Compacted graphite iron (CGI)

Compacted graphite iron occupies an intermediate position between lamellar and spheroidal graphite iron: the compact graphite shape gives it superior mechanical strength and toughness compared to grey iron, while maintaining a much higher thermal conductivity than spheroidal iron.
This unique combination makes it the material of choice for cylinder heads in high-performance engines, heavy-duty diesel engine blocks, and components subject to high cyclic thermal gradients.