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NACE MR0175 Hardness Waiver

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wkhchin81

Materials
Dec 11, 2013
1
A.13.1:
"Unless the user can demonstrate and document the likely long-term in-service integrity of the cladding or overlay as a protective layer, the base material, after application of the cladding or overlay, shall comply with ANSI/NACE MR0175/ISO 15156-2 or this part of ANSI/NACE MR0175/ISO 15156, as applicable."

Can I interprete like this:
The BASE METAL (BM) in A.13 is not talking about the HAZ under the clad. but the major wall of the BM. Therefore the HAZ may shoot up exceeding 250 HV (e.g. 300 HV) but still acceptable by waiver, if the equipment is FULL OVERLAY EQUIPMENT.

My assumption:
1. This equipement is fully cladded with Alloy 625 and it have long-term in-service integrity.
2. The clause in NACE waiver is only for overlay whereby the HAZ is totally embedded underneath (unexposed) for FULL overlay equipment only; as there is not subseptible to HIC nor SSCC because no chemical reaction.

Remarks:
The HAZ (~2mm thick) under the 625 overlay plays no role in sour-service, if the 625 corroded to reach BM, no matter what hardness in the HAZ, the BM will corrode anyway.

 
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Not quite. It would apply to all of the base substrate, including the HAZ. However, your assumption 1, if you are happy to live by it, kills any further discussion because you are deeming that the substrate will never be exposed to any H2S containing fluid.

Steve Jones
Corrosion Management Consultant


All answers are personal opinions only and are in no way connected with any employer.
 
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