摘要 |
This invention relates to a method of making a valve lifter or the like wherein elemental iron powder is blended with smaller sized powders of manganese, molybdenum, and nickel, or sources of these metals, the resulting mixture is pressed into a coherent preform which is then sintered to cause solid state diffusion and alloying to occur within the preform. The sintered preform is then pressed into a shape which approaches the theoretical density of the metal and has a nearly uniform density carburized and heat treated, the pressing being carried out at ambient temperatures to produce a valve lifter or similar article having superior wearing properties at a lower cost, when compared with present materials and methods of manufacture. |