Sulfide stress cracking resistance of alloy steel rods and pumping rods: materials, methods, and design approach

This article presents the results of a study on the sulfide stress cracking (SSC) resistance of sucker rods and polished rods used in sucker rod pumping (SRP) systems. The materials investigated include 15Kh2GMF steel (in strength groups D and K as per GOST 31825-2012), 15Kh3MA steel, and 40Kh steel, all of which are widely used in the serial production of downhole pumping equipment components. An accelerated testing methodology was developed to evaluate hydrogen-induced degradation of mechanical properties in H2S environments within 48 hours. The results of this accelerated method showed strong correlation with those obtained using the standard NACE TM0177, Method A. The findings demonstrate that strength group K (15Kh2GMF-K) and 40Kh steel exhibit high resistance to SSC at stress levels up to 182 MPa, while strength group D steels (15Kh2GMF-D, 15Kh3MA) show significant plasticity loss and premature failure under the same conditions. The study also proposes engineering solutions aimed at reducing operational stress and mitigating SSC risks, including the implementation of stress relief grooves (stress concentrator eliminators) and their hermetic sealing. These results provide a sound basis for the selection of optimal materials and design strategies for the reliable operation of oilfield equipment in hydrogen sulfide–containing service environments.