• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.3
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• pp.285-295
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• 2001

The transport phenomena in a wedge-shaped pool of twin-roll continuous caster are affected by the various operating parameters such as the melt-feed pattern, roll-gap thickness, melt-superheat, and casting speed. A computer program has been developed for analyzing the two-dimensional, steady conservation equations for transport phenomena during twin-roll continuous casting process in order to estimate the turbulent melt-flow, temperature fields, and solidification in the wedge-shaped pool. The turbulent characteristics of the melt-flow were considered using a low-Reynolds-number K-$\xi$ turbulence model. Based on the computer program, the effects of the different melt-feed patterns, roll-gap thicknesses, and superheats of melt on the variations of the velocity and temperature distributions, and the mushy solidification were examined. The results show that the liquidus line is located considerably at the upstream region, and in the lower region appear the well-mixed melt-flow and most widely developed mushy zone. Besides, the variation of melt-flow due to varying melt-feed patterns, affects mainly the liquidus line, and scarcely has effects on the solidus line in the outlet region.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.11
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• pp.1309-1315
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• 2011

The design process for obtaining the reliable steeraxle casting beam of fork lift truck is studied in this paper, as the casting beam is major component of steeraxle which has a steering function at driving. In this study, the driving mode and damage pattern of casting beam which could be occurred from the customer site were analyzed and it established the design process to predict the fatigue life by FEA(Finite Element Analysis) so that the reliability of steeraxle casting beam could be verified at DVT(Design Validation Test) mode. This paper provides guidance on the process of designing the reliable steeraxle casting beam at the initial design stage and also, provides guidance on the process of solving the problem when the failure is occurred in the field.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.3
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• pp.45-53
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• 2009

Die casting process of Mg alloys for high temperature applications was studied to produce an engine oil pan. The aim of this paper is to evaluate die casting processes of the Aluminium oil pan and in parallel to apply new Mg alloy for die casting the oil pan. Temperature distributions of the die and flow pattern of the alloys in cavity were simulated to diecast a new Mg alloy by the flow simulation software. Dies have to be modified according to material characteristics because melting temperature and heat capacity are different. We changed the shape and position of runner, gate, vent hole and overflow by the simulation results. After several trial and error, oil pans of AE44 and MRI153M Mg alloys are produced successfully without defect. Sleeve filling ratio, cavity filling time and shot speed of die casting machine are important parameter to minimize the defect for die casting Magnesium alloy.

• Journal of Technologic Dentistry
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• v.6 no.1
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• pp.19-26
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• 1984

This Experimental study was performed to study the effect of the heat soaking and the diameter of pattern on the casting ability of three nonprecious alloys manufactured for porcelain-metal restorations, with respect to their ability to reproduce test pieces by casting over a selected range of uniform diameters. Samples of total 60 were constructed and divided into 6 groups according to the two variables, the diameter and the heat soaking. The completed cast samples were examined visually and measured with a caliper calibrated to 0.05mm. The results obtained were as follows: 1. Length cast was significantly related to the diameter to be cast, especially in the case of the marrowest diameter of 230m. 2. Length cast not significantly related to the heat soaking. 3. The completeness of casting was significantly related to the diameter to be cast, particularly in the case of the narrowest diameter of 230m. 4. The completeness of casting was not significantly related to the heat soaking. 5. All of the three nonprecious alloys used for this experiment were significantly different from an ideal alloy in the completeness of casting.

• Korean Journal of Materials Research
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• v.16 no.11
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• pp.668-675
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• 2006

In the partial squeeze casting process, the filling behavior of liquid metal and solidification pattern in thick area have significant influence on the quality of casting products and die life. For the optimal casting design of automobile transmission gear housing, various analyses were performed in this study by using computer simulation code, MAGMAsoft and the simulation results were compared and analyzed with experimental results. By air pressure criteria, internal porosities caused by air entrap during the mold filling were predicted and reduced remarkably by modification of gating system. Also, optimal squeeze-time lag to apply partial squeeze pin in thick area was calculated and the castings was free from shrinkage defects with the result of solidification analysis. Consequently, casting design for automobile transmission gear housing was optimized and approved by Computer Tomography.

• Journal of the Korean Ceramic Society
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• v.30 no.10
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• pp.845-851
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• 1993

Low firing temperature substrate were synthesized through tape casting and sintering of glass with cordierite composition and then their properties were investigated. Even though the dielectric properties and XRD patterns of substrates, obtained by tape casting and sintering at 900~100$0^{\circ}C$ for various periods, were similar to those of substrates obtained by dry pressing, the sinterability was enhanced. The substrates were thin and the size was 0.6$\times$50$\times$50mm. From the results of dielectric properties, the sinterability and X-ray diffraction pattern, the proper condition for cofiring process with conductor, Cu, was 90$0^{\circ}C$ for 1h. The properties of the substrate are as follows; the dielectric constant was 5.31(at 1MHz), the dissipation factor was 0.0028, the apparent porosity was 0.28% and the main crystalline phase was $\alpha$-cordierite.

• Journal of Korea Foundry Society
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• v.25 no.5
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• pp.190-194
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• 2005

• Journal of Korea Foundry Society
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• v.9 no.4
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• pp.301-304
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• 1989

• Journal of Korea Foundry Society
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• v.14 no.1
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• pp.13-18
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• 1994

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.32 no.1
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• pp.25-32
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• 2022

Investment casting is a production method commonly used to manufacture precision equipment, medical fields, and accessories, and has continued to develop through the modernization of equipment and high quality of materials, and its scope of use has been expanded. The purpose of this study is to minimize the defect rate by deriving structural improvement and standardization of mold temperature, which are key elements of the investment casting process, to minimize the defect rate. The scope of the study is limited to jewelry manufacturing casting processes suitable for understanding the structure and principles of small gate, and an experimental research is to be conducted by using soft Wax, gypsum powder, and 14 K gold as research materials. According to the results, the most appropriate casting standard temperature for the casting pattern of Alloy 14 k was the lowest turbulence at 980℃ flask temperature of 550℃, so good products could be produced. As a future task of this study, detailed studies are needed to data the structure and system temperature of small gate, reduce production defects in the field, and provide data for excellent investment casting competitiveness.