MACHINING OF GRAY CAST IRONS AND COMPACTED GRAPHITE IRON

Abstract: The aim of this paper is to compare the machinability of gray cast iron and compactedgraphite iron (CGI), in terms of tool life and microstructure. Two gray cast irons with differentgraphite morphologies and one CGI were tested. After the tool life tests with carbide and CubicBoron Nitride (CBN) inserts, microstructural changes on the machined surfaces wasinvestigated and SEM analysis of the inserts were performed. The results show that CBNperformed much better than Carbide tools when machining gray cast irons but did not workwhen machining CGI due to high diffusional wear. The shorter and thicker graphite flakes forone of the gray cast iron caused different chip contact and wear mechanism on the inserts. Thecomparison of machinability and tool wear gave better understanding of the wear mechanism ofCGI