| 摘要 |
PROBLEM TO BE SOLVED: To product a free-cutting aluminum alloy having excellent machinability without the addition of lead and to provide a method for producing the alloy material thereof. SOLUTION: This free-cutting aluminum alloy contains, as essential components, by weight, 5.1 to 6.0% Cu, 0.1 to 1.0% Zn and 0.5 to 1.5% Sn, and the balance Al with impurities. Moreover, in addition to the above essential components, at least one kind among Si, In and Bi is added, or at least one kind of Mg and Mn is added, or both are added. Furthermore, the free-cutting aluminum alloy material is produced by subjecting a billet composed of the above free-cutting aluminum alloy to homogenous treatment at 200 to 545 deg.C, extruding this billet at an extrusion temperature of 300 to 500 deg.C at an extrusion product rate of >=5 m/min, moreover drawing the same at a reduction of >=5%, thereafter executing solution treatment at 300 to 545 deg.C, furthermore subjecting the same to natural aging treatment for >=1 hr and, if required, executing artificial aging treatment at 100 to 250 deg.C for 1 to 30 hr.
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