• Journal of Korea Foundry Society
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• v.40 no.6
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• pp.135-145
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• 2020

Aluminum cast iron has excellent oxidation resistance, sulfurization resistance, and corrosion resistance. However, the ductility at room temperature is insufficient, and at temperatures above 600?, the strength drops sharply and practicality is limited. In the case of heat-resistant cast iron, high-temperature materials containing Cr and Ni account for 30 to 50% or more. However, these high-temperature materials are expensive. Aluminum heat-resistant cast iron is considered as a substitute for expensive heat-resistant materials. Oxidation due to the aging temperature and holding time conditions increases more in 0 wt.% Al-cast iron than in 2 and 4 wt.% Al-cast iron according to oxidized weight and gravimetric oxide layer thickness measurements. As a result of observing the cross-section of the oxide layer, it was found to contain 0 wt.% of Al-cast iron silicon oxide-containing SiO₂ or Fe₂SiO₄ oxide film. In cast iron containing aluminum, the thickness of the internal oxide layer due to aluminum increases as the aging temperature and retention time increase, and the amount of the iron oxide layer generated on the surface decreases.

• Journal of Korea Foundry Society
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• v.26 no.3
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• pp.123-128
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• 2006

Mechanical and thermal properties of spray-cast hypereutectic Al-20wt.%Si-xwt.%Fe alloys (x=0, 1, 3, 5) were investigated. After the spray-casting, hot extrusion was performed at $400^{\circ}C$. Intermetallic compound (${\beta}-Al_5FeSi$) and primary Si are observed in the spray-cast aluminum alloys. The size of primary Si and intermetallic compound of the spray-aluminum alloys became finer and more uniformly distributed than that of the permanent mold cast ones. Ultimate tensile strength of the spray-cast aluminum alloys increased by increasing Fe contents, but that of the permanent mold cast aluminum alloys decreased by increasing Fe contents possibly due to increased amount of coarse intermatallic compound. The coefficient of thermal expansion (CTEs) of the aluminum alloys became lower with finer primary Si and intermetallic compound, and this is attributed to the increased amount of interfacial area between the aluminum matrix and the phases of finer Si and intermetallic compound.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.6
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• pp.60-68
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• 2013

The present research aims to develop aluminum disc brakes to replace existing cast iron disc brakes in automobiles. The foundation for developing an aluminum disc is laid by investigating the performance characteristics of existing cast iron disc brakes and comparing those characteristics with those of aluminum disc brakes. This study involves FEM thermal/structural analysis of disc materials and experimental tests using a brake dynamometer. The results of this study show that, aluminum discs have not only better thermal/mechanical properties than existing cast iron discs, including better heat, wear, and crack resistance, but also that aluminum discs. Weigh less than existing cast iron discs, which results in improved maneuverability. Aluminum discs will become a more essential part of automobiles as electric cars become the major means of transportation.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.905-909
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• 2001

The significance of casting/forging process for reducing the production cost of large components is being noted in these days. This casting/forging process is a method of forging a workpiece preformed by casting into the final shape. In this study, the casting/forging process has been applied in manufacturing a large aluminum flange in order to determine the optimum forging condition of the aluminum flange. The optimum range of forging temperature of Al 5083 was from $420^{\circ}C$ to $450^{\circ}C$. The suitable strain rate was 1.5 $sec^{-1}$. The deformation amount of a preform in a forging process is key role in the mechanical properties of casting/forging products. In order to find the change of mechanical properties according to effective stain of cast aluminum billets, a hot upsetting test were performed with rectangular blocks and then a uniaxial tensile test was performed with specimens cut from the upsetted billets. The tensile strength and the elongation of cast/upsetted aluminum billets were increased largely until the effective strain was 0.7. FE analysis was performed to determine the configurations of cast preform and die for an aluminum flange. In the FE analysis, the forging load-limit was fixed 1500ton for the low equipment cost. The cast preform was designed so that the effective stain around the neck of a flange exceeds 0.7. In the forging experiment for an aluminum flange, it was confirmed that the optimal configuration of the cast preform predicted by FE analysis was very useful. The cast/forged products using designed preform were made perfectly without any defects.

• Journal of Ocean Engineering and Technology
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• v.17 no.5 s.54
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• pp.76-81
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• 2003

Friction welding of GCD45 spheroidal graphite cast iron and 2024 aluminum alloy has been studied, especially in terms of the joint faces and strength of friction welding. For appropriate results of the friction welding of GCD45 graphite cast iron and 2024 aluminum alloy, an insert of A1050 pure aluminum metal was used. The joint strength of the A1050 pure aluminum insert approached the maximum strength of 165.7Mpa, compared to 128MPa for the joint between GCD45 graphite cast iron and A1050 pure aluminum without the insert metal. Maximum strength, 165.7Mpa, was possible for the following optimum conditions: 20MPa for the friction pressure, P1, 60MPa for the upsetting pressure, P2, 1 second for the friction time, t1, 3000rpm for the rotation, N, and 0.3 seconds for the brake time, tB.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.25 no.2
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• pp.138-142
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• 2016

In this study, a strength analysis was performed to assess die-cast aluminum alloy brake pedals as an improved alternative to wrought alloys. Aluminum brake pedal shapes are considered to be suitable for the die-casting process. The strength criterion of Volvo trucks was used as the criterion for the pedal strength. The results of this analysis showed that the frame thickness of the aluminum brake pedal must be increased from 12 mm to 18 mm to have a strength superior to that of a steel brake pedal. Additionally, the stress and weight of the aluminum brake pedal were found to be approximately 24% and 26% lower than those of the steel brake pedal, respectively. Mounting tests and strength assessments verified that the proposed die-cast aluminum alloy brake pedal demonstrated sufficient strength.

