On the spatial variation of the mechanical properties of ductile iron castings with non-uniform geometry

This study investigates the influence of non-uniform geometry on the local cooling conditions, microstructural evolution and static mechanical properties of ductile iron EN-GJS-500-7 castings, using the triangular section of a standardized Type III Y-block casting as a representative geometry. A combined experimental and simulation-based approach is employed to correlate mechanical performance with key microstructural parameters, including pearlite and ferrite fractions, nodule count, nodularity, and shrinkage porosity. Although the geometrically thinnest section exhibits the highest pearlite fraction, it displays the lowest tensile strength due to prolonged local solidification conditions that promote coarser graphite morphology, reduced nodularity, and increased shrinkage porosity. The results demonstrate that local mechanical performance in complex castings cannot be inferred from section thickness or pearlite fraction alone but must be interpreted in the context of the overall thermal history and resulting microstructural evolution. Thus, the study highlights the risks of extrapolating mechanical trends from uniform-thickness castings to non-uniform geometries and provides insights for improved design and performance prediction in ductile iron components