Understanding NACE HIC: Qualification and Selection of Steels for Resistance to Cracking

This appears to be a shortcode intended for use on a website. It includes two separate questions regarding hydrogen-induced cracking.

Question 1: Does Clause 7.1.1 Apply to Other Forms of Cracking?

Clause 7 of the NACE MR standard addresses the qualification and selection of C and low alloy steels for resistance to SSC, SOHIC, and SZC. Clause 7.1.1 specifically concerns SSC in low partial pressure of H₂S and does not mention the other forms of cracking. Clause 7.1.2 has three footnotes, with Note 1 referencing SSC, Note 2 referencing SOHIC and SZC, and Note 3 referencing HIC and SWC. The question asks whether these three notes should also apply to Clause 7.1.1.

Response: The applicability of Notes 1, 2, and 3 is for the entire Clause 7.1 and is not restricted to Clause 7.1.2.

Question 2: Do Steels Meeting Appendix A.2 Requirements Require Additional HIC Testing?

Clause 8 of the NACE MR standard deals with the evaluation of C and low alloy steels for resistance to HIC/SWC. The question asks if steels meeting the requirements of Appendix A.2 have already been evaluated for HIC/SWC and do not require additional HIC testing.

Response: Materials described in Annex A.2 may require additional testing to confirm resistance to SOHIC, SZC, and/or SWC. This determination should be made by the equipment user and can be influenced by factors such as the material’s production as a flat rolled carbon steel product and its chemistry.

Overall, understanding NACE HIC and the qualification and selection of steels for resistance to cracking is crucial in ensuring the safety and reliability of equipment and structures in industries such as oil and gas.