• Journal of the Korean institute of surface engineering
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• v.20 no.4
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• pp.144-153
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• 1987

In the case of dipping the Ni-Resist cast iron into molten aluminum with iron content, the thickness of intermetallic compound was remarkably increased with increasing iron content. The thickness was shown by following equation in the range of 1-3% iron content; $x=22.5t^{1/2}+4.47{\cdot}t{\cdot}(Fe%)$. where, x is thickness(${\mu}m$), t the time (minute), Fe% the iron w/o. When the Ni-Resist cast iron was dipped into the molten aluminum containing zinc content, the intermetallic compound thickness was also increased with increasing zinc contents. And thickness was represented by the following equation in the range of 2-10% zinc content; $x=3.46t^{1/2}+0.27{\cdot}t{\cdot}(Zn%)$. However, in the case of dipping the Ni-resist cast iron into molten aluminum with silicon content, the thickness of intermetallic compound was decreased with increasing silicon content, as shown in the following equation; $x=7.17t^{1/2}-0.15{\cdot}t{\cdot}(Si%)$. The intermetallic compound formed onto Ni-Resist cast iron was identified to be $FeAl_3\;and\;Fe_3Al$. As the result of hardness measurement, the peak hardness appeared in the intermetallic compound at near interface of the cast iron and the compound.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.1
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• pp.180-185
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• 2002

Aluminum casting/forging process is used to produce an aluminum tie-rod end for the steering system of automobiles. Firstly, casting experiments were carried out to get a good preform for forging the tie-rod end. In the casting experiment, the effects of additives, Ti+B, Zr, Sr, and Mg, on the mechanical properties and the microstructure of a cast preform were investigated. And a finite element analysis was performed to determine an optimal configuration of the cast preform. Lastly, a forging experiment was carried out to make the final product of aluminum tie-rod end by using the above cast preform. In the casting experiments, when 0.2% Ti+B and 0.25% Zr were simultaneously added into molten Al-Si alloy, the highest values of tensile strength and elongation of the cast preform were obtained. When 0.04% Sr were added into the molten aluminum alloy, the finest silicon-structure was observed in the cast preform. The highest hardness was obtained when 0.2% Mg was added. In the forging experiment, It was confirmed that the optimal configuration of a cast preform predicted by FE analysis was very useful. The hardness of a cast/forged product using designed preform was superior to that of required specification.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.9
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• pp.1438-1443
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• 2001

The significance of the casting/forging process for reducing the production cost of large components is being noted in these days. This casting/forging process is a method of forging a workpiece preformed by casting into the final shape. In this study, the casting/forging process has been applied in manufacturing a large aluminum flange in order to reduce press capacity and material cost. Firstly, a hot compression test was performed with cast cylindrical billets in order to determine the optimum forging condition of the aluminum flange. The optimum range of forging temperature of Al 5083 was from 420$\^{C}$ to 450$\^{C}$. The suitable strain rate was 1.5 sec(sup)-1. The deformation amount of a preform of a preform in a forging process is a key role in the mechanical properties of casting/forging products. In order to find the change of mechanical properties according to effective stain of cast aluminum billets, a hot upsetting test were performed with rectangular blocks and then a uniaxial tensile test was performed with specimens cut from the upsetted billets. The tensile strength and the elongation of cast/upsetted aluminum billets were increased largely until the effective strain was 0.7. FE analysis was performed to determine the configurations of case preform and die for an aluminum flange. In the FE analysis, the forging load-limit was fixed 1500ton for low equipment cost. The cast preform was designed so that the effective stain around the neck of a flange exceeded 0.7. From the result of FE analysis, optimal configurations of the cast preform and the die were designed for a large flange. The filling and solidification analysis for a sound cast-preform was carried out with MAGMA soft. In the forging experiment for an aluminum flange, it was confirmed that the optimal configuration of the cast preform predicted by FE analysis was very useful. The cast/forged products using designed preform were made perfectly without any defects.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.9
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• pp.30-36
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• 1997

In this study, the development of an aluminum forged piston was tried to substitute the cast piston, in which there were internal defects such as blow hole and shrink pipe. A gasoline engine piston was chosen as an example for developing the forged piston. Before aluminum forging, model, material (plasticine) test was carried out to investigate the forgeability and internal flow pattern of the forged piston at room temperature. From the result of model material test, an aluminum piston to be forged was redesigned. The aluminum pistion was forged in hot process. The quality of a forged piston was compared with that of a cast piston in the point of mechanical properties, internal defect and microstructure. It was proved that the forged piston was superior to the cast piston.