Effect of Copper and Heat Treatment on Microstructure of Austempered Ductile Iron

Austempering of ductile iron was described in this paper. All the influential parameters during production of ADI have been clarified. The literature data indicate that each heat treatment parameter has a certain influence on the final microstructure and, therefore, on the mechanical properties of ADI. Effect of alloying elements in ductile iron has been investigated. Based on the current knowledge and austempering heat treatment parameters, a plan of experiments was designed. In this paper, the influence of the most important heat treatment parameters and copper content on the final microstructure of ADI was determined. By varying the copper content, it is possible to influence the volume fraction of retained austenite in ADI. The results of the planned research could serve as a basis for the development of unique mathematical models that would include the influence of each individual parameter of heat treatment and copper content on the microstructure of ADI. The mathematical models thus developed would serve to predict the final mechanical properties depending on the input parameters of the heat treatment and the copper content.