• 한국공작기계학회논문집
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• 제10권5호
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• pp.96-103
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• 2001

The quality requirements for thickness accuracy in cold rolling continue to become more stringent, particularly in response to exacting design specification from automotive customers. One of the major impacts from the tighter tolerance level is more unusable product on the head end and tail end of tandem mill coils when the mill is in transition to or from steady state rolling condition. A strip thickness control system for a tandem cold steel rolling mills is composed with blocked non-interacting controller and controllers for strip thickness and tension control of each rolling stands. An intelligent mathematical model included an elastic deformation of strip has been developed and applied to the field in order to predict the rolling force. The simulated results showed that the effect of elastic recovery should be included the model, even if the effect of elastic compression was not important.

• 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mill process, precalculation determines the mill settings before a strip actually enters the mill and is done by an outdated mathematical model.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.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1999년도 제3회 압연심포지엄 논문집 압연기술의 미래개척 (Exploitation of Future Rolling Technologies)
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• pp.308-312
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• 1999

Developed the model equations which calculate roll force, roll power during hot rolling in real time. The variables which mainly effect on the roll force, roll power are shape factor, reduction, roll diameter, roll velocity, strip inlet temperature, carbon content of strip and strip-roll contact friction coefficient. Among these variables roll diameter, roll velocity, inlet temperature, carbon content and friction coefficient can be excluded in interpolated model equation by introducing equation of die force(F'), power(p') of the frictionless uniform plane strain compression which can be calculated without iteration. At the case of coulomb friction coefficient of 0.3, we evaluated coefficient of polynomial equations of {{{{ { F} over {F' } }}}}, {{{{ { Pf} over {Pd }, { Pd} over {P' } }}}} from the result of finite element analysis using interpolation. It was found that the change of values of {{{{ { F} over {F' }, { P} over {P' } }}}} with the friction coefficient tend to straight line which slope depend only on shape factor. With these properties, developed model equations could be extended to other values of coulomb friction coefficient. To verify developed roll force, roll power model equation we compared the results from these model equation with the results from these model equation with the results from finite element analysis in factory process condition.

• 소성∙가공
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• 제28권4호
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• pp.197-202
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• 2019

This paper proposes a precise mathematical model for the prediction of the variation of the roll force across a strip in cold rolling. It further describes the deformation characteristics of the strip using a 3-D finite element method. The different features of hot rolling and cold rolling through a 3-D finite element method are shown. The predicted roll force profile and tension profile are verified through comparison with the prediction from a 3-D finite element method.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2011년도 춘계학술대회 논문집
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• pp.479-480
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• 2011

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 추계학술대회 논문집
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• pp.281-282
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• 2010

• 대한기계학회논문집A
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• 제24권11호
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• pp.2836-2844
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• 2000

Thickness control of hot-rolled strips has become an important issue in recent years because of the need for improving the quality of the hot-rolled strip. In this study, a modifying method of rolling force set-up with consideration of spread was developed to improve the thickness uniformity at the finishing rolling units in hot rolling. Through the analysis of real production data it was found that the accuracy of the rolling force determined from the finishing mill set-up (FSU) model dominantly governed the thickness uniformity in rolled plates at the front. Based on this analysis , several examples were selected to calculate the spread of rolled plate using three dimensional rigid thermo-viscoplastic finite element program. FE analysis results were used to train the neural network system that can predict the spread hot-rolled plate and the rolling force was modified based on the predicted value of spread. The modified rolling forces were closer to the measured rolling force so it can be expected that the accuracy of thickness uniformity of hot-rolled plate will be improved.

• 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.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 제5회 압연심포지엄 신 시장 개척을 위한 압연기술
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• pp.368-377
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• 2004

A mathematical model was developed for the prediction of the average temperature and RDT(RM Delivery temperature) in a roughing mill. The model consisted of three parts as follows (1) The intermediate numerical model calculated the deformation and heat transfer phenomena in the rolling: region by steady state FEM and the heat transfer phenomena in the interpass region by unsteady state FEM (2) The Off-line prediction model was derived from non-linear regression analysis based on the results of intermediate numerical model considering the various rolling conditions, (3) Using the heat flux in rolling region, temperature profile along thickness direction was calculated. For validation of the presented model, the rolling force per pass and RDT measued in on-line process was compared with those of model and the results showed close agreement with the existing data. In order to demonstrate the effectiveness of the proposed model, the various rolling conditions was tested.

• 한국정밀공학회지
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• 제7권4호
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• pp.140-148
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• 1990

A mathemetical medel has been developed for the purpose of estimating the rolling force required for computer control of cold strip mills. The model consists of equations of rolling force. flow stress. friction coefficient and tension. By applying the model to a 6-High cold tandem mill, the computer simulation is then been possible for all kinds of steels except stainless steel and the effectiveness of the model has been confirmed in the practice.