| 摘要 |
PURPOSE: Provided is a brass alloy for free cutting tool with improved machinability by reducing Pb content in the brass alloy while uniformly diffusing bismuth and selenium(Se) through the grain boundary of the brass alloy. Further, cerium(Ce) is added in the brass alloy so that grain size of the brass alloy is reduced and uniformly diffused in the alloy matrix. CONSTITUTION: The brass alloy of Cu-Zn for free cutting tool comprises Cu 56 to 62 wt.%, Pb 0.10 wt.% or less, Fe+Sn 1.0 wt.% or less, Bi 0.5 to 3.0 wt.%, Se 0.5 to 2.0 wt.%, Ce 0.25 wt.% or less, unavoidable impurities 0.5 wt.% or less and a balance of Zn.
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