Q1: For NACE MR0175 compliant products, is Carburizing an acceptable surface treatment process?
A1 Carburizing is not currently permitted in ISO 15156 except in conjunction with the permitted exclusions in Table 1 of ISO 15156-2. These exclusions are associated with specific equipment that is loaded in compression and equipment that is outside the scope of ISO 15156.
Q2: If Carburizing is not considered the same as Nitriding in paragraph A. 2.1.5, is it acceptable to have carburized surface treatment (where the surface hardness will be well over HRC 22 hardness) but the core to meet the maximum average hardness of 22 HRC?
A2: Carburizing is not permitted regardless of core hardness except as noted in Q1.
Q3: If Carburizing is acceptable surface treatment method, can the max hardness (HRC 22) and Nickel content (max 1%) of the core of carburized part be allowed to be higher than what NACE MR0175 allows?
A3: Not applicable.
This question is in relation to NACE MR0175/ISO 15156-3 Annex A.1.5.1
Reference: ISO 15156 Maintenance Panel Inquiry #2013-04
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