Constraint effects on crack tip stress fields for cracks located at the fusion line of weldments

The case of a deeply notched (a/W = 0.3) surface crack positioned at the fu sion line of a weldment is considered. The tensile properties of the base m aterial and the heat affected zone (HAZ) are kept constant, while the weld metal properties are changed. First the weld metal yield strength overmatch es both the base material and the HAZ, and in the second case there is yiel d strength evenmatch between the HAZ and weld metal and overmatch with resp ect to the base material. The effect of these strength mismatch conditions has been examined for two fusion line geometries: straight and slant fusion line. The effect of the crack tip constraint has been characterized with t he J-Q-M approach where both geometrical and material mismatch effects can be considered with respect to the critical conditions for cleavage fracture initiation. (C) 1999 Elsevier Science B.V. All rights reserved.