Funct. Mater. 2025; 32 (3): 423-428.
Resistance of manganese steel to hydrogen sulfide embrittlement
1 International Academy of Applied Sciences in Łomża , 19 Studencka Str., 18-400 Łomża , Republic of Poland
2 Kharkiv National Automobile and Highway University, 25 Yaroslava Mudrogo Str., 61002 Kharkiv , Ukraine
3 Prydniprovska State Academy of Civil Engineering and Architecture, 24a Architect Oleh Petrov Str., 49000 Dnipro, Ukraine
This study investigates the effect of hydrogen sulfide (H2S) environments on the mechanical properties and microstructural evolution of 30G2 manganese steel used for coupling pipes. Tensile tests were performed on specimens in the initial state and after 720 hours of exposure to an H2S-saturated medium following the MSKR 01-85 procedure. The as-received steel demonstrated superior strength (σB = 842 MPa, σT = 736 MPa) and ductility (δ5 = 19.6%, ψ = 65.6%) compared to standard 30G2 values, indicating thermostrengthening . After prolonged H2S exposure, strength parameters decreased only slightly (by 2–3%), while ductility dropped more noticeably (by 10–13%), but remained acceptable for pipeline applications. Fractographic analysis revealed a transition from a ductile–brittle to a more brittle fracture behavior with the presence of hydrogen-induced cracks. The findings confirm the suitability of modified 30G2 steel for oil and gas pipelines operating in aggressive H2S environments, and suggest that further optimization of alloying and heat treatment could enhance resistance to hydrogen embrittlement.