Tailoring the mechanical property and sulfide stress corrosion cracking resistance of rare earth doped casing steel by tempering treatment

Rare earth (RE) doped casing steel subjected to a modified tempering treatment exhibited enhancement of strength and sulfide stress cracking (SSC) resistance. A double-cantilever beam method (in term of critical stress intensity factor: K _ISSC), was used to evaluate SSC susceptibility, where specimens were stressed and immersed in acidic solution containing H ₂S to simulate the real operating condition. Microstructural evolution and multiscale fractographic analyses were performed, the RE doped sample tempered at 710 °C achieved a higher yield strength of 794 MPa and a mean K _ISSC of 35.9 MPa ∙m ^0.5, attributed to establishment of uniform tempered martensite structure with low dislocation density.