• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 춘계학술대회 논문집
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• pp.70-73
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• 2004

The approach in this thesis is for prediction of deformed strip profile in hot rolling mill. This approach shows how to make an expression as a mathematical form in predicting strip profile. This approach is based on the velocity field, shear stress and material flow on the strip edge along width direction and lateral displacement and stress along width are analytically calculated. Roll force is calculated in each section and then combined together to show roll force distribution along width. All the assumptions to make equation form for this approach are supported by FEM simulation result and the result of model is verified by FEM result. So, this model will supply very useful tool to the researcher and engineers which takes less time and has similar accuracy in predicting roll force profile comparing to FEM simulation. This model has to be combined with deformed roll profile model, which include thermal crown prediction and wear prediction model to predict deformed strip profile.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.1083-1086
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• 1996

Cold rolling mill process in steel works uses stands of rolls to flatten a strip to a desired thickness. At cold rolling mill process, precalculation determines the mill settings before a strip actually enters the mill and is done by an outdated mathematical model. A corrective neural network model is proposed to improve the accuracy of the roll force prediction. Additional variables to be fed to the network include the chemical composition of the coil, its coiling temperature and the aggregated amount of processed strips of each roll. The network was trained using a standard backpropagation with 4,944 process data collected from no.1 cold rolling mill process from March 1995 through December 1995, then was tested on the unseen 1,586 data from Jan 1996 through April 1996. The combined model reduced the prediction error by 32.8% on average.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 전력전자학술대회 논문집
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• pp.715-718
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• 2002

As the modern technology of continuous casting plant is focused on improvement of slab quality, the control system of strand driven roll which has positive effect is investigated in this paper. An irregular distribution of withdrawal force gives rise to horizontal crack in high and middle grade carbon steel. Based on the basic understanding on design concept of high technology company, monitoring the withdrawal force distribution of strand driven roll and analysis of the control system was Performed at continuous casters of POSCO. The control algorithm of withdrawal force distribution for A.C motor vector control, which was derived from above study and had been applied for POSCO Kwangyang 1-4 continuous casting plant, is presented.

• 소성∙가공
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• 제19권6호
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• pp.344-351
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• 2010

This paper presents a precision on-line model for the prediction of the roll force and tension distributions across the strip in hot strip rolling. The approach is based on an approximate 3-D theory of rolling, and in particular, considers the effect of pre-deformation of the strip, which occurs near the roll entrance before the strip enters the bite zone. The prediction accuracy of the proposed model is examined through comparison with the predictions from the 3-D finite element models.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.761-764
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• 2005

In this paper, multi-pass roll forming process is simulated with a commercial FEM software. From these simulations, detects like excessive thickness decrease were estimated. And effects of springback, idle roll without force, and self-contacts between materials were also predicted. As a result, the defects of the forming process and the numbers of the roll pass can be decreased. And these analyses will be able to design the optimal roll forming process.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2008년도 추계학술대회 논문집
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• pp.729-730
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• 2008

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 추계학술대회 논문집
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• pp.286-287
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• 2008

The determination of roll speeds in continuous rolling system is an important factor along with the design of roll profile and roll gap. The tensile force on the workpiece induces reduced cross section area and the compressive force induces wrinkles. To determine the optimal roll speeds of current rough rolling system for wire rod, FE analysis was performed. We could predict the workpiece shape and the stress level more precisely by considering the elasto-plastic behavior of workpiece. Also the efficient analysis methodology is presented to reduce the calculation time by combining the ALE and lagrangian method.

• 한국정밀공학회지
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• 제8권4호
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• pp.33-40
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• 1991

The decrease in surface roughness of work roll and steel strip in cold rolling of low carbon steel strip has been investigated by working distance, materials, total separating force and total reduction ratio. The main results are as follows; For the same lubricating conditions. 1) The changing of surface roughness of steel strip were similar to work roll. The transcription ratio is in inverse proportion to the carbon content of steel strip. 2) The surface roughness of steel strip is hardly change according to changing of total separating force and total reduction ration. 3) The wear of work rolls surface is more rapid in that case of continuous casted steel strip than ingot casted steel strip. The aluminium content dull powder adhere on the rolls surface, and so. It makes the mirror surface of work roll accelerate.

• 대한기계학회논문집
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• 제14권5호
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• pp.1155-1165
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• 1990

본 연구에서는 롤압력과 롤토크를 예측하는 새로운 방법이 제시된다. 이 방 법은 롤 간극에서의 자세한 변형도속도의 분포를 예측할 수 있으며, 특히 롤압력과 롤 토크의 계산에 필요한 유동응력 분포도 계산할 수 있다. 이 방법을 이용하여 압연조 건과 재료성질이 롤압력, 압하력, 롤토그 등에 미치는 영향을 조사하였다. 또한, 이 방법에 의해서 예측된 결과를 참고문헌과 포항제철의 공정 데이터로부터 발췌한 실험 데이터와 비교하였으며, 유한요소 해석결과와도 비교하였다.

• 한국정밀공학회지
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• 제10권3호
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• pp.69-80
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• 1993

It is important to prevent roll failure in hot rolling process for reducing maintenance coat and production loss. Roll material and rolling conditions such as the roll force and torque have been intensively investigated to overcome the roll failures. In this study, a computer roll life prediction system under working condition is developed and evaluated on IBM-PC level. The system is composed and fatigue estimation models which are stress analysis, crack propagation, wear and fatigue estimation. Roll damage can be predicted by calculating the stress anplification, crack depth propagation and fatigue level in the roll using this computer model. The developed system is applied to a work roll in actual hot rolling process for reliability evaluation. Roll failures can be diagnosed and the propriety of current working condition can be determined through roll life prediction simulation.