Shot peening of austempered ductile iron

Abstract

Austempered ductile iron (ADI) is a type of heat-treated cast iron, which offers numerous positive advantages including: good combination of mechanical properties and damping characteristics, lower density than steel and the possibility of casting components into near-net shape. However, surface engineering techniques are necessary to extend the use and prolong the lifetime of ADI engineering components. One such treatment for improving the bending fatigue strength of ADI is shot peening. This treatment creates compressive residual stresses and high dislocation densities at the surface of the treated components. However, the shot peening process is not always beneficial in improving the tribological characteristics of ADI. Its behaviour depends on the type of wear mechanism, applied loads, lubrication, heat treatment process parameters and the resulting surface finish of the components. This chapter will look into the effect of shot peening on ADI in more detail and will delve into a case study, which was carried out to analyse the bending fatigue resistance and tribological characteristics of Cu-Ni-alloyed ADI.