The aim of this project is to increase the productivity and efficiency for machining Austempered Ductile Iron (ADI) by innovative cutting tools, adapted cutting strategies and material optimisation. Particularly, the processes drilling, milling and threading are considered. Adapted cutting tools (drills, mills and taps) will be developed for machining ADI concerning their macro and micro structure, including new coatings. Additionally, the effects of different ADI-grades, adapted heat treatment and chemical composition of the material on its machinability will be analyzed in order to enhance the machinability characteristics of ADI. One critical field for the European automotive industry it is the reduction of CO2 emissions. The only approach to antagonize is to significantly reduce the weight of moving parts. To reach the target, “extreme” materials are required which, in contrast to conventional materials show an increased power density, meaning a larger ratio of strength to weight.
At present, Austempered Ductile Iron (ADI) is one of the most capable materials in the field of cast irons. Even if the application of light metals, plastics and composites has increased in the past years in many fields of applications, cast iron receives more and more attention in the field of construction materials [DGV98, DÖP00, Hup03). Low production costs, high material utilisation level, high ratio of strength to weight, high freedom of part design, high ductility, good vibration damping, recycling friendliness and a big range of different material grades with varying mechanical and thermal properties are reasons for a big field of applications for ADI, especially in the automotive and engineering industry. The high tensile strength of ADI (800-1400 N/mm², depending on the grade) combined with a high elongation at break (up to 10%), higher wear resistance and better damping characteristics compared with steel of the same hardness (Figure 1, Table 1) allows the possibility of upgrading existing components of ductile iron and substitute parts made of steel and aluminium. In comparison to conventional cast irons and other materials, parts can be designed with thinner walls, lower costs and lower weight for the same application and stiffness.