Patent ID: 11951547
Assignee: TPR CO., LTD.
Field: Materials, metallurgy (Chemistry)
Classification: CPC B  C  F | IPC B  C  F

Claim 0:
1. A method of producing a valve guide made of an iron-based sintered alloy, the method comprising the steps of:
molding raw material powder including at least one kind of calcium compound selected from the group consisting of calcium carbonate and calcium sulfide, and diffusion-alloyed powder consisting of core iron powder and Cu bonded to the core iron powder through diffusion to obtain a molded body, and
sintering the molded body, to thereby produce a valve guide made of an iron-based sintered alloy, wherein the sintered alloy includes MoS2, and the molded body having a density of about 6.55 g/cm3 to about 7.15 g/cm3,
(1) the raw material powder having a content of a Cu component falling within a range of from 24.2 mass % to 35 mass %,
(2) a thermal conductivity at 400° C. of about 40 W/mK to about 60 W/mK,
(3) a ratio of a Cu component derived from the diffusion-alloyed powder consisting of core iron powder and Cu bonded to the core iron powder through diffusion with respect to the Cu component contained in the raw material powder being 45% or more;
wherein the valve guide has a structure including pores and a Cu phase, and a pore area ratio of the pores is 3% or more and 15% or less and a Cu area ratio of the Cu phase is from 11% to 36%.