• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.3
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• pp.251-258
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• 2014

Sunroof tracks are manufactured by press-forming extruded aluminum sheets. During press forming, cracking occurs along the sharply bent edge. The final positions of the punch and die were measured on the section, and their relation to cracking was investigated. Finite element simulation of bending to the final position was done to find the critical strains. Three-point bending tests with different material orientations, hardnesses, bending edge lengths, and bending radii were carried out in the laboratory, and finite element simulation of the three-point bending tests was performed to find the critical strains.

• Journal of Korea Foundry Society
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• v.41 no.3
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• pp.252-259
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• 2021

The magnesium is one of the important alloying elements in the conventional aluminum alloys. The addition of magnesium to aluminum is well known to increase the mechanical strength of the aluminum without the trade-off of the decreased elongation. However, the content of magnesium in aluminum alloys has been limited to be lower than about 5wt.% because of the high oxidation tendency of magnesium element during the manufacturing processes such as casting, hot-forming and post heat-treatments, which can deteriorate the quality and properties of the final products. In this study, new 'ECO-Almag6~9' (containing 6~9wt%Mg) alloys were investigated to be made of the ECO-Mg master alloy, which has been invented to reduce the oxidation tendency of itself. It was successfully demonstrated that ECO-Almag6~9 alloys can be fabricated through the mass-production facilities of DC casting and extrusion routes without the problems of magnesium oxidation. In addition, it was confirmed that the strength and ductility were simultaneously improved due to the addition of high magnesium contents.

• Proceedings of the KSR Conference
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• 2001.10a
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• pp.229-234
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• 2001

The aluminum extruded sections are used to the light construction of the high speed rail vehicle structures. However, the research works on the crashworthy design of aluminum extruded sections are not published sufficiently. In this paper, the collapse characteristics of aluminum extruded sections are investigated by crush test and simulation. The scale model studies are also performed to predict the impact energy absorption characteristics of full scale model through axial crush test and simulation.

• Proceedings of the KSR Conference
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• 1999.11a
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• pp.155-162
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• 1999

Extruded aluminum sections are used to the light construction of the rall vehicles structures However, the research works on the crashworthy design of the extruded aluminum sections are not published sufficiently in this paper, the impact energy absorption characteristics of extruded aluminum sections are investigated by crash simulation and test The optimized energy absorbing studies are also performed based on the selected design parameter variations of the sectional shapes and the dimensional ratios.

• Journal of the Korean Society for Railway
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• v.2 no.2
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• pp.1-5
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• 1999

Based on the development of designed technology for aluminum carbody. the prototype aluminum carbody has been constructed. All extrusion profiles required for the carbody has been produced and their quality has also been proven. For sound construction. welding technology to join aluminum extrusion profiles has been developed and jigs for precise assembly of blocks have been made. The aluminum carbody for urban subway train has been completed with the required chamber being set and the welding deformations being constrained by jigs. The safety of the carbody structure has also been proven by the static load test. And also, painting technology has been developed and the surface of the carbody has been pre-treated and painted. The developed technology to construct the aluminum carbody can be used in mass production of aluminum cars ordered by domestic and foreign customers.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.154-159
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• 2003

In this paper, the design improvement for high speed train carbody, which made by aluminium alloy, was described. The design improvements was achieved in fields of economical efficiency, extrusion, welding, assembling, etc. This paper also describes the result of carbody test. The purpose of the test is to evaluate an safety under the load and operation condition. This strength test based on KTX and reference code is UIC 566 and JIS E 7105. The test results shows that aluminium carbody structural have enough strength for all part.

