Iron-base sintered alloy for valve seat and method of making the same
AssigneeRiken Piston Ring Industrial Co. Ltd.
InventorKazutoshi Takemura
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Abstract
An iron-base sintered alloy especially suitable for valve seat manufacture having excellent wear resistance and being able to be machine-cut is provided. The alloy is produced by combining specifically atomized pre-alloyed powder, iron powder, nickel powder and graphite powder by means of compacting and sintering processes, and has a microstructure comprising pearlite and globular hard alloy phase formed with said atomized pre-alloyed hard alloy powder uniformly dispersed in said pearlite and martensite surrounding said hard alloy phase.
Claims2
Wear resistant and machinable sintered iron-base alloy especially suitable for valve seat manufacture, having a chemical composition by weight of 0.6-2.1% carbon, 1.0-8.0% chromium, 0.5-4.0% tungsten, 2.0-12.0% cobalt, 1.0-5.0% nickel and balance essentially iron, having a microstructure comprising pearlite and globular hard alloy phase uniformly dispersed in said pearlite with martensite surrounding said hard alloy phase being formed with atomized powder of pre-alloyed hard metal having chemical composition by weight of 1.0-3.0% carbon, 20-40% chromium, 10-20% tungsten and 40-60% cobalt.
Method of producing sintered iron-base alloy especially suitable for valve seat manufacture, comprising the steps of mixing 5-20% by weight of pre-alloyed and atomized hard alloy powder having chemical composition by weight of 1.0-3.0% carbon, 20-40% chromium, 10-20% tungsten and 40-60% cobalt;
- 0.6-1.5% graphite powder, 1.0-5.0% nickel powder and remainder of iron powder;
- compacting the mixture into a desired shape;
- and sintering said compacted mixture at a temperature ranging 1100.degree. to 1200.degree. C., then cooling said compacted and sintered mixture to a room temperature.
Dependencies are inferred from the claim text.