Segregation in castings is very complicated and the method of its determination by chemical analysis is almost inappropriate because of the sampling difficulties. The authors established the local spectrographic analysis method to meet the difficulties of sampling, and by means of this method, they carried out the experiment on the determination of segregation of silicon, manganese and magnesium in cast iron.
  The results obtained by the experiment have already announced in Repts. 1 and 2. Succeeding to the previously carried out experiment, the segregation in copper alloy castings was determined this time. Newly developed C. R. L. type universal source unit for local spectrographic analysis was used in this experiment. By means of this unit, good results have also been obtained for copper alloy castings.
  The determination was made on three different systems of alloys such as Cu-Sn, Cu-Ni and Cu-Pb.
  In the rapid-cooled Cu-Sn alloy castings, inverse segregation appeared at the outer and inner layers and normal segregation in the intermediate layer.
  Among these, inverse segregation at the outer layer would not appear gradually when the cooling rate was not fast enough and in this case, normal segregation appeared over the outer to intermediate layers. In cases of Cu-Ni and Cu-Pb systems, normal and inverse segregations were appeared in the outer and inner layers respectively.
  However, normal segregation was seen in the extremely inner layer in case of Cu-Pb alloy castings.
  The experimental results and the detailed theoretical considerations on the phenomena shall be stated in this report.