Study of Hydrogen Embrittlement of steels for the Oil & Gas sector through Electrochemical Methods

The objective of this study is to investigate hydrogen embrittlement in steels used in the Oil & Gas sector, aiming to ensure safe hydrogen transport and storage in existing infrastructures. The materials investigated are T95 and P110 steel grades, according to API 5CT specifications for casing and tubing, and API 5L X60 pipeline steel produced via Thermo-Mechanical Controlled Processing (TMCP) These low- and micro-alloyed steels exhibit a tempered martensitic microstructure. A comprehensive characterization was performed, including microstructural analysis, hardness measurements, tensile properties, and fracture mechanics evaluation. Hydrogen diffusion was measured using the Devanathan–Stachurski method. The experimental diffusion coefficient was combined with Finite Element Modelling to define optimal pre-charging conditions, ensuring uniform hydrogen distribution prior to mechanical testing. J-integral tests were conducted on hydrogen pre-charged samples to assess the effect of hydrogen on fracture toughness. Variations in toughness were correlated with microstructural features and fracture morphologies observed in charged specimens.