Indefinite Chill Rolls

Hardness that fades gently, so grooves can go deeper.

Hardness: Up to about 70 Shore

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Indefinite chilled iron rolls are cast high-nickel rolls with a fine deposit of graphite at the surface. Their hardness can be tuned by adjusting the chemical composition or by changing the casting method, so the roll can be adapted to a particular application.

The graphite gives these rolls strong resistance to thermal shock. The microstructure is a pearlitic matrix with finely dispersed graphite flakes and eutectic carbides, with the carbides lying perpendicular to the surface of the roll and the graphite running in the same direction.

The transition from chill to grey is smooth. That gradual change in hardness allows deeper grooving, with hardness of up to about 70 Shore.

Graphite at the surface gives strong resistance to thermal shock, and the gradual hardness drop allows deep grooves.

Chemical composition

C	Si	Mn	Cr	Ni	Mo	Hardness (Shore C)
3.00-3.50	0.80-1.50	0.55-1.20	0.50 max	0.50 max	0.10 max	60-65
3.00-3.50	0.80-1.50	0.55-1.20	0.50-1.00	0.50-1.00	0.10-0.20	65-70
3.00-3.50	0.80-1.50	0.55-1.20	1.00 max	1.00-1.25	0.20-0.30	70-75
3.00-3.50	0.80-1.50	0.55-1.20	1.00 max	1.25-1.50	0.30 max	75-80