Friction and wear properties of graphite cast iron for hot working rolls

Two-disc type wear tests and disc-block type adhesion tests were conducted on graphite cast iron roll material in hot rolling mills for the purpose of improving its wear and adhesion resistance. The effects of the amount of graphite in the microstructure on friction and wear behaviors of the graphite cast iron under the mild and severe conditions were studied. Austenic stainless steel SUS 304 and carbon steel S 45 C were selected as the mated materials. The coefficient of friction is decreased by increasing the amount of graphite in the microstructure, independent of the mated materials and the adhesion test conditions. The wear rate can be decreased by slightly increasing the amount of graphite, but it is increased by greatly increasing the amount of graphite, except for the case of mated material S 45 C under mild wear conditions where the wear rate is increased by increasing the amount of graphite. A new friction and wear model is proposed which successfully explains these experimental results.