Maintenance Panel Inquiry #2012-03

 

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