Fig. 1 Schematic diagram of processing direction a and geometry size b of compact tensile specimen

Fig. 2 a Macro profile of weld joint with A flux, b macro profile of weld joint with B flux, c equiaxed crystals in the center of weld manufactured by A flux, d equiaxed crystals in the center of weld manufactured by B flux, e, f micromorphology of equiaxed crystals in the center of weld manufactured by A flux, g, h micromorphology of equiaxed crystals in the center of weld manufactured by B flux

Fig. 3 Crack propagation curve (J-∆a) of weld metal with flux A and flux B: aJ-∆a resistance curves of A flux, bJ-∆a resistance curves of B flux

Fig. 4 Fracture morphologies of weld metal: a overall fracture surface of weld metal with A flux, b tear dimples marked as B in a, c equiaxed dimples marked as C in a, d detailed feature of equiaxed dimples marked as D in c, e overall fracture surface of weld metal with B flux, f tear dimples marked as B in e, g equiaxed dimples marked as C in e, h detailed feature of equiaxed dimples marked as D in g

Fig. 5 a Inclusions morphology of weld metal with A flux, b inclusions morphology of weld metal with B flux, c compositions of inclusion in weld metal with A flux, d compositions of inclusion in weld metal with B flux, e inclusion diameter statistics for weld manufactured by A flux, f inclusion diameter statistics for weld manufactured by B flux

Fig. 6 Crack propagation path of different fluxes: a notch morphology of weld with A flux, b notch morphology of weld with B flux, c crack propagation path of weld with A flux, d crack propagation path of weld with B flux, e crack profile

Fig. 7 Microscopic morphologies of crack propagation path: a crack propagation path for WM with A flux, b detailed feature of the B area in a, c crack deflection for WM with A flux, d detailed feature of the D area in c, e crack propagation path for WM with B flux, f detailed feature of the F area in e, g, h blocky island for WM with B flux

Fig. 8 EBSD analysis results of crack propagation path for WM by A flux: a band contrast and grain boundary (green 5° < $\theta$ < 15°, black $\theta \ge 15^\circ$), b inverse pole figure, c strain distribution, for WM by B flux: d band contrast and grain boundary (green 5° < $\theta$ < 15°, black $\theta \ge 15^\circ$), e inverse pole figure, f strain distribution

Fig. 9 Distribution of grain orientation along crack propagation path: a A flux and b B flux