Aging characteristics of AM60B equivalent magnesium alloy cast into iron and copper molds were investigated by means of hardness measurement and microstructure observation with optical microscopy. The microstructure of this alloy in the as cast condition was composed with a primary crystallized alpha magnesium phase and beta phase that was non-equilibrium crystallization in the gap of the alpha magnesium phase. The hardness of the cellular precipitate phase in aged samples was higher from about 5HV to 15HV than the average hardness with increasing aging time. On the other hand, the average hardness of the intragranular precipitate phase was equal to the average hardness against the aging time. Variation of hardness in AM60B equivalent magnesium alloy cast into iron and copper molds with aging at 473K to 523K showed a tendency similar to that in the continuous precipitation area inside the crystal grain.

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  Compacted vermicular graphite cast iron (FCV) has poor machinability than gray cast iron (FC), and thus requires higher machining cost in many cases. For this reason, high speed machining are required for FCV. In this study, it was focused about main factor that reaction wear between cast iron and cutting tool, and oxidation wear of cutting tool in high coefficient machining.
  It was investigated about reaction resistance between FCV, FC and ductile cast iron (FCD) with tool materials, and oxidation resistance of tool materials. The result shows that TiC binder cBN (cBN) was the best reaction resistance, because it was considered that cBN particle didn't react with cast iron materials. Ti(C, N)-Al₂O₃ coated CVD cemented carbide (CVD) had the thickest diffusion thickness. Mg coagulated on the interface of TiN ＋ Ti(C, N) / Al₂O₃ layer in the CVD coating layer in FCV and FCD reaction tests.
  In the oxidation test, CVD had the best oxidation resistance, and cBN the worst. But the microstructure of Al₂O₃ and cBN particle did not change by the oxidation test. The oxidation resistance was found to change according to Ti(C, N) composition and microstructure of each tools.
  It was considered that the oxidation resistance was influenced tool life in FCV high speed machining. These results suggest that high speed FCV machining can be realized for tools made of Al₂O₃ and cBN particles without Ti(C, N) such as Al₂O₃ binder cBN tool.

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  A new type of furan-resin has been developed to improve the working environment and casting quality in foundries. Calcium chloride is added to conventional furan resin, and catalyst containing sulfuric acid is used. The formation of calcium sulfate and hydrochloric acid during the hardening process by the double decomposition between calcium chloride and sulfuric acid is anticipated. Since calcium chloride is sometimes relatively stable and hard to decompose in the temperature ranges of pouring and solidification, significant reduction of sulfurous acid gas is looked forward to. Hydrochloric acid may also additionally work as a superior catalyst for hardening.
  In foundry trials, the newly developed furan resin was able to reduce sulfurous acid gas by about 50% compared with conventional ones during and after pouring heavy cast steel and iron. The hardening time and compressive strength of the molds using the newly developed furan binder were also better than that of conventional ones.

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  An AC4CH aluminum casting alloy was solution-treated using high-frequency induction heating apparatus, and effects of solution treatment on micro-structural features and mechanical properties were investigated. The results were as follows. (1) Investigation of the heated state of the specimen revealed no significant temperature distribution both in the length and width directions of the specimen when the specimen was set at the optimum position in the heating coil. (2) When the AC4CH alloy was solution-treated at temperatures ranging from 450°C to 570°C, under the conditions of heating rate of 40.0°C/s and solution time of 0min, no obvious changes in the size and morphology of the eutectic Si particles were recognized. In contrast, hardness and proof stress increased with rising solution temperature. (3) The aspect ratio of the eutectic Si particles and electrical conductivity of the AC4CH alloy solution-treated at 560°C decreased until the solution time of 3min and then saturated, whereas the size of the eutectic Si particles increased gradually with the lapse of solution treatment time. The hardness and proof stress of these samples increased due to solid solution hardening expected from the change of electrical conductivity. (4) When solution treatment was carried out at heating rates ranging from 0.4°C/s to 40.0°C/s, there were no changes in the electrical conductivity, hardness, and proof stress. However, growth of the eutectic Si particles was suppressed at the heating rate of 40.0°C/s.

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