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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Oil and Gas Corrosion Ltd is an independent materials and corrosion consultancy for the Oil and Gas industry. Oil and Gas Corrosion Ltd is under the guidance of Ivan Gutierrez. Ivan has more than 20 years’ experience in materials and corrosion and is a member of the National Association of Corrosion Engineers (NACE), a professional member of the Institute of Corrosion (MICorr) and the Society of Petroleum Engineers (SPE). He is a recognised materials and corrosion authority recognised as a Great Britain national expert member of the British Standard Institution committee PSE/17/67/7 “Corrosion Resistant Materials” and internationally as a member of Task Group 299 on the Oversight of Maintenance Panel for NACE MR0175 / ISO 15156. “Materials for use in H2S-containing environments in oil and gas production”, IOGP 15156 Committe (ISO/TC 67/WG 7 “Corrosion Resistant Materials”. Ivan is also a member of ISO/TC 67/WG 8 Materials, corrosion control, welding and jointing, and non-destructive examination (NDE) which is responsible for standards such as ISO 21457 “Materials selection and corrosion control for oil and gas production systems”. Oil & Gas Corrosion has headquarters in the United Kingdom providing services to clients across the globe.