Clarification on Clause NACE MR0175/ISO 15156-2 B.4.2.3

This inquiry pertains to the clause NACE MR0175/ISO 15156-2 B.4.2.3 that outlines evaluation and acceptance criteria for FPB test specimens. Two questions are presented for clarification:

1. Reporting Blister Depth

The clause states that blisters less than 1mm below the surface on the tensile side or any depth on the compression side may be disregarded for SOHIC/SZC assessment but must be reported. The inquiry asks if blisters greater than 1mm below the surface are not allowed, or if they need to be reported as “”blisters more than 1mm below the surface.””

The response: clarifies that blisters greater than 1mm below the surface are not acceptable.

2. Reporting Cracks and Blisters

The clause also states that ladder-like HIC features and cracks longer than 0.5mm in the through-thickness direction are not allowed. The inquiry questions whether cracks in an area affected by a blister should be disregarded and if both blister and crack need to be reported.

The response: indicates that if both cracks and blisters are present as defined in Clause B.4.2.3, they both need to be reported.

This inquiry pertains to NACE MR0175/ISO 15156-2 B.4.2.3 and refers to ISO 15156 Maintenance Panel Inquiry #2016-12. A new standard for Four Point Bend testing for sour service, NACE TM0316 2016, has been published and is available for review. Contact us for more information on Four Point Bend testing requirements.

For more information on Four Point Bend testing requirements, please contact us.