The production, properties and automotive applications of austempered ductile iron

Ductile iron is an important material which is produced throughout the world and used for a wide range of applications. It is now well established that its as-cast mechanical properties can be significantly improved by using an austempering heat treatment to produce a new family of materials known as Austempered Ductile Irons (ADI). The improved properties enable ADI to replace steel castings and forgings in many engineering applications with significant cost benefits. This paper describes the key features of the production of ADI in the foundry and the options for carrying out the austempering heat treatment. The integration of machining operations and surface hardening treatments into the overall production route are also discussed. An overview is given of the effect of the process variables on the mechanical properties of ADI. Previous and current applications of ADI in the automobile sector are summarised and some of the challenges in developing the high volume production of ADI are considered.