Fractographic study of quasi-static tensile tested, electrochemically hydrogen charged X70 pipeline steels
Published in EUROCORR 2023, European Corrosion Congress, Proceedings, Brussels, Belgium, 2023
Abstract
Fractography evaluates surface features of failed materials to understand causes of failure and subsequently enhance material performance. This work discusses different features identified on quasistatic tensile tested, electrochemically hydrogen charged X70 pipeline steel. Ex-situ quasi-static tensile testing is performed on smooth round bars at two conditions: in air as the reference condition and after electrochemical hydrogen charging in 0.5M H2SO4 electrolyte with 1g/l thiourea at a constant current density of 0.8 mA/cm2. Scanning electron microscopy is used to characterize the fracture surfaces of the samples. A database quantifying hydrogen embrittlement indices is developed. This reveals trends in fracture behaviour with respect to microstructure and hydrogen condition applied. The macroscale features manifest as splits, delaminations, and fisheyes, whereas on the microscale dimples and quasicleavage areas are observed. The findings emphasize the correlation of microstructure to hydrogenaffected fractographic pattern recognition for the identification of possible failure mechanisms.
Recommended citation: J. Jubica et al., "Fractographic study of quasi-static tensile tested, electrochemically hydrogen charged X70 pipeline steels," in EUROCORR 2023, European Corrosion Congress, Proceedings, Brussels, Belgium, 2023.
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