The effect of hydrogen concentration on fracture of pipeline steels in presence of a notch

The comparative assessment of local fracture initiation at notches in API grade pipeline steels: X52, X70 and X100 have been done for conditions of electrochemical hydrogenating. The factor of hydrogen concentration in metal was taken into account. The relationship between hydrogen concentration in metal and work for initiation of the local fracture emanating from the notch has been derived. The existence of some critical hydrogen concentration, which causes the significant loss of local fracture resistance of material, was also shown and discussed.