S. Putatunda, S. Kesani, Wayne State University, Detroit, MI

Summary: In this investigation, Austempered Ductile Iron (ADI) with a fully ferritic microstructure (austenite free) has been developed by applying a novel heat treatment process conceived by these investigators. This novel process consists of austempering and isothermal tempering below the inter-critical (A1) temperature. This process has resulted in a new class of structural materials with a fully ferritic microstructure which are not commercially available. This microstructure has imparted excellent machinability and thermal shock resistance together with good ductility and toughness. ADI with completely ferritic microstructure are not commercially available. Our novel process could possibly be used to produce structural steels with fully ferritic microstructure and thus it will create inexpensive structural materials with excellent machinability and thermal shock resistance. This will also result in significant cost saving in machining operations.