AGI: Austempered Grey Iron

For grey lamellar graphite cast irons, the austempering process is an important opportunity for upgrading, similar to the one used for spheroidal graphite cast irons. At the end of this process, a metal matrix is obtained (ausferritic) with important improvements in the mechanical properties, especially in terms of hardness and mechanical strength.

The austempering heat treatment applied to a lamellar graphite cast iron adds unique characteristics to the material. An austempered casting in lamellar graphite cast iron provides mechanical strength comparable, if not greater, to that of a compacted graphite iron (CGI). The lamellar form of the graphite particles gives the AGI iron (Austempered Grey Iron) excellent thermal conductivity, similar to traditional lamellar graphite cast iron. The combination of the ausferritic matrix with lamellar graphite cast iron gives AGI iron the same characteristics as the ferrous material with higher vibration damping. Its wear resistance is excellent thanks to the synergy between the matrix properties (PITRAM effect) and the lubricating capability of the lamellar graphite.