• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.27 no.2
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• pp.125-131
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• 1991

Electrolyte matrix fabrication process can be classifed as hot pressing, tape casting, callendering, electrophoretic deposition. however, these have limits in practice. Hot pressing is cumbersome method, because of careful heating and cooling. Furthermore, the perfected tile is so fragile that it is difficult to fit in a cell. Therefore this method is not adequate for mass production of the electrolyte matrix. Using electrophoretic deposition method, a very thin matrix can be made, but many attempts of the electrolyte embeding were found to be failure. Tape casting and callendering methods are employed in most of the matrix fabrication for the present. But these methods require lots of water as a solvent, so that coating of the LiAlO sub(2) with electrolyte is difficult. Recently, hot roll milling method has been developed and the perfected matrix was proved to be free from crack. The method, however, needs a roller to make a matrix and a perfected matrix is carefully striped off from the cooled roller. Therefore, this method requires a long time due to the cooling process. The author proposes a cold rolling process. On this method, heated slurry of the LiAlO sub(2) mixed with binder, is rolled with a cold roller. The heated slurry dose not adhere to the roller, since contacted hot slurry is rapidly solidified. Therefore fabrication speed is increased, without getting rid of merits of the hot rolling process.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.11
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• pp.97-103
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• 2012

The basic processing unit for instant ramen noodles includes mixing, rolling, boiling, frying, cooling, and packing processes. For uniform thickness of dough sheets in rolling process, the roll-gap in rolling process needs to keep uniform thickness of flour sheets in spite of different kinds of raw materials. In this paper, we have developed a roll gap adjustment system using a PLC (Programmable Logic Controller) with a touch panel and an AC servo-mechanism to make dough sheets with a good gluten starch-network structure and uniform thickness and to contribute to process standardization by transferring from tacit knowledge of skilled workers to explicit knowledge. The developed system can adjust the roll gap in units of 0.01mm and correspond to various product items which have different thickness specification by recalling the presetting values of the desired thickness from database.

• Journal of the Korean Society for Heat Treatment
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• v.6 no.2
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• pp.98-106
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• 1993

Ultra high carbon steel (Fe-1.4%C) was prepared by means of a high frequency induction furnace. The preferred nucleation site of martensite was observed. The changes of hardness and impact thoughness due to tempering temperatures, and the spheroidization of cementite by controlled -rolling were also studied for the steel. The preferred nucleation site of martensite in the ultra high carbon steel is prior austenite grain boundary. The hardness of the steel is slightly increased up to about $300^{\circ}C$, and then decreased with further tempering temperature. However, the impact energy keeps a almost constant value, independent of the tempering temperature. The spheroidization of cementite is accelerated as the reduction in thickness per rolling pass is increased and the number of the rolling passes becomes greater.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1997.03a
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• pp.240-243
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• 1997

The Quenching and Self Tempering (QST) rolling is treated in terms of an advance process on Controlled Rolling and Cooling Technology (CRCT). In the analysis, the effect of this process is governed by both quenching and finishing conditions in the related with temperature. The objective of the QST model is to simulate the temperature gradient of the stock being rolled in the rolling mill. A comparison of computer simulated and manufactured micro structure as well as mechanical properties shows a good consistency. The micro structure of this high-strength round bar consists of tempered martensite and ferrite + pearlite phases.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1072-1075
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• 1996

In hot rolling process at steel plant, cooling of the rolled strip at the exit of the rolling mill is one of the most important processes that would decide the quality of products. To guarantee the thermal equity over the strip, the device called an edge-masking unit is being used. That is installed between the strip and the sprayers to cover the side edge of the strip from spraying water. The accuracy of positioning the bracket is the key to this operation. A machine vision technique can be applied to measure the position of the side edges before an as-rolled strip enters into the cooling facility to rectify the error of preset position of the bracket. This paper shows the simulation result of applying the machine vision technique to measuring the position of a strip and suggests the solution for the target.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1068-1071
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• 1996

Good shape on flat rolled product is necessary to meet today's customer quality requirement. To meet the increasing demand in quality of strip shape from downstream customers, POSCO has replaced the Automatic Shape Control(ASC) system with the existing one that had used noncontact type measuring system at No.2 Cold Rolling Mill, Pohang works in October, 1995. The strip shape is influenced by the profile, roll crown, bending control, skew control system, as well as work roll cooling system. We have used ASC to adjust those factors in Cold Rolling Mill that could get a satisfactory result, almost less than .+-.5 1-unit deviation from the target shape. However, the downstream customer(i.e. Continuos Annealing Line) wants a good shape not only at the moment of exit of roll bite, but after rolling without tension. In this investigation, the difference will be discussed and how deal with this problem.

• Korean Journal of Metals and Materials
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• v.48 no.9
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• pp.798-806
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• 2010

The effects of alloying elements and the cooling condition on the microstructure, tensile properties, and Charpy impact properties of high-strength bainitic steel plates fabricated by a controlled rolling process were investigated in the present study. Eight kinds of steel plates were fabricated by varying C, Cr, and Nb additions under two different cooling rates, and their microstructures and tensile and Charpy impact properties were evaluated. The microstructures present in the steels increased in the order of granular bainite, acicular ferrite, bainitic ferrite, and martensite as the carbon equivalent or cooling rate increased, which resulted in a decrease in the ductility and Charpy absorbed energy. The steels containing a considerable amount of bainitic ferrite or martensite showed very high strengths, together with good ductility and Charpy absorbed energy. In order to achieve the best combination of strength, ductility, and Charpy absorbed energy, granular bainite and acicular ferrite were properly included in the high-strength bainitic steels by controlling the carbon equivalent and cooling rate, while about 50 vol.% of bainitic ferrite or martensite was maintained to maintain the high strength.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.2
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• pp.191-196
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• 2008

This paper proposes a cooling stop temperature control(CSTC) concept which aims at obtaining the uniform temperature and quality of the material along the longitudinal and lateral direction of the strip. The CSTC is designed using the experimental CCT(Continuous Cooling Transformation), TTT(Time Temperature Transformation) curves and the temperature control model by the heat transfer governing equation, and the temperature control simulator. The cooling pattern and the rolling speed can be solved by the CSTC. It is shown through the field test of the hot strip mill of POSCO that the phase transformation ratio of the high carbon steel is considerably improved by the proposed temperature control.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.6
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• pp.1061-1069
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• 1989

본 연구에서는 제조공정을 생략하고, 보다 최종제품의 형상에 가까운 직접압 연법을 실현하기 위한 기초적 연구로서 두개의 회전하는 로울 내부를 냉각하면서 쐐기형 노즐을 통하여 폭이 균일한 용탕을 직접 주입하는 실험방법에 의해서 얻어진 주편의 표면상태와 주조조건과의 관계에 대하여 논하며 또한 기계적성질에 대하여 검토한다.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.94-99
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• 2011

EMU(Electric Multiple Unit) of Seoul Metro are equipped with air conditioning and six line flow fans for air circulation. In summer, the air conditioning and line flow fans usually work at the same time. Recently, high oil price leads more people to use public transportation, which in turn makes them feel hotter inside the rolling stocks and complain about air conditioning state. In order to improve indoor air quality in summer, it is inevitable to increase the cooling capacity of air conditioners, which costs a lot of money. Thus, we need to raise cooling efficiency by rearranging existing devices effectively. In this study, we found a better way to improve refreshment inside the trains by changing the operation method of line flow fans and door opening systems. The results will help improve the cooling efficiency of EMU in summer. Also, more precise experiments and analyses of our data can lead to various methods to increase energy efficiency.