Interrupted accelerated cooling (IAC) in comparison with normal air cooling after rolling is introduced into the production of the API-5CT-C110 casing steel. Sulfide stress cracking (SSC) resistance is improved by IAC processing without compromising strength. Multiple characterizations combined with hydrogen permeation tests are performed to reveal the mechanism of SSC behavior with respect to hydrogen interactions with metallurgical defects (grain boundaries, dislocations and precipitates). The results indicate a low dislocation density and increased amount of irreversible traps are responsible for the superior SSC resistance of the IAC specimen. A model of local hydrogen concentration is proposed to illustrate SSC susceptibility. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.