Fracture characteristics of TMCP and QT steel weldments with respect to crack length

This experimental investigation focuses on an evaluation of fracture characteristics of API 2W Gr.50 (TMCP) and 580 MPa class high-strength steel (QT) weldments with respect to crack length to width ratio. Crack tip opening displacement (CTOD) values from single edge notched bending (SENB) specimen are associated with the Charpy toughness of root weld located at the middle of the specimen thickness and showed lower toughness values according to the increasing crack length to width ratio. In fractography analysis, there is no significant effect of crack tip constraint on fracture mode. The hardness values of the reheated zone in weld metal are lower than the solidified zone, and fractures are initiated at the reheated zone with low hardness values within the center third of section thickness.