High Performance Machining of Austempered Ductile Iron

This paper aims to establish some effective method for high-speed machining (HSM) of austempered ductile iron (ADI), a high performance structural material recently developed. Cutting performance of a number of tools and tool materials were evaluated experimentally in the study. Failure of the carbide inserts is due to diffusion and adhesion wear, and they cannot stand for HSM. Tool wear of the ceramic and CBN inserts is less sensitive to the cutting speed. While setting a circular insert free about its axis, namely the self-propelled rotary cutting, wear resistance of a carbide insert is enhanced significantly beyond those of the conventional tools tested including the ceramic and CBN inserts. Wear mechanism of the rotary tool and factors influencing its cutting performance are discussed. The rotary tool is found to be advantageous of high-cutting-speed and high-feed-rate machining, and hence a high-performance cutting tool for machining of ADI.