What does “continuous precipitates” mean in NACE MR0175?
What are Continuous Precipitates in NACE MR0175/ISO 15156-3?
Introduction
This page aims to provide guidance on the term “”continuous precipitates”” mentioned in Appendix A.7 of NACE MR0175/ISO 15156-3. The inquiry seeks clarification on what “”continuous”” means in the context of microstructure and whether there is any quantitative limit for precipitates.
Background
The laboratory has reported suspected continuous precipitates “”at some locations.”” However, the standard does not provide a definition of “”continuous precipitates.”” Therefore, the manufacturer/supplier and equipment user must agree upon an acceptance criterion or quantitative limit.
Responsibilities
It is the equipment user’s responsibility to select the appropriate CRAs and other alloys suitable for the intended service, including the selection of specific quality requirements. The team can assist in defining microstructural requirements to maintain integrity in duplex and superduplex built equipment and meet regulatory requirements such as NACE MR0175, DNV OS F101, and BS 4515-2.
Conclusion
In conclusion, while NACE MR0175/ISO 15156-3 does not provide a definition of “”continuous precipitates,”” the manufacturer/supplier and equipment user must agree upon an acceptance criterion or quantitative limit. It is important for the equipment user to select the appropriate CRAs and other alloys suitable for the intended service and to meet regulatory requirements. The team can assist in defining microstructural requirements to maintain integrity in duplex and superduplex built equipment.