SULFIDE STRESS CRACKING RESISTANCE OF API-X100 HIGH STRENGTH LOW ALLOY STEEL IN NACE TM0177 SOLUTION

摘要

Sulfide Stress Cracking (SSC) of API-X100 high strength low alloy steel was evaluated in H_2S saturated NACE solution “A” at room temperature. The corrosion rate, utilizing electrochemical polarization techniques, in the solution was 97 mpy. Proof ring testing, per NACE TM0177, generated an SSC threshold stress value of 46% of yield strength. SSC susceptibility was caused by the high corrosion rate which formed corrosion pits that acted as crack initiation sites on the metal surface and provided more hydrogen to migrate into the steel. In addition, the X100 inhomogeneous microstructure provided a high density of hydrogen traps which promoted hydrogen embrittlement.