| 摘要 |
Copper alloy casting contains Cu: 58-72.5 mass %; Zr: 0.0008-0.045 mass %; P: 0.01-0.25 mass %; one or more elements selected from Pb: 0.01-4 mass %, Bi: 0.01-3 mass %, Se: 0.03-1 mass %, and Te: 0.05-1.2 mass %; and Zn: a remainder, wherein [Cu]-3[P]+0.5([Pb]+[Bi]+[Se]+[Te])=60-90, [P]/[Zr]=0.5-120, and 0.05[gamma]+([Pb]+[Bi]+[Se]+[Te])=0.45-4 (the content of an element 'a' is denoted as [a] mass %; the content of gamma phase is denoted as [gamma]% by area ratio; and an element 'a' that is not contained is denoted as [a]=0). The total content of alpha phase and gamma phase is 85% or more, gamma phase content is 25% or less by area ratio, and mean grain size in the macrostructure during melt-solidification is 250 mum or less.
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