Free-cutting copper alloy and method for manufacturing free-cutting copper alloy

Abstract

This free-cutting copper alloy includes Cu: more than 61.0% and less than 65.0%, Si: more than 1.0% and less than 1.5%, Pb: 0.003% to less than 0.20%, and P: more than 0.003% and less than 0.19%, with the remainder being Zn and unavoidable impurities, a total content of Fe, Mn, Co, and Cr is less than 0.40%, a total content of Sn and Al is less than 0.40%, a relationship of 56.5≤f1=[Cu]−4.5×[Si]+0.5×[Pb]−[P]≤59.5 is satisfied, constituent phases of a metallographic structure have relationships of 20≤(α)≤80, 15≤(β)≤80, 0≤(γ)<8, 18×(γ)/(β)<9, 20≤(γ)×3+(β)×([Si])≤88, and 33≤(γ)×3+(β)×([Si])+([Pb])×35+([P])×15, and a compound including P is present in β phase.