What are the NACE MR0175 stress relief requirements for fibre deformation greater than 5%?
Question: NACE MR0175 part 2 Annex A section A.2.1.2 refers to fibre deformation greater than 5%. Is this referring to surface strain when a residual tension stress is applied as a result of manufacturing processes? A.2.1.6 Cold deformation and thermal stress relief Carbon and low-alloy steels shall be thermally stress-relieved following any cold deforming by rolling, cold forging or other manufacturing process that results in a permanent outer fibre deformation greater than 5 %. Thermal stress relief shall be performed in accordance with an appropriate code or standard. The minimum stress relief temperature shall be 595 °C (1 100 °F). The final maximum hardness shall be 22 HRC except for pipe fittings made from ASTM A234 grade WPB or WPC, for which the final hardness shall not exceed 197 HBW.
This question is in relation to NACE MR0175/ISO 15156-2/A.2.1.2
Reference MP inquiry #2017-22
The team at Oil and Gas Corrosion Ltd can help you define the stress relief requirements to comply with NACE MR0175. Talk to our team today!