IRON-BASE SINTERED ALLOY MATERIAL FOR VALVE SEAT INSERT AND METHOD FOR MANUFACTURING THE SAME

摘要

An iron-base sintered alloy material includes a matrix phase, Co base inter-metallic compound particles having hardness of 600 to 1200 HV, carbide-type particles having hardness of 400 to 700 HV, and optionally solid-lubricant particles, the particles being dispersed in the matrix phase. A matrix part including the matrix phase and the two kinds of hard-particles contains 0.3 to 1.5% by mass of C, and 10 to 50% by mass of one or more kinds selected from Si, Mo, Cr, Ni, Co, Mn, S, N, V, Ca, F, Mg, and O, the balance being Fe and unavoidable impurities. By dispersing, in the matrix phase, the Co base inter-metallic compound particles having high hardness, and the carbide-type particles having low hardness and low aggressiveness to mated material and increasing mechanical strength, wear-resistance can be improved with low aggressiveness to mated material and high radial crushing strength (350 MPa or more).

主权项

1. An iron-base sintered alloy material for a valve seat insert having excellent wear-resistance, comprising:
a matrix phase; first hard-particles; and second hard-particles, wherein the first and second hard-particles have hardness different from each other and are dispersed in the matrix phase, a matrix part including the matrix phase and the two kinds of hard-particles contains 0.3 to 1.5% by mass of C, and 10 to 50% by mass in total of one or more kinds selected from Si, Mo, Cr, Ni, Co, Mn, S, W, V, Ca, F, Mg, and O, the balance being Fe and unavoidable impurities, the first hard-particles are Co base inter-metallic compound particles having Vickers hardness of 600 to 1200 HV, the second hard-particles are carbide-type particles having Vickers hardness of 400 to 700 HV, the material has a structure including 2 to 45% by mass of the first hard-particles and 2 to 30% by mass of the second hard-particles, in which 10 to 50% by mass in total of the two kinds of hard-particles are dispersed, and the material has a density of 6.6 g/cm3 or more and radial crushing strength of 350 MPa or more.