Ablation Casting of Thin-Wall Ductile Iron

An unalloyed thin-wall ductile cast iron with the chemical composition of C = 3%, Si = 4.15%, Mn = 0.36%, Mg = 0.04%, and carbon equivalent of 4.39% was cast by both conventional and ablation casting in sections of nominal thickness 1, 2, 4, 8 mm. The effect of various commercial inoculants (based on Zr, Sr, and Ba) on microstructure and mechanical properties of the samples was investigated. In the ablation casting, the mold is eroded away by water, and the water becomes responsible for the heat transfer from the casting. In our work, ablative cooling could not be applied quickly enough to have any influence on the microstructure of the 1 mm thick cast section. In the 2-mm-thick specimen, ablation increased the nodule count from 497 to 1484 and graphite nodularity from 76 to 93%. In the 8 mm section, the tensile yield strength increased from 539 to 624 MPa and elongation was increased from 4.9 to 10.2%.