Kabushiki Kaisha Riken

Akiko Shimada

Hiroji Henmi

The present invention provides a valve seat of a Co-free, sintered iron-based alloy having excellent heat resistance, oxidation resistance and wear resistance, as well as excellent machinability, which is usable for internal combustion engines using a gas fuel. The valve seat is produced by using a prealloy containing 12% or more by mass of Cr in a matrix for, and hard particles having high strength and hardness at high temperatures are used, such that the entire valve seat has a composition comprising by mass 5.0-20.0% of Cr, 0.4-2.0% of Si, 2.0-6.0% of Ni, 5.0-25.0% of Mo, 0.1-5.0% of W, 0.5-5.0% of V, 1.0% or less of Nb, and 0.5-1.5% of C, the balance being Fe and inevitable impurities.

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Kumagaya, Japan

Akiko Shimada