TWI Industrial Member Report Summary 294/1986
By J Kudoh and H G Pisarski
This report describes an investigation of the effect of locally embrittled regions, in 25mm thick multipass submerged-arc welds made in a C-Mn steel, on Charpy V and CTOD fracture toughness. Local embrittlement was effected by modifying the aluminium content of the weld beads through aluminium powder additions to the flux. The results for Charpy V specimens demonstrate that if the region of embrittlement occupies more than 30% of the notch tip then toughness is controlled by the lowest toughness region. However, for CTOD specimens, notched through the plate thickness, the presence of only 12% embrittled weld metal in the central pan of the notch significantly reduced fracture toughness. Nevertheless, the toughness measured in these specimens was not as low as that obtained in surface notched specimens in which the crack tip was totally located in the embrittled weld bead.