The aim of this experimental work was to design a modified test with which it will be possible to determine the fluidity of ductile cast iron. First, we planned the conceptual verification of the ...designed experiment, which was done by numerical simulations of the casting processes, followed by rapid mould fabrication using 3D printing. A measurement cell was placed in the mould cavity of the experimental chamber for further investigation of the cooling and solidification during casting. From the matrix of data obtained with the experiment, we defined the fluidity of the ductile iron EN-GJS-500-7. Also, we analysed the mechanical properties of the studied alloy, the microstructure, the chemical composition, and the results of the thermal analysis. In accordance with the expectations and theory from the literature, the fluidity in the experimental sample cast at a higher temperature was better than that cast at a lower temperature. Because of the faster cooling rate at the end of the channel of the experimental casting, the microstructure is fine, moreover, we obtain white solidification, ledeburite in the microstructure of the samples etched with Nital. At lower cooling rates, fewer graphite nodules appear in the microstructure, which are larger, and the portion of ferrite is greater.
Melt modification is a method commonly used when enhancing mechanical and microstructural properties of various alloys. The addition of heterogeneous nucleation sites generally refines the given ...microstructure and enhances the toughness of the material. Ferroalloys based on high-melting elements require a longer incubation time in the melt which makes them liable candidates for modification agents. A research on the effect of melt modification was conducted on an indefinite chill cast iron alloy commonly used for working layers in rolls. The goal of the research was to determine the effect of ferrovanadium and ferrotungsten melt treatment with the use of thermal analysis along with thermodynamic modelling using the CALPHAD approach. The results show a decrease in the measured liquidus temperature of the modified alloy along with a possible second eutectic reaction hidden inside the main graphite/cementite eutectic reaction. Scanning electron microscopy revealed small and evenly distributed MC type carbides rich in
V
with
W
and other carbide-forming elements. The results presented in this work enable a better understanding of the impact melt modification has on the development of microstructure and subsequently the improvement in mechanical properties of the alloy.