Turning of Austempered Ductile Iron with ceramic tools

Abstract

Austempered ductile iron castings (ADI) are characterized by the high strength and resistance to fatigue, impact, and wear. ADI mechanical properties are obtained by performing a heat treatment on ductile iron casting. Thus, the so-called ausferrite microstructure is achieved. However, heat treatment significantly affects ductile casting machinability. A precise determination of ADI microstructure, on the one hand, and to choose correct machining process parameters and tool wear control on the other, are essential to optimize cutting processes and for the introduction of ceramic inserts. Ceramics are an alternative to carbide tools. In this paper, ceramic tools for the dry turning of ADI castings are studied. Thus, different technical ceramics were analyzed, identifying the dominant wear mechanism and evolution. Tool wear rate magnitude was determined indirectly by the variation of cutting force along machining time. Finally, different tests helped to study ceramics wear sensitivity with respect to cutting parameters. Mixed ceramics of Al2O3 with TiC showed the best performance, followed by SiAlON ones.