Role of the V-Notch Location in the Impact Toughness of 9 Pct Cr-CrMoV Dissimilar Welded Joints

The location of the V-notch in a weld metal (WM) can have a significant influence on the impact toughness of a 9 weight percent (9 pct) Cr-CrMoV dissimilar welded joint. The specimens with the V-notch at position I, which was parallel to the filling direction, presented small fluctuations in the impact toughness, while relatively larger fluctuations occurred in the specimens with the V-notches parallel to the welding direction (position II). Several equiaxed grain zones favorable to hindering the crack propagation could ensure less fluctuation in the impact toughness. In contrast, the columnar and equiaxed grain zones could be clearly distinguished in the specimens with the V-notches at position II. The differences in the crack propagation paths and tip locations of the V-notches are regarded as the main factors causing the fluctuations in the impact toughness.