Lamellar Graphite Cast Iron

It is a type which most of the carbon in its composition is found in the form of free graphite sheets (lamellar-flake) after solidification. When gets broken, its surface has a sooty gray appearance. This cast iron, which is dark in color due to graphite, is called lamellar graphite cast iron or “GRAY CAST IRON”.

Besides the main structure of iron, there are carbon, silicium, manganese, phosphorus and sülfür in the sytructure of gray cast iron. These elements are generally come from “RAW IRON (pik)”. Sulfur is an undesirable element, but small amount of phosphorus is beneficial in this composiition.

Heat Treatments Applied to Lamellar Graphite Cast Iron

Gray cast iron can be quenched and tempered by heat treatments similar to those applied to steel. For example, the wear resistance of cylinder liners can be increased by boosting the hardness to 45-55 HRC by hardening and tempering. Better machinability, higher wear resistance and strength are the main advantages obtained by heat treatment.