Abstract
In order to develop the free-cutting alloys of Al-Cu and Al-Mg2Si groups, various studies were carried out, by changing the chemical compositions and quantities. And the results shown below were obtained in the range of this experimental condition. (1) In view of the machinability of Al-Cu group alloys, Al-0.2Fe-4.5Cu-0.5Pb-0.25 Zn-0.35 Si-0.3Bi was regarded as the suitable chemical compositions and quantities. (2) As for the Fe and Zn lements in Al-Cu alloys, the cutting force and cutting temperature were remarkably improved in the case of 0.2%Fe-0.25%Zn as compared with the case of 0 or 0.6%Fe and 0.01%Zn. (3) In the relation among the quantities of Si, Cr, Zn, Fe, and Mn elements in Al-Mg group alloys, A1-0. 3Si-4.5Mg-0.3Zn-0Fe-0Mn showed the best machinability. (4) The machinability of Al-Mg2 Si group alloys was improved most when the chemical compositions and quantities were Al-1.0(Sn+Pb)-1.5 Mg2Si-0.5Mn-0.4Cu-0.05Ca-0.2Cr. (5) The addition of 1%(Sn+Pb) showed the large improvement effect for the disposal of chips, cutting force, cutting temperature and cutting ratio in Ai-Mg2Si alloys.
