Strength and ductility of fillet welds with transverse root notch

Abstract

Results from twenty-four cruciform weld experiments and complementary finite element simulations are presented to study the effect of the weld root notch on strength and ductility of fillet welds. All specimens are loaded in tension such that the weld root notch is perpendicular to the direction of loading, producing a crack-like effect. Two weld classifications (toughness rated E70T7-K2 and non-toughness rated E70T7; both Grade 480 MPa), two weld sizes (12 mm and 8 mm) and two root notch lengths (32 mm and 64 mm) are tested. Results of supporting ancillary tests, including all-weld tension coupons, Charpy V Notch impact tests and spectrochemical analysis are presented. The cruciform tests indicate that the strength of fillet welds is not affected significantly by the presence of the root notch. The E70T7-K2 welds show approximately twice the ductility of the E70T7 welds, whereas the E70T7 welds show a slightly reduced ductility as compared to previous published data for lap-welded joints. However, for the range of parameters tested, the ductility for all the welds is relatively insensitive to root notch length. Complementary fracture mechanics based finite element simulations are conducted to examine and generalize experimental findings. The simulations indicate that larger notch lengths do not further reduce the strength and ductility of the welds.