Alの鋳造に関する研究（第1報）Casting CrackにおよぼすFeおよびSiの影響

抄録

The effect of Fe or Si upon casting cracks of aluminium ingots were investigated by measuring shrinkages or cracks which were found at casting into a particular metal mould (See Fig. 1). Results obtained are as follows: (1) The higher the casting temperature, the larger the shrinkage, and so the casting at higher temperature promotes the opportunity for cracks. (2) According to the casting temperature or the purity of Al used, there is a proper range for the mould temperature. (3) By the addition of Fe, up to 0.7% the shrinkage decreases 0.7% and the addition of Fe protects ingots from casting cracks, and yet does not affect upon the intercrystalline brittleness of Al. (4) By the addition of Si, up to 0.6∼0.7%, the shrinkage increases but addition over that percentage it decreases the shrinkage. Furthermore, the intercrystalline brittleness increases remarkablly by the addition of Si. (5) Cracks which were found in such cases as hindrance of free contraction, become finer by slow cooling but langer by the rapid cooling, and also the higher the purity of Al, the finer they become generally.