• Journal of Korea Foundry Society
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• v.31 no.4
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• pp.205-211
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• 2011

Al-Si alloys have been steadily used as a potential material for the achievement of an efficient weight reduction in the automobile and aerospace industries due to its excellent castability and high strength-to-weight ratio. In this study, riser effect and mechanical properties were investigated according to the size of the sleeve. In addition, the effects of riser size on mechanical properties of castings were investigated. On the other hand flow and solidification process were simulated with a hybrid FDM/FEM package named ZCast. As a result, results of simulation and experiments were comparable regarding to the yield strength, tensile strength, elongation and hardness of casting. It proves the reliability of the simulation. It is expected that the proper size of riser can improve the recycling rate of metallic materials and reduce the cost of casting.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.1
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• pp.314-319
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• 2010

This paper represents the results of study on Extra High Voltage Power Cable Connection System Development. The purpose is to evaluate structural safety by numerical analysis for the relaxation of electric field concentration and by structural analysis of Carrier Pipe for easy installation of High Insulating Rubber Sleeve in the field, which is core technique of connection system. According to the results, the thickness of Carrier Pipe needs at least 9mm by optimization analysis of deformation behavior and insulating design & relaxation of electric field concentration. The result of contraction behavior of the connection part can be demonstrated with the same result of electric field relaxation analysis at the boundary of the electrode inserted into the insulating rubber sleeve.

• Journal of Korea Foundry Society
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• v.24 no.1
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• pp.3-9
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• 2004

Die casting is "a process in which molten metal is injected at high velocity and pressure into a mold(die) cavity". Casting with smooth surfaces, high dimensional precision, complicated shapes, and reduced weight can be obtained using this process. But this process is susceptible to casting defects such as porosities, scattered chilled layers, hard spots, etc. For preventing casting defects, we developed "low-velocity high pressure die casting technology", "squeeze die casting technology", "heat insulating sleeve lubricant technology", and "direct pouring technology". The "direct pouring technology" is useful for producing molten metal without oxide contamination. It consists of a pumping system which supplies pure molten metal to the die casting machine. By using this technology, we have successfully reduced oxide contamination in castings to 1/20 of that of our previous castings.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1216-1217
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• 2008

A description is given of impregnated silicone rubber used in accessories for application on outdoor termination (EB-A). We examines the effects of swelling and mechanical/electrical characteristics for impregnated silicone rubber to develop slip on type sleeve of silicone material. There are semi-conductive silicone rubber and insulation silicone rubber. This examination is monitored as a function of the viscosity and temperature of oil during 30hr. We measure elongation at breakdown and AC breakdown strength and volume resistivities of the oil-impregnated silicone rubbers. The measured values are compared to initial value as function of stress relief cone.