| 摘要 |
Disclosed is a sintered valve guide guide formed of a sintered alloy consisting essentially of 3.5 to 5% copper, 0.3 to 0.6% tin, 0.04 to 0.15% phosphorus, 1.5 to 2.5% carbon and the balance iron, by mass, and as occasion needs, further containing 0.46 to 1.41% metal oxide, and MnS and/or magnesium silicate. The metallographic structure has: a matrix containing a pearlite phase, a Fe-P-C compound phase and a Cu-Sn alloy phase; pores; and a graphite of 1.2 to 1.7% by mass of the sintered alloy. In the cross section, the ratio of the pearlite phase to the matrix is 90 area % or more, the ratio of the Fe-P-C compound phase is 0.1 to 3 area % of the cross section, the ratio of the Cu-Sn alloy phase to the cross section is 1 to 3% by area, and the ratio of a portion of the Fe-P-C compound phase having a thickness of 15 microns or more is 10 area % or less of the whole Fe-P-C compound phase.
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