• Transactions of Materials Processing
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• v.28 no.5
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• pp.247-256
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• 2019

In this study, the development of annealing textures in cold rolled and annealed tantalum sheets was analyzed using electron backscatter diffraction. At $900^{\circ}C$, the textures of the recrystallized grains in the partially and completely recrystallized microstructures displayed significant similarities. The average diameter of the recrystallized grains with ${\gamma}-fiber$ orientations exceeded that of grains with different orientations, and the average growth rates were unrelated to the orientations after an initial stage of recrystallization. Additional cold rolling and annealing was done for controlled initial microstructures and textures inherited from various processes of prior cold rolling and annealing. This second cycle of the process resulted in stronger textures with major ${\gamma}-fiber$ orientations as a result of the enhanced ${\gamma}-fiber$ orientations in the preceding textures. A coarse-grained prior microstructure resulted in a weaker annealing texture than a fine grained one regardless of the stronger previous texture, which was occasioned by the sub-structures of the minor orientations at local deformation inhomogeneities such as sharp in-grain shear bands.

• Progress in Superconductivity and Cryogenics
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• v.8 no.1
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• pp.19-22
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• 2006

Desirable substrates for $YBa_2Cu_3O_{7-\delta}$ coated conductor are highly cube textured Ni or Ni-alloy tapes, which can be produced by cold rolling and recrystallization annealing. We have fabricated hi-axially textured pure Ni tapes for the application of coated conductors. The sintered Ni rod was cold-rolled into the thin tapes of $50{\mu}m$ thickness and the tapes were heat-treated for texture development with line-focused infrared heater. The temperature was maintained at $800\sim1050^{\circ}C$, using 1kW double ended linear halogen lamp in $96%Ar-4%H_2$ atmosphere The biaxially tortured Ni tapes were successfully formed by line-focused infrared heat treatment The texture of the annealed Ni tapes was analysed using the GADDS (general area detector diffraction system). The full width at half maximum values of phi and omega scan for the Ni tapes were less than $10^{\circ}$ and the grain size was $20-50{\mu}m$.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.5
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• pp.67-73
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• 1996

The necessity for more accurate automatic flatness control(AFC) system has increased of customers' requirement for cold rolled steel sheet. Therefore, many cold rolling mills replaced its AFC system with a measuring roll of the contact type form the non-contact type. In this paper. The performance of AFC system of contact type has been investigated under industrial conditions. It has two kinds of actuator: roll bender, spot cooling system. The test results are as follows: The more strip thickness is thick, the smaller the I value, and the more it is thin, the bigger the I value. And a complex distribution of strip tension was controlled, for example, not only a pocket wave but also a simple center wave and edge wave. Because the tension deviation is larger at acceler- ation speed and decelerationspeed than steady speed, AFC system of contact type is better to adopt over 50m/mim. AFC system reduces rapidly large flatness deviation. The maximum I value of strip has been decreased to 13 I, and sticker, defects caused by poor flatness, have been decreased about 60%.

• Tribology and Lubricants
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• v.5 no.2
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• pp.21-31
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• 1989

최근 국내에서도 각종 공작기계 가공의 발전으로 말미암아 이에 쓰여지고 있는 윤활제의 이용범위도 점진적으로 확대되어 가고 있음은 물론 특히 Water계 윤활제의 요구성능은 점점 가혹하게 되어지고 있다. Water계 윤활제라고 하면 일반적으로 Cutting, Grinding, Drawing, Pressing, Heat Treating 등의 공작기계 계통의 Oil을 연상할 수 있겠지만 이들 이외에 각종 유압작동유를 비롯하여 Rolling Oil도 포함되고 있다. 따라서 본 논고에서는 근간 Crose up 되어지고 있는 Water계 윤활제 중 냉각압연유에 대하여 간략하게 기술하여 보고자 한다.

• Transactions of Materials Processing
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• v.10 no.2
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• pp.160-166
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• 2001

Uniaxial necking is studied for steel sheets with initial anisotropy. The state of anisotropy is continuously altered by subsequent tensile deformation at angles to the rolling direction. The orientations of orthotropy axes are changed before the onset of necking. A simple hardening rule which incorporates the rotations of orthtropy axes is proposed and the necking strains are predicted at angles to the rolling direction. Predicted results show good agreement with the experiments.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1997.10a
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• pp.153-157
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• 1997

The investigation deals with the process design in cold rolling mill of electric plant. In this study, multiple objective optimization is conducted by a genetic algorithm, where the fitness values are evaluated on the basis of one - dimensional model of flat rolling. The approach is applied to the determination of the process conditions which are optimal with regard to minimization of roll power and maximization of productivity.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.10a
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• pp.328-329
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• 2007

A study on the texture and the formability after frictional rolled and subsequent heat-treated AA 1050 aluminum alloy sheets have been carried out. The specimens after the frictional rolling showed a very fine grain size, a decrease of <100>//ND, and an increase of <111>//ND textures. The change of plastic strain ratios has been investigated and it was found that they were higher than those of the initial Al sheet.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.10a
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• pp.332-333
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• 2007

The effect of asymmetric rolling on the recrystallization texture of an AA 3003 Aluminum alloy was investigated by X-ray diffraction. It was found that the texture of asymmetrically rolled sheets prior to subsequent heat treatment promoted the formation of the <111>//ND textures, and remained after heat treatment at $275^{\circ}C$ during 20 min in salt bath condition.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.05a
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• pp.480-481
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• 2008

The aim of this work is to compare the microstructure, the texture, of an AZ31 Mg alloy processed via cold rolling process. Initial AZ31 Mg alloy sheet samples with strong {0002} texture were cut along the angles of 12.5 and 25 degrees to normal direction (ND). These specimens were rolled in room temperature condition. The microstructure was characterized by optical microscopy and the texture was measured by X-ray diffraction.

• Journal of the Korean Society for Heat Treatment
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• v.11 no.3
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• pp.192-199
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• 1998

This study was carried out to investigate the influence of variations in the temperature and time of isothermal heat treatment, applied stresses and prestrain on the isothermal transformation behavior of ${\gamma}$ and ${\sigma}$ phases and mechanical properties of 25Cr-7Ni-3Mo duplex stainless steel. The precipitation of ${\gamma}$ and ${\sigma}$ phases through isothermal heat treatment showed the type curves with a certain incubation period, the curve migrated to in a short period of time and the amount of precipitation increased with decreasing isothermal heat treatment temperature. Under the state of isothermal transformation, the precipitation of ${\gamma}$ and ${\sigma}$ phases was stimulated by applied stress, with increasing applied stress, the curves migrated to in a short period of time and also observed that the application of stress has a greater influence on the amount of ${\sigma}$ precipitation than that of ${\gamma}$ precipitation. The precipitation of ${\gamma}$ and ${\sigma}$ phases was stimulated by cold and warm rolling before isothermal heat treatment and precipitation of ${\gamma}$ and ${\sigma}$ phases has a greater influence on the warm rolling than cold rolling. The tensile strength and hardness increased with increasing cold and warm rooling reduction ratio.