What Are Definite Chilled Rolls?
Definite Chill Iron Rolls, also known as Clear Chill Iron Rolls, feature a white, super-hard working surface made of graphite-free cast iron. This material is produced from eutectic carbide and austenite, which provide exceptional hardness and high resistance to wear.
Beneath the white iron surface layer, the inner and narrow shaft regions of the rolls consist of hard gray iron. The transition zone between the white and gray iron layers exhibits a mottled appearance with patches of varying colors.
The white cast iron portion is significantly harder and stronger than the gray section, offering superior resistance to mechanical stress and wear encountered during rolling operations. This high compressive strength is maintained even under elevated temperatures, such as those in hot rolling mills.
When a fine surface finish is required, low-nickel chilled rolls can meet this demand. Rolls used in hoop and skelp mills must be selected with careful attention to strength and hardness to ensure compatibility with roughing, intermediate, and finishing stands.
Higher-alloy Clear Chill Iron Rolls perform effectively in two-high, three-high, or four-high mills used for processing quality ferrous and non-ferrous sheets, narrow strips, or sectional products. These rolls are particularly beneficial in finishing stands of rod mills, light section mills, and various sizes or earlier designs of continuous hot strip mills.
While Indefinite Chilled Rolls are also produced by iron casting, Definite Chilled Rolls are shaped and sized during the casting process while the iron is still in a molten or semi-solid state, before complete solidification into final forged rolls.
