COMBINED EFFECT OF INOCULANT TYPE AND SECTION THICKNESS ON THE MICROSTRUCTURAL AND MECHANICAL PROPERTIES OF EN-GJS-600-3 GRADE DUCTILE CAST IRON

This study aims to investigate the combined effects of inoculant type (Ba- or La-containing) and section thickness (5, 15, 25, 35 and 50 mm) on the microstructural features (amount of ferrite and pearlite, the nodule count and the nodularity) and the mechanical properties (hardness, elongation, yield and tensile strength) of EN-GJS-600-3 grade DI. La-inoculated specimens exhibited lower nodule count, lower nodularity and approximately 1.1 times higher pearlite amount for all section thicknesses compared to Ba-inoculated specimens. The relatively higher pearlite content in La-inoculated specimens} resulted in improved mechanical properties (higher hardness values and approximately 1.1–1.2 times higher tensile strength). As section thickness increases, the amount of pearlite decreases (12–15%), the amount of ferrite increases (12–15%), the nodule count decreases and the nodularity increases. These results can directly be attributed to the decreasing cooling rate as section thickness increases.