Effect of Welding on the Notch Sensitivity of Ship Steel

Abstract

The authors investigated the effect of welding on the low temperature brittleness of ship steel. Manual and submerged welds were used and the various Charpy impact specimens selected along a line perpendicular to welding beads were tested over a range of temperatures at which the mode of fracture changed from shear to cleavage.
The distributions of transition temperatures located off the line of the weld were determined and compared with their metallurgical structures, hardness and temperature distributions.
Generally, the fusion zone of a weld showed more extensive notch toughness than others especially at lower temperatures.
The test results showed that the brittle zone does not exactly coincide with the heat-affected zone, but was farther located from the weld than the latter.
Though the cause is not clarified, it is assumed to be the result of aging phenomena due to thermal cycles.
Further inquiry is continued on this point.