Determination of the Crack Propagation Direction of Fractured Ductile Cast Iron Based on the Characteristic Features of the Surface

Abstract

In this article, the characteristic fractographic features of ductile cast irons with different metallic matrices were analysed. Several heat treatment cycles were carried out on samples from the same cast iron melt in order to obtain ferritic ductile iron, pearlitic ductile iron and austempered ductile iron. The specimens were broken under impact and bending tests and the fracture surfaces were analysed by means SEM observation. Two methodologies to evaluate the main crack propagation based on some characteristic features of the fracture surface were proposed. The investigation involves a systematic study of the fracture surfaces of ductile iron of different matrices. The authors propose methodologies suitable for identifying the main crack propagation direction of fracture processes of unknown origin applicable to brittle and ductile fracture cases.