Process for producing a sintered product of copper-infiltrated iron-base alloy and a two-layer valve seat produced by this process

摘要

A process for producing a Cu-infiltrated sintered Fe-base material without requiring a separate Cu infiltration step is disclosed. The process comprises the steps of preparing two powder mixes, one having a predetermined composition with a powder of infiltrating material containing Cu powder or Cu alloy powder as the primary component, and the other having a predetermined composition without said powder of infiltrating material; pressing the two powder mixes into a compact having said powder of infiltrating material present locally; and sintering the compact under ordinary conditions so as to cause the infiltrant to penetrate into the infiltrant-free area simultaneously with the sintering. Also disclosed is a two-layer valve seat produced by this process. One layer of the valve seat accounts for the principal part of the seat and is made of an Fe-base sintered material containing Cu or Cu alloy as an infiltrant, and the other layer provides a layer to contact the valve and is infiltrated with Cu through pores during the sintering.