• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.2
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• pp.327-333
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• 2003

Most of shape defects in steel strip are originated from the structure of rolling mill itself. For instance, strip crown occurs when the work roll is deformed by the bending moment induced on roll chocks. To get rids of the shape defects, it is necessary to increase the stiffness of rolling mill. The structure change of back-up roll is one of alternative ways to increase the mill stiffness without facility revamping from 4 high mill to 6 high mill. In this research work, the new back-up roll was developed and can be used in any type of 4 high mill to reduce the strip shape defects. The developed back-up roll consists of sleeve, arbor and phase angle adjusting system for arbor. The circumference of arbor is specially machined to adapt the strip width change during rolling. The experimental cold rolling test was done to prove the effectiveness of newly developed back-up roll. The experimental rolling results show that the new back-up roll has more powerful performance in reducing the shape defects than conventional back-up roll. It was also found that the new back-up roll has higher stability for shape control. In addition to, the only sleeve surface needs to be reground and changed in most cases, so that the maintenance cost can be greatly reduced.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.11
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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.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.38-38
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• 2000

To fulfill recent requirements for high quality products in steel rolling process, fast responding and easily tunab control system is required and ILQ(Inverse Linear Quadratic) control system may be one of such alternatives. In this paper characteristics of ILQ control and its application to BUR(Back-Up-Roll) eccentricity in strip rolling mill is discussed and compared to polynomial control approaches. Also the rolling mill model and basic principle to control thickness of srip are introduced with control effect by polynomial methods.

• Journal of the Korean Society of Clothing and Textiles
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• v.10 no.3
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• pp.27-36
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• 1986

The purpose of this study was, to estimate the detergency of commercial detergent and to examine the interrelationship between detergency and detergent characteristics, detergent concentration, fiber characteristics, and Rolling-up phenomenon which is the major removal mechanism of oily soil. A mixture of oleic acid-olive oil was used as oily soil. The detergency was estimated by analysis of oleic acid on cotton ana polyester fabrics before and after washing by means of liquid scintillation counting. The Rolling-up of oily soil from PET film was observed and change of contact angle and removal time were measured. The results were as follows ; 1. In the case of soaps and powder synthetic detergents, the optimum concentrations we-re about $0.2\~0.3\%$. And detergencies of liquid synthetic detergents were considerably low, and the detergency was continually increased up with increasing concentration to $0.5\%$, which seemed to be caused by the lower pH than that of soap and powder synthetic deter-gent solutions. 2. As the effect of external or internal fiber structure; the detergency of cotton was lower than that of polyester. 3. In the observation of Rolling-up, the contact angle increased and the Rolling-up time became shorter with increasing detergent concentrations ($0.05\~0.5\%$). And it was confirmed that detergency was increased with Rolling-up effect. In addition, the study on the actual laundry condition was studied using the questionaire. From the results, about $76\%$ of households used the concentration of detergent roughly or excessively and housewives were highly concerned on the recommended dose, but grade of practice were very low.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.252-255
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• 2009

The roll gap set-up in the finishing mill is one of the most important technologies in the hot plate rolling process. As the target thickness can be obtained by the correct set-up of the roll gap, improving the roll gap set-up technology is very critical for plate thickness accuracy. The main cause of thickness variation in hot plate mills is the non-uniform temperature distribution along the length of the slab. The objective of this study is to adjust the roll gap set-up for the thickness accuracy of plate in hot rolling process considering top-end temperature drop. Therefore this study has concentrated on determining the correct amounts of roll gap to compensate thickness variation due to top-end temperature drop. The off-line simulation of compensated roil gap significantly decreases top-end thickness variation.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1323-1326
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• 2003

In this paper, we propose set-up model of silicon steel cold rolling mill. Until now, the working of Silicon Steel is operated using the look-up table value of roll force which a field operator finds by making good use of his experience. Therefore, the standardization of data and an improvement of the quality on product are very difficult. So we establish neural model using field data of various kinds of coil at each pass.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.10a
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• pp.93-95
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• 2007

Studies on ski-end shape control at the top end of rolling plate in heavy thick plate mill by using FEM analysis and measuring system have been performed. Plate shape behaviour at the top-end on rolling by the two different methods in finishing rolling process has been observed. One is to minimize the height of ski-end by using pass line based on the relational model between shape factor and pick-up and the other one is to prevent turn down problem caused by the impact between table roller and down bended plate on rolling by using roll speed difference. To minimize the height of ski-end, the prediction models based on the FEM analysis and measuring data was developed. The control method of ski - end shape on finishing rolling process was applied in actual mill and the height of ski-end was reduced by about 50% compared with conventional operation.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.3
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• pp.1-14
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• 2013

In this paper, a finite element analysis technique of rolling stock models for collision-induced derailments was suggested using rolling contacts for wheel-rail interaction. The collision-induced derailments of rolling stock can be categorized into two patterns of wheel-climb and wheel-lift according to the friction direction between wheel flange and rail. The wheel-climb derailment types are classified as Climb-up, Climb/roll-over and Roll-over-C types, and the wheel-lift derailment types as Slip-up, Slip/roll-over and Roll-over-L types. To verify the rolling contact simulations for wheel-rail interaction, dynamic simulations of a single wheelset using Recurdyn of Functionbay and Ls-Dyna of LSTC were performed and compared for the 6-typical derailments. The collision-induced derailment simulation of the finite element model of KHST (Korean High Speed Train) was conducted and verified using the theoretical predictions of a simplified wheel-set model proposed for each derailment type.

• Transactions of Materials Processing
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• v.10 no.2
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• pp.130-136
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• 2001

The mathematical set-up model was developed to reduce the mechanical property deviation in annealed and slightly rolled steel strip. The mechanical peculiarities of skin pass rolling process, such as high friction value and non-circular contact arc, low reduction and non-negligible entry and exit elastic zones as well as central restricted deformation zone are all taken into account. The deformation of work rolls is calculated with the influence function method and arbitrary contact arc shape is permitted. The strip deformation is modeled by slab method and the entry and exit elastic deformation zones are included. The strip restricted deformation zone near the neutral point is also considered. It was revealed that the new model has better accuracy than present regression model by statistical analysis with actual mill rolling data.

• Transactions of Materials Processing
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• v.18 no.4
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• pp.290-295
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• 2009

The roll gap set-up in the finishing mill is one of the most important technologies in the hot plate rolling process. As the target thickness can be obtained by the correct set-up of the roll gap, improving the roll gap set-up technology is very critical for plate thickness accuracy. The main cause of thickness variation in hot plate mills is the non-uniform temperature distribution along the length of the slab. The objective of this study is to adjust the roll gap set-up for the thickness accuracy of plate in hot rolling process considering top-end temperature drop. Therefore this study has concentrated on determining the correct amounts of thickness variation according to top-end temperature drop and roll gap to compensate thickness variation. The control method of roll gap set-up which can improve the thickness accuracy was proposed. The off-line simulation of compensated roll gap significantly decreases top-end thickness variation.