| 摘要 |
PROBLEM TO BE SOLVED: To improve the thermal crack resistance in a break disk material for vehicles made of CV(compact vermicular) graphite cast iron high in mechanical strength and to improve its durability. SOLUTION: By allowing this material to have a chemical compsn. in the ranges of 3.6 to 4.2% C, 1.8 to 2.4% Si, 0.5 to 0.7% Mn, <=0.03% P, <=0.03% S, 0.004 to 0.015% Mg, 1.0 to 3.0% Ni and 0.3 to 0.7% Mo, controlling the contents of Cr and Cu to <=0.03% and executing prescribed heat treatment (two stage annealing or SR annealing), so that the ferrite rate in the base structure of the break disk exceeds 70%, the transformation of the structure into ferrite is promoted.
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