SOLIDIFICATION CONDITIONS OF GRAY AND WHITE CAST IRON. PART II - EXPERIMENTAL VERIFICATION

Abstract

In this work, an experimental verification of the theoretical principles for the transition from gray to mottled and white cast iron solidiflcation is presented. Experimental tests have been implemented using plate and wedge shaped castings of various sizes. The experiments inctuded inoculated and non-inoculated cast irons of different chemical compositions and time after the inoculation treatment. In addition, thermal analysis tests were employed to determine the degree of undercooling of graphite eutectic deltaTm. This included microstructural evaluations in order to establish the density of eutectic grain (cells). This procedure enabled the calculation of the theoretical grain density (cell count) N, the wedge value w, as well as the chilling tendency CT of cast iron. It was found that the predietions of the theoretical analysis are in good agreement with the experimental outcome for the chill exhibited in wedge and plate shaped castings.