What Are the Criteria for Hic Retesting in NACE MR0175?

NACE MR0175 Part 2 Clause B.2.2 offers clear guidance regarding SSC/HIC/SOHIC/SZC retesting. If a single specimen fails to meet the acceptance criteria, the root cause should be investigated. If the source material aligns with the manufacturing specification, two additional specimens may be tested from the same source as the failed specimen. If both specimens satisfy the acceptance criteria, the test batch will be deemed qualified. Subsequent retesting will require approval from the purchaser.

Question:

An interpretation of clause B.2.2.2 e) in annex B of MR0175/ ISO 15156-2 is requested. The third paragraph states that re-testing is allowed as follows: If a single specimen does not satisfy the acceptance criteria, two additional specimens may be tested. If, after conducting HIC testing to TM0284 on a 0.5″” plate, two out of three specimens fail to satisfy the acceptance criteria, is it allowable to test four additional specimens in order to qualify the batch? As a new source may be required based on this interpretation, a prompt reply would be appreciated.

Answer:

ISO 15156-2:2015 – Annex B, Clause B.2.2 provides for retesting if NACE MR0175 Part 2 Clause B.2.2 offers clear guidance regarding SSC/HIC/SOHIC/SZC retesting. The criteria for HIC retesting in NACE MR0175 are clearly defined in this clause. If a single specimen fails to meet the acceptance criteria, the root cause should be investigated. If the source material aligns with the manufacturing specification, two additional specimens may be tested from the same source as the failed specimen. If both specimens satisfy the acceptance criteria, the test batch will be deemed qualified. Subsequent retesting will require approval from the purchaser.