Patent ID: 6305666
Filing Date: 2001-10-23
Classification: C22C,C23C,F01L

Abstract:
A valve seat made of Fe-based sintered alloy, the Fe-based sintered alloy comprising, on a weight percent basis:C: 0.5-2%, Si: 0.05-1% Co: 8-16% Cr: 2-8% Mo: 1.5-6% W: 1.5-6% Ni: 0.5-2% Nb: 0.05-1%, andcalcium fluoride: 1-15%, with the balance Fe and the inevitable impurities, wherein the Fe-based sintered alloy has a structure in which Co-based alloy hard particles A, which comprise Co--Mo--Cr alloy and have high temperature wear resistance, and Cr-based alloy hard particles B, which comprise Cr--W--Co--Fe alloy and have ordinary temperature wear resistance, are dispersed and distributed in the alloy steel base in a total amount of 6-26 area percent when they are observed on a structural photograph recorded by an optical microscope, wherein, in the alloy, the ratio of hard particles A to total hard particles is 25-75 area percent, and wherein the calcium fluoride particles are dispersed and distributed in the alloy steel base in an amount of 3-45 area percent, and the Fe-based sintered alloy has a porosity of 5-25%, said valve seat having excellent wear resistance.