The prensence of free graphite flakes in the working layer distinguishes indefinite chill cast iron rolls from clear chill cast iron rolls. Free graphite improves the elastic properties of the material, reduces the effect of specific rolling loads and favours heat exchange by increasing the resistance to thermal fatigue. The structure is also made up of cementite which icreases wear resistance, in a pearlitic or baintic/martensitic matrix. Rolls may be supplied as monobloc or as compound. When high hardness in the working layer and highly resistant core metal material to high rolling pressure is required the use of compound (double pored) rolls is recommended.