If a weld is qualified to NACE MR0175, is NACE TM0177 required?
About welds, in accordance with NACE MR0175/ISO 15156, Part 2, Item 22.214.171.124, “hardness acceptance criteria for welds,” “weld hardness acceptance criteria for steels selected using option 1 (see 7.1) shall be as specified in A.2.1.4. Alternative weld hardness acceptance criteria may be established from successful SSC testing of welded samples. SSC testing shall be in accordance with Annex B.” So, in our understanding, if our welding procedure qualifications (WPSs) are qualified in accordance with NACE MR0175/ISO 15156, Part 2, Item A.2.1.4, it is not necessary to test them according to NACE TM0177. We would like you to confirm whether our interpretation below is correct and if not give us the correct interpretation.
Your interpretation is correct.
NACE MR0175/ISO 15156 and NACE TM0177–WELDS
On the other hand, if we make the test in accordance with NACE TM0177 in our WPSs that are previously qualified to conform to NACE MR0175/ISO 15156, what kind of results will we have? Will we have necessary or redundant results?
A manufacturer may choose to qualify a welding procedure specification in accordance with ANNEX B. Testing welds acceptable in accordance with A.2.1.4 is an optional activity chosen by the manufacturer to confirm resistance to cracking. This is not necessarily a redundant result depending on the anticipated service conditions and the selected test environment, the results could be used
-to confirm that the hardness control specified in A.2.1.4 is adequate to prevent sulfide stress cracking
-or to define alternative weld hardness control requirements that will not lead to sulfide stress cracking when the requirements of A.2.1.4 are not met.
Reference: ISO 15156 Maintenance Panel Inquiry #2005-08 Q1, Q2 and Q3
This question is in relation to NACE MR0175/ISO 15156-1 Clause 7
At Oil & Gas Corrosion we can resolve your queries in welding procedures and qualifications to meet NACE MR0175.