Patent ID: 11512370

Abstract:
This free-cutting copper alloy contains Cu: 58.5 to 63.5%, Si: more than 0.4% and 1.0% or less, Pb: 0.003 to 0.25%, and P: 0.005 to 0.19%, with the remainder being Zn and inevitable impurities, a total amount of Fe, Mn, Co and Cr is less than 0.40%, a total amount of Sn and Al is less than 0.40%, a relationship of 56.3≤f1=[Cu]−4.7×[Si]+0.5×[Pb]−0.5×[P]≤59.3 is satisfied, constituent phases of a metal structure have relationships of 20≤(α)≤75, 25≤(β)≤80, 0≤(γ)<2, 20≤(γ)1/2×3+(β)×(−0.5×([Si])2+1.5×[Si])≤78, and 33≤(γ)1/2×3+(β)×(−0.5×([Si])2+1.5×[Si])+([Pb])1/2×33+([P])1/2×14, and a compound including P is present in β phase.