• Journal of the KSME
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• v.34 no.5
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• pp.342-350
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• 1994

본 연구를 통하여 기존에 사용되고 있던 알루미늄 압출재 블레이드를 복합재료로 대치하여 개 발함으로써 이의 타당성을 검토하여 보았다. 풍력발전기의 개발 추세는 점차 메가와트 (megawatt)급 시스템으로 진행되어 터빈 블레이드가 대형화됨에 따른 터빈브레이드의 경량화 및 내구력의 향상이 절실히 요구된다. 이는 복합소재의 사용으로 경량화를 통한 시스템 각요소의 제작비용절감 및 내구력 향상을 통한 시스템의 수명증대의 효과를 확보할 수 있을 것이다. 그 러나 복합재료를 사용한 터빈 블레이드는 기존의 알루미늄을 이용한 재료보다는 가격경쟁에서 다소 떨어지며 제작공정상의 어려움과 정밀한 설계기술의 미개발 등 아직도 많은 난점을 안고 있는 실정이다. 그러나 현재 풍력에너지 이용 선직국의 개발추이로 보아 대용량시스템의 터빈 블레이드는 복합소재의 사용이 필수적이며 보다 효율적인 양산시스템의 구축과 최적설계에 대한 연구가 지속적으로 실시되면 기존의 블레이드와는 충분한 경쟁성을 확보할 것으로 전망된다.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.10a
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• pp.50-53
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• 2008

It's so difficult to obtain simultaneously both product quality and improvement of the productivity of which products are in hot aluminum extrusion process. But significant improvements in productivity and extrudate quality result from die cooling system using nitrogen gas injection during aluminum hot extrusion. These benefits are due primarily to cooling effect nitrogen gas and removal of excess heat in the extrudate temperature. This investigation is carried out hot extrusion experiment, also compared cooling system with non-cooling system to inspect cooling effects on hot aluminum extrusion. The purpose of this investigation is estimated the grain growth fur the extrudate quality, and the ram speed for the improvement of the productivity.

• Korean Journal of Materials Research
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• v.5 no.8
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• pp.953-959
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• 1995

It was investigated that reinforced species, billet condition and extrusion variation in Al 6061 composite material effected on extrusion process of particulate reinforced composite material. The strength of composite material with reinforcement species revealed SiC$\sub$w/> A1$_2$O$\sub$3f/ > A1$_2$O$\sub$3f/ > A1$_2$O$\sub$3f/ orderly. K$\sub$w/ increased as volute fraction increased in all composite material. The composite materials reinforced by A1$_2$ $O_3$required the larger pressure in hot extrusion process than those by SiC$\sub$p/ at all condition. Extrusion process tended to decrease as the semi-angle of extrusion dies increased because larger contact area caused larger shear friction. Extrusion temperature went up about 50$^{\circ}C$ in low elevated deformation temperature. In extrusion temperature above 500$^{\circ}C$, severe tearing occurred on extrusion surface. More reinforcement in volume fraction, more hot tearing.

• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.103.2-103.2
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• 2012

알루미늄기지 복합재료는 낮은 밀도, 높은 비강도, 우수한 강성을 가지고 있어서 수송기기용 경량소재로서 적용 가능하다. 강화재를 외부에서 주입하는 ex-situ 법에 비하여 화학반응에 의하여 강화상이 생성되는 in-situ 법은 기지와 강화상의 계면 특성이 우수하다. In-situ 주조법으로 제조한 알루미늄기지 복합재료는 여러 형태로 가공하기 위하여 압출, 열간압연 등의 공정을 거치게 되므로 열간가공성에 대한 이해가 필요하다. 이 연구에서는 고온압축시험을 이용하여 in-situ $Al/TiC_p$ 복합재료의 열간가공성을 평가하였다. 고온유동곡선으로부터 변형률속도민감도를 구하였으며 Dynamic Material Model을 이용하여 efficiency of power dissipation을 표현하는 공정지도를 작성하였다. 또한 변형 조건에 따른 미세조직 발달 거동을 조사하였으며 이로부터 각 변형 구간에 대한 변형기구를 도출하였다. 이로부터 알루미늄기지 복합재료의 열간가공성에 미치는 강화상의 영향을 고찰하였다.