| 摘要 |
PURPOSE:To prevent wear due to permanent set by means of a piston ring, by internally chilling insert material in a sintered alloy, which hardness is high when temperature is high, to a circumferential wall of at least a top-ring groove among the piston-ring grooves of a piston in an aluminum alloy. CONSTITUTION:In a piston 1 in an aluminum alloy of machines such as a diesel engine produced by each mounting a top-ring groove 1a, in to which a gas seal- ring 3 is inserted, a second-ring groove 1b, into which a gas seal-ring 4 is similarly inserted, and an oil-ring groove 1c, into which an oil-seal ring 5 is inserted, from the upside onto an outer circumferential surface, insert material 6 in a sintered alloy is formed to a circumferential wall surface of at least the top-ring groove 1a. The insert material 6 is composed of alloy powder consisting of 8-25% Ni, 3.5-10% Cu, not more than 2.0% C (each is weight %) and the remainder, which is substantially Fe, and the density of the sintered alloy is set within a range of 5.5-6.8g/cm<3>. |
