| 摘要 |
PROBLEM TO BE SOLVED: To improve the thermal cracking resistance, wear resistance and mechanical property in a disc brake rotor consisting of flake graphite cast iron by forming it so that the average crack depth of the braking surface after a specified braking test is a specified value or less. SOLUTION: This disc brake rotor is formed out of flake graphite cast iron, and the flake graphite cast iron to be used preferably contains C 3.5-4.2 wt.%; Si 1.5-3.0 wt.%; Mn less than 0.5 wt.%; P 0.04 wt.% or less; S 0.12 wt.% or less; Cu 2 wt.% or less; Ni more than 0.5 wt.% and 3.0 wt.% or less; Cr more than 0.5 wt.% and 1.5 wt.% or less; Sn 0.01-0.05 wt.%; and the remainder of Fe and inevitable impurities, wherein Sn is concentrated in a width of 10-20Åin the base material boundary with graphite. Such a rotor is manufactured so that the average crack depth is 50μm or less when the brake test of braking the braking surface so as to have 600 deg.C in a non-asbestos pad and then allowing it to cool to 150 deg.C is repeated 600 times.
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