IRON-BASED SINTERED ALLOY FOR VALVE SEAT
PROBLEM TO BE SOLVED: To provide an iron-based sintered alloy for a valve seat, which has superior abrasion resistance and besides low aggressiveness to an opponent valve. SOLUTION: This iron-based sintered alloy has 10 to 20% by an area rate of first hard particles made of a Co-based intermetallic...
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Zusammenfassung: | PROBLEM TO BE SOLVED: To provide an iron-based sintered alloy for a valve seat, which has superior abrasion resistance and besides low aggressiveness to an opponent valve. SOLUTION: This iron-based sintered alloy has 10 to 20% by an area rate of first hard particles made of a Co-based intermetallic compound having particle diameters of 10 to 150 μm and a hardness of 500 HV to 800 HV (at the load of 0.1 kgf (hereafter the same)), and 15 to 35% by an area rate of second hard particles made of a Co-based intermetallic compound having a particle diameter of 10 to 150 μm and a hardness of 800 HV to 1,100 HV, dispersed in an amount of 25 to 55% by the total area rate in the matrix phase. The first hard particle preferably has a composition comprising, by mass%, 0.5-4.0% Si, 5.0-20.0% Cr, 20.0-40.0% Mo and the balance Co with unavoidable impurities; and the second hard particle preferably has a composition comprising, by mass%, 0.5-4.0% Si, 5.0-20.0% Ni, 15.0-35.0% Cr, 15.0-35.0% Mo and the balance Co with unavoidable impurities. The iron-based sintered alloy may disperse solid lubricant particles in addition to the hard particles in the matrix phase. COPYRIGHT: (C)2005,JPO&NCIPI |
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