Recently, standardized solution strengthened ferritic ductile irons have met the interest of the industrial world since their improved mechanical properties and workability compared to standard ferritic-pearlitic ductile irons. For this reason, mechanical and fatigue properties of heavy section solution strengthened ferritic ductile irons castings are examined. Mechanical tests are carried out on specimens taken from the center of castings with long solidification times. Metallographic analyses are performed by using optical microscopy. Fracture surfaces of fatigue specimens are investigated in order to evaluate crack initiation and propagation zones. Finally, fatigue curves of the analyzed alloy are compared with those obtained from pearlitic ductile iron with the same casting geometry.
In this paper, the influence of the in-mould inoculant composition on microstructure and fatigue behaviour of heavy section ductile iron (EN GJS 700-2) castings has been investigated.\ud
Axial fatigue tests under nominal load ratio R=0 have been performed on specimens taken from the core of large casting components. Metallographic analyses have been carried out by means of optical microscopy and important microstructural parameters that affect the mechanical properties of the alloy, such as nodule count, nodularity and graphite shape, were measured. Furthermore, Scanning Electron Microscopy was used to investigate the fracture surfaces of the samples in order to identify crack initiation and propagation zones.\ud
Cracks initiation sites have been found to be microshrinkages close to specimens’ surface in most cases. It was found that in-mould inoculant composition strongly influences the alloy microstructure, such as nodule count and shrinkage porosities size, as well as the fatigue resistance of heavy section ductile iron castings
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.