The purpose of this study is to control the series of actions in the pouring process to improve the productivity of factories, the safety of workers, and the quality of products. A mathematical model of the pouring process was built; based on the model, a forward tilting control input was designed to hold the liquid in the sprue cup at a constant level. A pouring flow rate model for the change in the pour rate due to the accumulating slag was constructed, and a learning control system for the automatic pouring robot was developed. The effectiveness of the proposed system is shown through control simulations and experiments.

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  Weldability of dissimilar metal joining of aluminum die casting alloy ADC12 to wrought aluminum alloy A5052 was investigated by using Friction Stir Welding (FSW) at constant tool rotational speed of 1250rpm. Excellent joints were obtained at welding speeds 250 and 500mm/min. At welding speed 750mm/min, cave-like defect generated in the Stir Zone (SZ) of the dissimilar joint. The SZ showed a lamella structure, in which a layer of ADC12 with fine eutectic Si particles and another layer of A5052 with fine recrystallized grains existed alternately like “onion ring”. The hardness of the SZ changed corresponding to the lamella pattern. In the hardness distribution of dissimilar joints, A5052 HAZ softened region showed the lowest hardness. Therefore, the fracture position at the tensile test was the part of A5052 HAZ softened region at welding speeds of 250 and 500mm/min irrespective of the alloy arrangement. The tensile strength of the dissimilar joints at welding speeds of 250 and 500mm/min was about 230MPa, which was 94% of the A5052 base material and 87% of the ADC12 base material at joint efficiency.

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  This paper describes the effects of casting variables on the fluidity of thin wall ZDC 2 (ASTM-AG40A) zinc alloy die casting using a hot chamber die casting machine. The fluidity was evaluated with the filling weight of 70×100mm square test plates of 0.2 to 1.5mm wall thickness. The fluidity was improved by increasing plunger speed. However, complete filling was not achieved with the 0.2mm thickness plate at any plunger speed when a die lubricant diluted 500times with kerosene was used in usual production. A trial for spraying undiluted oil-type die lubricant on a die cavity shows that complete melt filling is possible even if the wall is as thin as 0.2mm. The effect was confirmed by a heat transfer simulation based on the cooling rate which was obtained by measuring the secondary dendrite arm spacing of the specimen when the zinc alloy was gravity-cast in the test mold sprayed with these two different die lubricants. The result shows that the heat transfer coefficient between the melt and die surface clearly decreased by a thick gas film produced by the thermal decomposition of the undiluted die lubricant; thus the fluidity remarkably improved.

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  CO₂ laser beam was applied to the cladding of high carbon high speed steel on alloy tool steel for hot die by a preplaced powder method. The hardness and microstructure of clad layer were investigated by changing the power of laser and number of clad layers. The average hardness of the clad layer was 600 to 700HV0.1 under the following conditions: one layer cladding, laser power of 2400W to 3400W, cladding speed of 400mm/min, defocusing distance of 30mm, oscillation width of 7mm and argon gas shielding. The microstructure of clad layer showed a martensitic and retained austenitic structure because of rapid solidification, and carbides were dispersed in the matrix. A heat affected zone was produced on the surface of the alloy tool steel and a martensitic structure was observed. The clad layer was then heat treated with CO₂ laser beam. The retained austenitic structure of the clad layer transformed into martensite and the hardness of clad layer increased by the heat treatment. EPMA line analysis indicated that an alloyed layer with 20μm in thickness exists between the clad layer and substrated base metal. These results suggest that the CO₂ laser beam cladding of high carbon high speed steel is a useful surface treatment process for alloy tool steel.

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