| 摘要 |
PURPOSE:To improve the wear resistance and scuffing resistance of a locker arm by using low alloy cast iron contg. specific alloy elements and in which hard carbides consisting essentially of Cr is uniformly deposited into a pearlite or martensite matrix as the locker arm material. CONSTITUTION:The alloy cast iron contg., by weight, 2.5-3.7% C, 1.0-2.0% Si, 0.5-1.0% Mn, 10-20% Cr, 0.3-0.7% Ni, <0.3% P and <0.1% S or furthermore contg. one or more kinds among 1-10% W, Mo, V, Nb and Ta is used as the locker arm which is brought into contact with a cam shaft and valve at a high-surface pressure. Since said cast iron has a structure in which pearlite or martensite forms the matrix and the metallic hard carbides consisting essentially of Cr are uniformly dispersed and deposited in the matrix, the locker arm having excellent wear resistance and scuffing resistance can be obtd. |
