Ductile cast iron round bars was prepared using alloys with carbon
equivalent percentage (C.E) in the range (4.50% and 4.76%). Ultrasonic
velocity and attenuation measured using pulse echo technique of frequencies 1,
2 and 4MHz .It found that ultrasonic velocity decreases with increasing size of
casting module, while attenuation coefficient increases. In addition, the nodule
count decreases with increasing the size of casting module, at the same time
nodule size increases. An empirical formula relating the ultrasonic velocity and
the mechanical properties namely ultimate strength, 0.2%-offset yield,
elongation and hardness) is suggested.