The purpose of this study is to refine Al-Fe-Si compounds in aluminum alloys by ultrasonic radiation at a temperature higher than the crystallization temperature of Al-Fe-Si compounds. The ultrasonic refining effect was examined using Al-Si-Fe-Mn alloys without or with the addition of chromium and titanium. The experiments included melting 1kg of alloys in a crucible, dipping an ultrasonic horn into the melt, radiating ultrasound into the melt for 30s at a temperature at least 50K higher than the crystallization temperature of Al-Fe-Si compound, holding the melt for 20s and casting it into a copper mold by gravity casting. The refining effect of Al-Fe-Si compounds was found to be improved by the addition of chromium and titanium. EPMA analysis was applied to elucidate the reason. The results revealed that the ultrasonic radiation accelerates the formation of Cr-containing compounds and Ti-containing compounds acting as heterogeneous nuclei of the Al-Fe-Si compounds. The analysis results suggested that the refined Al-Fe-Si compound is composed of the K₅ phase. The heterogeneous nuclei of the K₅ phase was presumed to be the Al-Cr-Si β phase and Al-Si-Ti τ₁ phase, respectively.

  Solidification begins during pouring in casting processes, and the pouring rate influences the solidification pattern and soundness of products. In this research, the combined simulation of fluid flow and solidification simulation was performed based on the MPS method (a particle method) to analyze the behavior of shrinkage formation from the beginning of pouring to the end of solidification, and the influence of pouring rate on the solidification pattern and shrinkage shape of pure Al casting was investigated. Solidification simulation and stabilized flow simulation programs based on the particle method were combined considering the temperature-dependency of density. The proposed method was applied to shrinkage formation analysis based on the influence of pouring velocity on the shrinkage formation behavior. The results showed that the depth and shape of shrinkage agreed well with corresponding experimental results. The shrinkage formation behavior could also be directly calculated.

  The behavior of hot-tearing and solidification structures in Mg-0～12mass%Al-0～10%Ca alloys cast into an I-beam shaped mold were investigated by XRD measurement and OM, SEM-EDS observation. In the as-cast state of all alloys, the solidification structures mainly consisted of the primary crystallized α-Mg and secondary crystallized eutectic, such as Mg₂Ca, Mg₁₇Al₁₂ and Al₂Ca phases. The shape of the α-Mg phase changed from celler to dendritic when the Al and Ca contents were increased. The area fraction of the hot-tearing region decreased with the increasing amount of crystallized eutectic phases with increasing Al and Ca contents, due to the healing effects on cracks at the hot-tearing portions. The temperature range between the liqidus and solidus lines influenced the hot-tearing.

  This paper presents an advanced control system for tilting-ladle-type automatic pouring machines used in the metal casting industry. In order to pour liquid from the lower position as much as possible, an approach for ladle trajectory generation is proposed in this paper. The proposed approach was considered for controlling the falling position of the outflow liquid and avoid collision between the ladle and obstacles. Three pouring modes derived from the positional relation between the ladle and obstacles were proposed for the approach. The switching of the pouring mode was also proposed to shift the lowest pouring mode depending on the pouring conditions and ladle posture. The analytical algorithm of the falling position control system was established. The effectiveness of the proposed control system was validated through experiments using a laboratory automatic pouring machine with a monitoring system.

  The machinability of austempered spheroidal graphite cast iron made by continuous casting (A-FCD600) was investigated. In this study, spheroidal graphite cast iron made by continuous casting (FCD600) was used to examine the influence of the austempering on machinability. In addition, austempered gray cast iron made by continuous casting (FC250) was used to examine the influence of the morphology of graphite on machinability. From the results of a tool wear test using continuous turning, the machinability decreased in the order of FC600, A-FC250, and A-FCD600. When relative machinability ratings between each material were calculated using tool life equations decided by the result of the tool wear test, the machinability of A-FCD600 was approximately 1.9 times inferior to FCD600, and approximately 1.3 times inferior to A-FC250. One characteristic of A-FCD600 was that its mechanical properties were relatively near steel. Therefore, a similar tool wear test was carried out with a P10 cemented carbide tool for steel. In this case, the tool life extended 25% compared to the K10 cemented carbide tool for cast iron. These results suggest that tool life can be improved in A-FCD600 cutting when tools for steel are used.