What happens when HIC, SOHIC or SZC fails in testing as per NACE MR0175 Part 2 Clause B.4?
Application of section B4 (Test procedures to evaluate the resistance of carbon and low-alloy steels to SOHIC and SZC). Our Interpretation: Section B4 applies to SOHIC/SZC only. Where SSC is required section B3 applies.
Section B.4 applies only to the evaluation of resistance to SOHIC and SZC as indicated, but per B.4.1 the “materials shall have been qualified with respect to SSC resistance for the design conditions prior to the SOHIC/SZC evaluation.” which is B.1 – B.3
Clause B.4.2.3 (Evaluation and acceptance criteria for FPB test specimens) third paragraph : Sections produced in these ways shall be examined for possible ladder-like HIC features and other cracks related to SOHIC or to soft zones of a weld (SZC). No ladder-like HIC features nor cracks exceeding a length of 0.5 mm in the length of 0.5mm in the through thickness direction are allowed”. Our Interpretation : the word “nor cracks’ refers to cracks associated to SOHIC and SZC only. Other than ladder-like, SOHIC and SZC including single HIC (no ladderlike) types of cracks exceeding in length the 0.5mm are accepted.
Part of the referenced text is incorrect as noted above. The missing component in your interpretation is the last part of the paragraph “No ladder-like HIC features nor cracks exceeding a length of 0,5 mm in the through thickness direction are allowed.” Thus, the paragraph does not infer what you indicate is your interpretation.
This question is in relation to NACE MR0175/ISO 15156-2/B.4.2.3
Reference MP inquiry #2017-20
The team at Oil and Gas Corrosion Ltd can help you review the HIC/SOHIC test results and make sure your material is fit for sour service use. Talk to our team today!