Effect of Chemical Composition and Heat Treatment on Properties, Microstructure and Machinability of Austempered Ductile Iron

Austempered ductile irons (ADI) have attractive properties such as high strength, ductility, toughness and good wear resistance, therefore have special situation in transport industry, and substitute to steel parts. These properties can be achieved upon adequate chemical composition and heat treatment which yields optimum microstructure and mechanical properties. The most problem in application of these materials is low machinability which increasing cost of machining products. In this paper an investigation has been conducted on ADI's with different chemical compositions and heat treatments. The microstructure developed throughout these treatments has been identified by means of metallography microscopy. The abrasion of machining tool is a criteria for comparing of machinability of specimens. Based on these results an optimal processing window has been established for production ADIs.