NACE MR0175 – Carburizing as Surface Treatment

Q1: For NACE MR0175 compliant products, is carburizing an acceptable surface treatment process?

A1: Currently, carburizing is not permitted in ISO 15156, except in specific cases mentioned in Table 1 of ISO 15156-2. These exceptions are related to certain equipment subjected to compressive loading or equipment that falls outside the scope of ISO 15156.

Q2: If carburizing is considered different from nitriding, as stated in paragraph A.2.1.5, can a carburized surface treatment be acceptable? For instance, can the surface hardness exceed HRC 22 while maintaining a core hardness within the maximum average hardness of 22 HRC?

A2: Carburizing, regardless of core hardness, is not allowed except as mentioned in the previous answer (Q1).

Q3: If carburizing is an acceptable surface treatment method, can the maximum hardness (HRC 22) and nickel content (up to 1%) of the carburized part’s core exceed the limits specified in NACE MR0175?

A3: This question is not applicable since carburizing is not an accepted surface treatment method in NACE MR0175.

Please note that the responses provided are based on the information available and the guidelines outlined in NACE MR0175/ISO 15156. It is important to refer to the latest version of the standard and consult with relevant authorities for specific and up-to-date information regarding carburizing as a surface treatment in compliance with NACE MR0175.