Partner attack Characteristic is small the copper impregnation Fe basic sintering alloy make valve seat

摘要

PURPOSE:To reduce attacks upon mating member and to improve wear resistance and fitting property by constituting the valve seat of a structure in which the grains of Co-base alloy are dispersed into a matrix of an Fe-base alloy with a specific composition and an Fe-base sintered alloy impregnated with copper. CONSTITUTION:The grains of a Co-base alloy consisting of, by weight, 5-15% Cr, 20-40% Mo, 1-5% Si, and the balance Co with inevitable impurities and having 500-1000 Vickers hardness are dispersedly incorporated by 5-20% into an Fe-base alloy matrix which has a composition consisting of 0.1-3% Mo, 0.1-3% Ni, 1-10% Co, 0.5-5% Cr, 0.5-1.5% C, 0.1-2% Nb, and the balance Fe with inevitable impurities and also has a structure composed principally of pearlitic phase and in which Vickers hardness is regulated to 150-500. A valve seat is formed by combining an Fe-base sintered alloy prepared by infiltrating copper into a base material of Fe-base sintered alloy of 10-20% porosity with the above structure.