Compared to Clear Chill Roll where the chill-zone is graphite-free clear white, Indefinite Roll is cast using such proportions of silicon, chromium, nickel and molybdenum that the working face is no longer completely white but contains a small amount of very finely divided graphite flakes gradually increasing from face to core with corresponding decrease in the amount of carbide. The rolls are to ensure minimum sacrifice of clear chill while achieving maximum functional depth.
The transition from Chill to graphite being more smooth, the gradual change in hardness associated with the indefinite-chill structure allows deeper grooving. Thus Indefinite Chill Rolls are superior in biting performance and have enough strength and resistance against thermal shock occuring at the time of accident in the rolling operation compared to Clear Chill Rolls.
Roll of this type have hardness up to about 70 Shore °C can be grooved for use in roughing and finishing stands, for processing sections such as T-bars and U-sections, and for roughing and intermediate rolls of wire and rod mills.