| 摘要 |
PURPOSE:To improve abrasion resistance, heat conduction and anti-loosening properties by a method wherein a double layered structure of first layer, including the abutting surface of a valve, and second layer, supporting the first layer, is formed and respective layers are constituted of specified constituents such as Ni or the like consisting of specified weight ratios. CONSTITUTION:The iron base sintered alloy of double layered structure, consisting of the first layer 1 including the abutting surface of the valve and the second layer 2 supporting the first layer 1, is formed and both layers 1, 2 are connected by sintering metallurgically. The first layer 1 is constituted in weight ratio of the constituents of Mo; 2.5-15%, Co; 1-15%, Ni; 1-15%, Co; 0.2-0.7% and balance of Fe and impurities up to 2% while ferro-molybdenum having average particle diameter 10-30mu are dispersed uniformly in the constitution. The second layer 2 is constituted in weight ratio of the constituents of Ni; 1-5%, C; 0.2- 0.7% and balance of Fe and impurities up to 2%. Further, the difference of the amount of C between said both layers 1, 2 is specified to up to 0.3%. |
