Ultrasonic and mechanical studies of some properties of ductile cast iron

Ultrasonic and mechanical studies of some properties of ductile cast iron
Ahlam M. Abdel-Fattah, Ultrasonic Dept., NDT Lab., National Institute for Standards,. Giza, Cairo, Egypt;
M. El-Gazery Ultrasonic Dept., NDT Lab., National Institute for Standards, Mza, Cairo, Egypt;
H. Abdel-Kader, Faculty of Eng. and Tech., Helwan University, Giza, Cairo,Egypt

Review by NDTnet
Cylinderical specimens of ductile cast iron with two matrix (pearlit-ferrite and ferrite) and different diameter were investigated before and after tensile test. The investigation used pulse echo technique. Ultrasonic velocity and attenuation measurements were taken at a frequency 4 MHz (long, small diameter and uniform near field). The results showed a decrease of ultrasonic velocity and increase of ultrasonic attenuation of the same test specimens after failure by tensile test. Microstructure affect substaintially the mechanical properties of ductile cast iron, Ultrasonic pulse echo technique have been used for several years for flaw detection of shrinkage, gas defects, and cracks. Ultrasonic velocity can provide information about strength, Elastic modulus, and microstructure of irons. In ductile cast iron the ultrasonic waves can passe more reasily because of a greater matrix continunity and more regular graphite shape. Excellent relationships have been found between ultrasonic velocity, nodule count, strength and hardness.