• Journal of Mechanical Science and Technology
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• 제16권10호
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• pp.1296-1302
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• 2002

A mathematical model for cold rolling and temper rolling process of thin steel strip has been developed using the influence function method. By solving the equations describing roll gap phenomena in a unique procedure and considering more influence factors, the model offers significant improvements in accuracy, robustness and generality of the solution for the thin strip cold and temper rolling conditions. The relationship between the shape of the roll profile and the roll force is also discussed. Calculation results show that any change increasing the roll force may result in or enlarge the central flat region in the deformation zone. Applied to the temper rolling process, the model can well predict not only the rolling load but also the large forward slip. Therefore, the measured forward slip, together with the measured roll force, was used to calibrate the model. The model was installed in tile setup computer of a temper rolling mill to make parallel setup calculations. The calculation results show good agreement with the measured data and the validity and precision of the model are proven.

• 소성∙가공
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• 제11권1호
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• pp.24-35
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• 2002

Recent trend and future prospect of flat rolling of steel has been summarized based on the earlier reports. Key technology in the plate rolling is to have ultra fine microstructure having high resistance against crack propagation during application. Heavy accelerated cooling facility and high power rolling mill will be helpful to develope the high toughness steel. Precise modeling of properly prediction based on deformation and transformation imposed on microstructure of steel during processing is highly anticipated. For the hot strip rolling process, new trend is lies on the production of ultra-thin gauged hot strip to substitute cold rolled strip. For the substitution of cold rolled strip into hot rolled strip widely, high formable property of hot strip is highly required. For the formabilit, the ferritic rolling of extra low carbon steel under high lubricated condition is essential. Recently introduced semi-continuous thin slab and rolling mill line is very plausible to develope those kinds of products easily In the view groin facility combination. New idea to modify the existing continuous hot strip mill line to produce the ultra thin-gauged hot strip in an economic way is suggested in this report.

• 한국정밀공학회지
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• 제25권11호
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• pp.66-72
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• 2008

During the plate and foil cold rolling process, considerable values of the force of material pressure on the tool occur. These pressures cause the elastic deformation of the roll, thus changing the shape of the deformation legion. Rolled copper foils should be characterized by a good quality and light dimensional tolerances. Because of automation that is commonly implemented in flat product rolling mills, these products should meet the requirements of tightened tolerances, particularly strip thickness, and feature the greatest possible flatness. The shape of the roll gap is influenced by the elastic deformation of rolls parts of the rolling process affecter of the pressure force. However, to control roll deformation should be difficult. Because the foil thickness is very thin and the permissible deviations in the thickness of foil are small. In this paper, FE-simulation of roll deformation in thin foil cold roiling process is presented.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2007년도 춘계학술대회 논문집
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• pp.413-416
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• 2007

In general, by means of the electrodepositing technique, a copper foil sample was prepared with a high purity and a high density. But the mechanical properties of the electrodepositing copper foil was lower than it's the rolling copper foil. However, the production of copper foil with approximately 36 microns thick in rolling process was very difficult. This paper describes the outline of the high accuracy cold rolling in 6 high mill which was developed for the purpose of rolling very thin accurate gauge copper foil(36 micron thick), and give several rolling characteristic of 600 mm wide copper foil. a) Large strain can be accumulated pass by pass in industrial multi-pass rolling processing to overcome large critical strain for thickness accuracy through optimization of rolling schedule. b) Also, permissible tension for rolling 0.45 $\sim$ 0.036 mm thick copper strip stably in accordance with the each pass work had been established by FEM simulation results. c) During the plate rolling process, considerable values of the forces of material pressure on the tool occur. These pressures cause the elastic deformation of the roll, thus changing the shape of the deformation region. A numerical simulation of roll deflection during cold rolling is presented in the paper. d) The proposed pass schedule can roll very thin copper foil of 36 micron thickness to a tolerance of ${\pm}1$ microns. The validity of simulated results was verified into rolling experiments on the copper foil.

