| 摘要 |
1148558 Making piston rings M KOEHLER 31 July 1967 [10 Oct 1966] 34996/67 Index F2T 37E1R [ Also in Division C7] A sintered split piston ring with a higher density on the inner periphery than on the outer periphery is made by compacting a metal powder such as Fe into a ring which has a greater height on its inner periphery than on its outer periphery, sintering the compact, then compressing the sintered ring so that it has the same height over the whole wall thickness, recompacting with a shaped ram so that the ring has a smaller height on its inner periphery than on its outer periphery, grinding to the required uniform height and cutting the slot and thermally stressing the ring. The initial compacting of the powder and the recompacting of the sintered ring produce an inclined annular surface at 15 degrees to the plane perpendicular to the ring axis. In an example a powder mixture fo 92À8% Fe, 3% Pb, 1À2% C, 3% Ni is compacted at 35 tons,sintered at 1080‹C., compacted at 100 tons, and recompacted with a bevelled ram at 80 tons. The density varies from 7À5 g/c.c. to 6À3 g/c.c. at the outer periphery. Chromium or vanadium may also be added to the iron powder. |
