Effect of hydrogen concentration on strain behaviour of pipeline steel

• We tested hydrogen charged tensile specimens.
• We measured hydrogen concentration in bulk of metal.
• We evaluated strain behaviour of steel as function of hydrogen concentration.
• We found hydrogen concentration value that changes strain behaviour of steel.

The specificity of strain behaviour of pipeline steel depending on the hydrogen concentration in bulk of metal was studied. The existence of some characteristic value of the hydrogen concentration at which the mechanism of hydrogen influence changes, namely: below this value the enhanced plasticity (decreasing of the yield stress value) takes places and above – the hydrogen embrittlement occurs, was shown. This value can be considered as an important engineering parameter for strength and fracture assessment of materials and structural components in hydrogenous environments and also at the development of technology of hydrogen treatment of materials with the aim of improvement their service properties.