Abstract
Fracture mechanics SENT testing and finite element simulation to establish hydrogen influenced cohesive parameters for X70 structural steel welded joints have been per-formed. Base metal and weld simulated coarse grained heat affected zone have been included in the study. The base metal did not fail at net section stresses lower than 1.29 times the yield strength and reveals low sensitivity to hydrogen embrittlement. The weld simulated coarse grained heat affected zone was prone to fracture at stresses above 64% of the yield strength, which indicates hydrogen embrittlement susceptibility. The cohesive parameters best fitting the experiments are δc=0.3 mm and σc=1500 MPa (3.1∙σy) for the base metal and δc=0.3 mm and σc=2100 MPa (2.6∙σy) for the coarse grained heat affected zone.