Compacted Graphite Iron is an engineered form of cast iron. It is at least 75% stronger and 45% stiffer than the standard grey cast iron and aluminium alloys. More importantly, CGI provides double the fatigue strength of grey iron and up to five times the fatigue strength of aluminium at elevated temperatures. The improved properties of CGI enable design engineers to reduce the size and weight of components, and/or to increase operating loads. CGI is ideally suited to components that have simultaneous mechanical and thermal loading, such as cylinder blocks and heads, exhaust manifolds, turbocharger housings and clutch components.
Compacted Graphite Iron allows engine designers to improve performance, fuel economy and durability while reducing engine size, weight, noise and emissions. CGI enables automotive engines to be 10-20% lighter than conventional cast iron engines and 10-20% shorter than aluminium engines. The reduced length means that all of the components that span the length of the engine are also shorter, and therefore lighter. The net result is that fully assembled CGI engines can effectively be the same weight as, or even lighter than, aluminium engines. CGI also allows for 10-20% increased specific performance (kW/litre), 75-100% improved durability, and 5-10% reduced operating noise. The strength and stiffness of CGI maintains the dimensional accuracy of the cylinder bore and allows engines to satisfy emissions legislation throughout the life of the vehicle.