Maximum Acceptable Hardness Values for Stress-Relieved Weldments in NACE MR0175/ISO 15156-2

Overview

This page addresses a common question regarding the maximum acceptable hardness values for stress-relieved weldments in NACE MR0175/ISO 15156-2. Specifically, the question asks whether Table A.1 should be applicable for stress-relieved weldments, as it does not specifically refer to it. The question also asks which hardness value, 250 HV or 275 HV, should be applicable for weld cap hardness of stress-relieved weldments.

Answer

Table A.1 gives maximum acceptable values for carbon steel, carbon-manganese steel, and low-alloy steel weldments, and it is applicable to welds whether they have been post-weld heat-treated or not. Therefore, Table A.1 is applicable for stress-relieved weldments.

Reference

This answer is based on ISO 15156 Maintenance Panel Inquiry #2011-01.

Conclusion

In conclusion, stress-relieved weldments should follow the maximum acceptable hardness values provided in Table A.1 of NACE MR0175/ISO 15156-2. The appropriate hardness value for weld cap hardness of stress-relieved weldments is either 250 HV or 275 HV, depending on the specific requirements of the project.