Official Answer
Answer
Elgiloy is a 'super-alloy' known for its extreme resistance to Hydrogen Sulfide ($H_2S$) induced stress corrosion cracking, which is a major failure mode in 'sour' oil wells. It offers high strength and a high modulus of elasticity. For spiral retaining rings in subsea connectors, Elgiloy provides the necessary 'cling' to the groove while remaining nearly immune to the corrosive effects of seawater and sour gas. The processing involves a complex heat treatment: cold work followed by aging at $900^°F$. This results in a material with a fatigue limit far exceeding that of 17-7PH or Inconel 718 in corrosive environments.