• 소성∙가공
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• 제12권2호
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• pp.123-127
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• 2003

The cold rolling conditions for the ultra thin steel for tension mask are very important because the residual stress that affects the flatness of strip is generate during the cold rolling. The residual stress in the sheet causes etching curls when it suffers perforation process. The residual stress through the thickness. To estimate the residual stress and deformation due to etching curl. FEM analysis is performed. Numerical simulation employ a ANSY5 5.6 and an elastic-plastic constitutive equation. The simulation results indicate the distribution of residual stress in the rolled sheet can be controlled by selecting the rolling conditions properly.

• 대한기계학회논문집A
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• 제35권8호
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• pp.855-861
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• 2011

본 연구에서는 극박 압연 이론과 6 단 압연기 수식 모델을 이용하여 압연 후 판 형상 예측에 대하여 제안하였다. 폭 방향에서 롤 사이의 접촉 압력과 판과 워크롤 사이의 압연하중은 6 단 압연기의 형상학적 구조와 경계조건을 이용한 수식모델을 통하여 계산된다. 그리고 압연 방향의 압연하중 분포는 Fleck 의 극박 압연 이론을 이용하여 계산하였다. 워크롤의 3 차원 탄성 변형량은 폭 과 압연방향의 압력분포에 의하여 계산된다. 이때, 3 차원 판 형상은 워크롤의 탄성변형에 의하여 얻어진다. 또한 3 차원 판 형상은 극박 압연 실험과 유한요소해석을 통하여 검증하였다.

• 한국정밀공학회지
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• 제13권3호
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• pp.49-55
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• 1996

Recently, the necessity for more accurate automatic gauge control has increased of customers' requirement for cold rolled steel sheets with thinner gauge and better gauge quality. Therefore, many cold rolling mills replaced its electric screw down automatic gauge control system with a new hydraulic automatic gauge control system, to ensure closer gauge tolerance. In this paper, The performance of a hydraulic automatic gauge control system for cold rolling has been investigated under industrial conditions. It was investigated that variation of gauge deviation according to the final products thickness, cold rolling speed and pass number, in the actual rolling mill. As a result, it was found that the system enables strip thickness variation to be reduced substantially and caused by poor gauge deviation have been drastically decreased. The test results are as following. The more the exit steel strip thickness is thick, the smaller the aguge deviation rate is large, and the more it is thin, the large the gauge deviation rate is large. Because the gauge deviation is larger at accleration speed and deceleration speed than steady speed, so automatic gauge control system is better to adopt over 50m/min. automatic gauge control system reduces rapidly large thickness deviation.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1999년도 제3회 압연심포지엄 논문집 압연기술의 미래개척 (Exploitation of Future Rolling Technologies)
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• pp.132-141
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• 1999

No. 1 PL(Pickling Line) and No. 1 TCM(Tandem Cold Rolling Mill) at Pohang works started up in 1977 and have been operating successfully keeping high productivity for productivity thin gauge sheat such as BP, CR and silicon steel. On the other hand, customer's requirements of quality level are rasing higher continuously, so that Pohang works has combined and revamped No. 1 PL and No. 1 TCM in order to improve labor productivity, thickness accuracy and shape control capability, and so on in the period of 1977∼1999. This paper introduce the applied facilities, technologies and recent operations after revamping.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1999년도 제3회 압연심포지엄 논문집 압연기술의 미래개척 (Exploitation of Future Rolling Technologies)
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• pp.142-149
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• 1999

Strip profile and shape control is one of the most important technologies in cold mill, especially for ultra-thin and wide cold strip. The 6-high mills, both of HCMW and UCMW mill, are known to be very effective for the shape controllability. The optimized values of these factors for set-up scheduling were analyzed and found that excellent strip control would be possible by controlling the combination of the influencing factors according to hot coil profile. The important considerations for operation were discussed for individual stand.

• 한국재료학회:학술대회논문집
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• 한국재료학회 1998년도 IUMRS-ICEM ABSTRACT BOOK
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• pp.51.2-51
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• 1998