Is Nitro-Carburizing an Acceptable Surface Treatment for NACE MR0175 Compliance?

This page addresses a common question in the oil and gas industry regarding the acceptability of nitro-carburizing as a surface treatment for materials selection compliance with NACE MR0175/ISO 15156-3 Annex A.1.5.1.

Surface Treatment Requirements for NACE MR0175 Compliance

As of now, acceptable surface treatment has only been defined as nitriding below the lower critical temperature in ISO 15156. However, the industry commonly uses salt bath, liquid, or ion nitriding, including nitro-carburizing and carbonitriding, with certain process requirements.

These process requirements include a maximum case depth of 0.15 mm (0.006″”) and a process temperature below the temperature where any new transformation products are formed.

Proposed Ballot to Clarify Acceptable Surface Treatment Processes

The Maintenance Panel (MP) is proposing a ballot to clarify the description of acceptable surface treatment processes. However, this process needs to be successful before it is an approved process listed in ISO 15156.

For more information on this topic, please refer to ISO 15156 Maintenance Panel Inquiry #2013-08. Our team is also available to discuss your surface treatment requirements and NACE MR0175 compliance.