Abstract
Via the use of iron-carbon phase diagram and the theory of graphitization of carbon in cast irons, this study investigates an innovative method for continuously, effectively and efficiently, as well as environment-friendly producing graphite in a catalytic cast iron bath. It is concluded that the transformation from amorphous carbon to graphite via the method is available, and the degree of graphitization (DOG) described in this study reaches a high value of more than 93% like that of Acheson’s. Furthermore, the DOG is process-controlled and is independent of carbon source in the hypereutectic catalytic cast iron melt. The observance of graphite flotation in liquid catalytic cast iron bath manifests the production of graphite is achievable by the fluidized bed method. The first part of this study describes the inductive melting (IM) of alloys of iron, carbon, and silicon at 1600oC for full melting; holding at temperatures higher than the eutectic temperature of 1500oC for 4 h for graphitization of carbon; and then lower the temperature to 25oC for test specimens. The IM specimens, being XRD and OM-checked firstly, are further pickled to obtain graphite that is also XRD-, OM- and ICP-analyzed to compare with graphite obtained from nodular cast iron and gray cast iron. The second part is about the vacuum arc re-melting (VAR) experiment of the specimens that are obtained in the first part. The effects of the number of VAR process and the addition of synthetic graphite on the DOG are checked with OM. The graphite samples of VAR specimens after pickled are checked with graphite production yield analysis, XRD for the comparison of the DOG, and ICP for the composition analysis.