Brake disk and method for manufacturing the same

Abstract

Disclosed are a brake disk and a method for manufacturing the same. In particular, the brake disk may include a friction surface formed of cast iron, and the friction surface of the brake disk is divided into a plurality of sections in a circumferential direction. Preferably, an average of the numbers per unit area of eutectic cells formed on surfaces of the sections may not be greater than 300 ea/cm2.

What is claimed is: 
     
         1 . A brake disk having a friction surface formed of cast iron, wherein the friction surface of the brake disk comprises a plurality of sections in a circumferential direction, and an average of numbers per unit area of eutectic cells formed on surfaces of the sections is not greater than about 300 ea/cm 2 . 
     
     
         2 . The brake disk of  claim 1 , wherein a deviation of the numbers per unit area of the eutectic cells formed in the plurality of sections is not greater than about 60 ea/cm 2 . 
     
     
         3 . A method of manufacturing a brake disk, comprising:
 casting a brake disk comprising a friction surface; and   grinding the friction surface of the brake disk in a thickness direction such that a number per unit area of eutectic cells formed on the friction surface of the brake disk is not greater than about 300 ea/cm 2 .   
     
     
         4 . The method of  claim 3 , wherein in the grinding of the friction surface of the brake disk in the thickness direction, when an average contraction ratio at which the brake disk is contracted in the thickness direction while the brake disk is casted is less than about 1.5%, one side of the friction surface is ground by a degree that is not less than about 2 mm and is less than 3 mm. 
     
     
         5 . The method of  claim 3 , wherein in the grinding of the friction surface of the brake disk in the thickness direction, when an average contraction ratio at which the brake disk is contracted in the thickness direction while the brake disk is casted is not less than about 1.5%, one side of the friction surface is ground by about 3 mm or greater. 
     
     
         6 . A vehicle comprising a brake disk of  claim 1 .