Material selection is very critical and crucial for sour systems. Following standards and regulations alone is not sufficient to prevent failures that may occur if account is not taken of other aspects of corrosion. This paper shows how UNS N07750, that NACE MR0175 lists as resistant to cracking in sour service, failed due to sensitization, a deficiency that MR0175 does not prevent.
Keywords: hydrogen embrittlement, sour gas, UNS N07750, sensitization, nickel base alloy, material selection.