This paper presents the modelling and pouring control of automatic pouring process with a fan-type ladle to improve the productivity of factories, safety of workers, and quality of products. A nonlinear model of the pouring process was built and based on this model, a forward tilting control input was designed to hold the liquid in the sprue cup at a constant level. Furthermore, the backward tilting input was designed by means of the switching control and preshaping method to suppress the slosh after backward tilting and to achieve accurate pour quantity. The effectiveness of the proposed system is shown through control simulation and experiments.

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  Effects of the matrix structure on embrittlement characteristics of ductile cast iron in the aquatic environment were investigated using three kinds of ductile cast iron samples with similar tensile strengths but different microstructures. The samples were obtained by three kinds of heat treatments; quenching and tempering (QT), normalizing (NR), and austempering and sub-zero treatment (ADI-SZ). The embrittlement characteristics were evaluated from the relationship between bending stress and time to fracture, which were obtained from the bending test with HCl solution or ion-exchanged water. ADI-SZ fractured even in the ion-exchanged water after a long period of time under high sustained bending stress, and bending stress decreased markedly in the specimen tested in the HCl solution. This ADI-SZ fractured suddenly without any recognizable creep deflection. The bending stress of NR ductile iron decreased slightly in the HCl solution, but that of QT ductile iron decreased very slightly. Also, tensile strength decreased with hydrogen charge in ADI-SZ. Tensile strength of QT did not decrease with hydrogen charge. These results suggest that the decrease in strength and ductility of ADI-SZ is caused by hydrogen embrittlement. On the other hand, QT ductile iron fractured with some creep deflection, because its sensitivity to hydrogen embrittlement is comparatively low.

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  Magnesium alloy matrix composites reinforced with short alumina fibers and in-situ formed Mg₂Si particles were fabricated by spontaneous infiltration of magnesium alloy to the preform consisting of the fibers and adhered silicon particles. Phosphorus or CaF₂ particles were applied to the in-situ Mg₂Si formation as a refiner. The conditions to finely and homogeneously disperse Mg₂Si particles, formation mechanism and dispersion behavior were investigated. Although the silicon content exceeded its equilibrium solubility in molten magnesium when the silicon volume fraction in the preform was 9.5%, all of the silicon particles changed to Mg₂Si particles after infiltration with molten magnesium alloy. Mg₂Si particles were homogeneously dispersed in the matrix, because the segmentation of Mg₂Si particles in the infiltration was prevented due to the presence of the fibers. As the melting temperature decreased or the cooling rate after the infiltration increased, in-situ formed Mg₂Si particles became finer. Introduction of phosphorus or CaF₂ further refined the in-situ formed Mg₂Si particles.

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