Rationale

Precipitation-hardened alloys used in offshore oil and gas completion equipment are prone to hydrogen embrittlement in seawater plus cathodic protection conditions. Using slow strain rate testing (SSRT), it has been determined that by restricting the titanium content to less than 1.3 wt %, the hydrogen embrittlement resistance more than doubles as measured on the NACE TM0198 Method C test. For end users to specify this restricted composition, a new UNS number has been requested by oil & gas producers so that the alloy can be dual-certified.