• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.10a
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• pp.84-86
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• 2007

Aluminum sheets were asymmetrically cold rolled without lubrication by using different roll velocities of upper and lower rolls in order to intensify the shear deformation. During asymmetrical cold rolling of aluminum sheets, a reduction per a rolling pass, initial sheet thickness, roll diameter, roll velocity ratio were varied to investigate the effect of rolling parameters. The formation of through thickness shear texture was related to the ratio of the contact length between the roll and sample($l_c$) to the sheet thickness(d). The strain states associated with asymmetrical rolling were investigated by the finite element method (FEM) simulation. FEM results indicated that the evolution of deformation texture in a thickness layer is strongly governed by integrated values of strain rates $\dot{\varepsilon}_{13}$ and $\dot{\varepsilon}_{11}$ along the streamline in the roll gap.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.9
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• pp.2142-2153
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• 1995

A digital preview controller using optimal LQ control theory is suggested for tandem cold mills to achieve a remarkable improvement of the thickness accuracy. Optimal preview control system is constructed for each rolling stand of tandem cold mills for which the blocked noninteracting control is carried out, and it is compared with the optimal LQ control system which has only feedback control. And in the cases that all/some of disturbance inputs are previewable, full and partial preview controllers are designed, and their performance effects are compared and discussed. The simulation results show that the performance of tandem cold mills can be improved largely through partial preview control.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.1
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• pp.34-43
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• 1994

In order to improve thickness profile of cold rolled steel strip, a computer simulation and actual cold rolling experiments on a 4-high tandem cold mill were carried out. In this study, tapered barrel end at top work roll and incurved barrel body at bottom work roll were examined for reducing edge drop and threading of stripe. Also, the most effective stand of tandem cold mill and magnitude of optimal taper crown at several stand were investigated under a typical rolling condition. From actual rolling experiments, it was verified that thickness deviation over strip width could be improved up to 1.06% by applying tapered and incurved work roll only at the second and up to 0.89% by applying them at both the second and the third stand.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.05b
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• pp.183-188
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• 1997

핵연료 피복관용 Zr신합금을 개발하기 위해서 16종의 신합금을 설계하였다. 설계된 합금은 진공아크용해, $\beta$-열처리, 열간압연, 냉간압연 및 진공열처리의 공정에 의해 판재로 제조되었으며 이들 시편에 대해 35$0^{\circ}C$와 40$0^{\circ}C$에서 부식시험, 상온과 고온에서 인장시험 및 40$0^{\circ}C$에서 크립시험을 실시하여 신합금의 특성을 평가하였다. Zr-Nb-Sn계에 Fe, V, Te, Sb, Ru, Pd의 다른 원소를 미량 첨가하는 다원계 합금에서 Fe와 Cr은 부식특성을 향상시키는데 매우 효과적인 것으로 나타났다. Sb는 기계적강도를 향상시키고 Fe, Cr원소는 연신율을 증가시키는 원소로 밝혀졌으며 Sb와 V은 크립저항성을 매우 향상시킨다. 16종의 합금중 2-3종의 합금은 기존의 Zircaloy-4보다 우수한 내식성을 보였으며 Zr-Nb-Sn-FeCr합금은 ZIRLO와 유사한 부식저항성을 나타냈다. 부식과 크립저항성을 동시에 향상시키기 위해서는 Fe, Cr, Sb원소를 적절히 함유시킨 합금에 대해서 집중적인 연구가 수행되어야 할 것으로 사료된다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.10a
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• pp.584-585
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• 2010

• Proceedings of the KWS Conference
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• 1999.10a
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• pp.163-166
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• 1999

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.471-472
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• 2009

• Resources Recycling
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• v.9 no.2
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• pp.46-52
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• 2000

Aluminum can to can recycling was divided into two stpes. The first step was composed of the processes such as collection of used beverage cans (UBC), shredding, magnetic separation, De-laquiring, melting and casting. The second one was remelting and casting, heat treating, hot and cold rolling, annealing, and can making. In this study, the effect of alloying elements on the microstructure and texture of the secondary ingots made by Al UBC was investigated. In aluminum can to can recycling, the second phase particles appeared in the solidification stage must be controlled by heat treatment. The optimum heat treatment condition was $615^{\circ}C$ for 5hrs. the texture in hot rolled sheet was depressed with increasing Mn content, on the other hand, Si and Fe elements promoted the texture development. The textures of can-body sheet should be controlled in the hot rolling and annealing stage because can was formed from cold rolled sheet without heat treatment.

• Analytical Science and Technology
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• v.8 no.1
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• pp.85-90
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• 1995

Corrosion characteristics of 4 kinds of the Fe-Al damping alloys has been studied in the 3.5% NaCl solution and compared with a cold rolled mild steel and pure Ti, No passivation, besides Ti, was observed in the Fe-Al damping alloys and a cold rolled mild steel. Corrosion rate was decreased with lower carbon concentration. In the case of Mn addition for improving damping capacity, corrosion rate was decreased in scrap iron but was not decreased in electrolytic iron. It has been shown that corrosion rate of Fe-Al damping alloys lays between that of the pure Ti and that of a cold rolled mild steel.

• Proceedings of the Korean Magnestics Society Conference
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• 2011.06a
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• pp.111-113
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• 2011

변압기, 전동기 등의 에너지 효율을 향상시키기 위해 400 Hz 이상의 주파수에서 사용하는 자성코어 부품의 수요가 증가함에 따라 Si함량이 높은 연자성 코어에 대한 관심이 증가하고 있으며 냉간압연이 어려운 Fe-6.5wt.%Si의 경제적이고 생산성이 높은 분말 성형공정, 주파수에 따른 철손인자들의 영향 및 미세구조 제어에 대한 연구가 체계적이고 지속적 수행되고 있으며 흥미로운 연구결과가 도출되고 있다.