| 摘要 |
PROBLEM TO BE SOLVED: To provide a material of a rotor for a disc brake, which has adequate castability, is easily worked, and has high productivity, high heat resistance and high cracking resistance. SOLUTION: This material of a rotor is a gray cast iron having a chemical composition comprising, by weight ratio, 3.75-3.95% C, 1.8-2.2% Si, 0.5-0.8% Mn, 0.1% or less P, 0.08-0.15% S, 0.2-0.7% Mo, 0.2-0.6% V, 1.5% or less Cu, and 0.1% or less Cr and the balance substantially Fe. The method for casting the material includes controlling a temperature so that a cooling period of time after having started teeming of the molten metal and before the molten metal reaches 730 to 750°C of the A<SB>1</SB>transformation temperature is 20 to 50 minutes, by using a casting method and a technique such as die cooling. In the above method, a cooling rate for the molten metal is in the range of 5 to 45°C/minute. COPYRIGHT: (C)2005,JPO&NCIPI
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