Microstructure, Mechanical Properties and Flowability of Ultra Low Silicon Hyper-Eutectic Flake Graphite Cast Iron

摘要

In this study, we reproduced the hyper-eutectic cast iron made at the end of the Edo period, and considered its new possibility.It was found that foundry men of that period made non-chill hyper-eutectic cast iron even at very low silicon content. As for f50 x 250 mm T.P, the tensile strength of C4.53% flake graphite cast iron is 107 MPa which is very low for cast iron. It is thought that the produced thick cannon most probably burst in actual combat with this material.The melt's flow ability is the best in the eutectic composition but deteriorates suddenly when entering the hyper-eutectic composition, due to the formation of Kish graphite. Plate type carbide forms when silicon content is low and with quick cooling, in the hyper-eutectic composition. It is thought to form, due to the very slow C diffusion from the matrix to the free graphite, during the eutectoid transformation. Test pieces having plate type carbides shows excellent damping capacity.