Comparative study of the machinability of austempered and pearlitic ductile irons in drilling process

Abstract

The aim of this work is to analyze the austempered ductile iron (ADI) feasibility to substitute the conventional ductile iron in automotive components manufacture. This analysis was based on machinability criteria comparison of thrust force, torque and cutting power of two ADI grades (ISO 800-10 and ISO 1.050-6) with FE 70003 pearlitic ductile iron as-cast. Cutting speed, feed rate and cutting fluid application technique, besides the work material, were varied in the drilling tests. The tool used in the tests was the K20 cemented carbide twist drill coated with multilayers of TiN/TiAlN with diameter of 10 mm. The results showed that the ISO 800-10 ADI grade was the material with highest machinability followed by FE 70003 pearlitic ductile iron as-cast and then by ISO 1.050-6 ADI grade. It was concluded that the machinability of the materials studied is thereafter closely related to their microstructures. Therefore, ADIs obtained by DI partially austenitized have excellent potential to substitute ductile irons based on the machinability criteria evaluated.