抄録
Up to this time, it has been reported that the silumin (AC3A) has good castability and poor machinability. So, in order to improve the machinability of silumin, the turning test was carried out by adding a few elements. The results showed that the silumin is a material with a fairly large cutting resistance, and tool wear and is not easy to obtain good cutting surface. The machinability was examined by adding calcium and natrium effective for improvement of aluminium-silicon system eutectic alloys and phosphorus effective for refinement of the primary silicon in hyper eutectic alloys. By the addition of natrium, the machinability was improved considerably; for example, the cutting resistance decreased, the surface roughness and the tool wear was improved. On the other hand, by the addition of calcium, the cutting resistance increased slightly, but there was no favorable effect on the surface or the tool wear. And, by the addition of phosphorus, the tool wear increased, but there was no improvement in the cutting resistance, surface roughness and other properties.
