A new method of measuring transferred pressure on metal in die cavity of aluminum die casting was developed and examined on conventional aluminum die casting. In the conventional measurement methods using a knock pin, a steel thin film is put on the tip of the knock pin to protect fin. However, the diaphragm-type pressure gauge is used in the developed method, which dose not require the protection. Furthermore, by applying insulating material film, the transferred pressure in the center of thickness can be measured on the casting surface. The maximum transferred pressure of conventional aluminum die casting decreases in the overflow side of the castings away from gate. Using the new method, the maximum transferred pressure was 90 percent of injection pressure even at the farthest position from the gate. Surface roughness of the die castings decreased with increasing the transferred pressure and molten metal velocity. Internal defects like blowholes diminished with increasing the tranferred pressure.

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  The fluidity of AC4CH alloy is measured using a vacuum fluidity test equipment. The fluidity is evaluated by measuring the flow length before solidification. The movement of flow metal is dynamically recorded by means of a high speed camera (1000 frames per second). Molten metal is drawn into test tubes of quartz and steel under various mold conditions, such as use of paraffin coating or shielding gases. Effects of suction pressure and tube diameter were determined. The fluidity relates linearly to tube diameter and the square root of suction pressure. After correcting for the effects of surface tension and gravity, the fluidity is found proportional to the square root of effective pressure. The fluidity increases slightly by changing mold atmosphere from air to argon. The fluidity is improved by a combined use of coating and argon atmosphere. It was found that the fluidity is twice longer in argon atmosphere than in air when organic coating is applied on the mold surface. From a dynamic observation of flow, flow velocity increases only slightly by mold coating and mold atmosphere, whereas flow life considerably increases by coating and it increases further by a combination of coating and argon gas.

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  Properties of squeeze-cast A6061 aluminum alloy-alumina short fiber composites were examined by the cyclic heat and cool test, and the following results were obtained. Compared with the A6061 aluminum alloy with no addition of fiber and casting composites, extruded composites expand in the direction of fibers arranged with increasing the number of heating and cooling cycle. Conversely, contraction is observed in the transversal direction. The amount of plastic deformation increases when the volume fraction of fiber becomes larger. When composites are heated above the recrystallization temperature, they show a sharp increase in deformation amount because of the void formation, but they show no plastic deformation when they are heated below this temperature. Mechanical properties after cyclic heat test are not affected by the number of heating and cooling cycle. The Young's modulus decreases clearly with increasing the number of cycle, as a result of the increase in internal strain. The internal friction increases with incresing the number of heating and cooling cycle. The increase in internal friction can be attributable to more the effect of void formation around alumina short fibers than the intergranular slip induced by plastic deformation.

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  Successive austempering process (HLAT process) of ADI production proposed by the authors is a new developed heat treatment to improve the toughness of spheroidal graphite cast iron. Both hardenability and austemperability of the iorn are controlled with Mn alloying through the austempering at high and low (2-stage) temperature. Application of HLAT process to the iron produced by Inmold process, which leads to much higher graphite nodule count in the structure than the other spheroidizing methods, was investigated in this study. Higher retained austenite volume fraction and lower untransformed austenite one were obtained in the most suitable duplex upper and lower bainitic structure. It was confirmed that the impact energy of ADI treated by HLAT process was remarkably much higher than the conventional austempering process.

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