• Title/Summary/Keyword: Cold rolling mill

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A Study on Development of Model for Prediction of Rolling Force in Tandem Cold Rolling Mill (연속냉간압연에서의 압하력 예측을 위한 모델 개발에 관한 연구)

  • 손준식
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2000.04a
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    • pp.491-496
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    • 2000
  • In the tandem cold rolling mill, the quality is very important and requirements for thickness accuracy become more strict. Howerver, the mathematical model for prediction of rolling force was not considered an elastic deformation at the entry and delivery side of the contacted area between the worked roll and rolling strip so that where was so difficult to control of the thickness. To overcome this problem, the 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 f the effect of elastic compression was not important.

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FEA of Copper Tube Rolling Process Using the Planetary Rolling Mill (유성압연기를 사용한 동관 압연공정의 유한요소해석)

  • Lee, Jung-Kil;Han, Ki-Beom;Kim, Kwan-Woo;Choe, Jong-Woong;Kim, Jae-Hun;Cho, Hae-Yong
    • Journal of Advanced Marine Engineering and Technology
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    • v.34 no.2
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    • pp.303-309
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    • 2010
  • Copper tube rolling process using the planetary rolling mill has been studied by using finite element method. This rolling is process that makes copper tube by three-roll with mannesmann method. Also, rolling process has started from the cold working and finished to the hot working. This rolling process has more advantage that make reduction of process and cost than existing extrusion. This process includes various and complex process parameters. Each of the process parameters affects forming result. Therefore, all of the process parameters should be considered in copper tube rolling. Rolling process for copper tube was successfully simulated and it should be useful to determine optimal rolling condition.

A Study on the Characteristics of Work Roll Texturing for Temper Mill

  • Kim, Soon Kyung;Kim, Moon Kyung;Shahajwalla, Veena;Chung, Uoo Chang
    • KSTLE International Journal
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    • v.2 no.1
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    • pp.80-84
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    • 2001
  • The purpose of this paper is to show the result from the study to improve the formability and appearance which is important in the cold rolled strip, the coated strip and prepainted strip. Furthermore, to give appropriate surface roughness, shape of work roll for temper mill is also important. The strip has a greater peak counts and homogeneous roughness. This makes the prepainted surface smooth and consistent in appearance with good image clarity. Therefore, the surface roughness of the work roll is very important. The reason that surface roughness of the work roll is transferred to the strip surface is the rolling farce and tension at the temper rolling or cold rolling. This study is classified in order to get an accurate and homogeneous roughness. There are few papers published in this field, because its importance is not known and the proper operation of the machine is not generally well known. This paper investigates the correlation between strip surface roughness and the surface of the work roll. After studying the surface roughness and shape according to the texturing method for roll surfaces at temper rolling, the findings were as follows. Irregular surface roughness can be compensated with several paint coatings, but this also makes the quality deteriorate and manufacturing costs go up.

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Mathematical Model for Cold Rolling and Temper Rolling Process of Thin Steel Strip

  • Lee, Won-Ho
    • Journal of Mechanical Science and Technology
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    • v.16 no.10
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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.

Development of New Back-Up Roll for Strip Shape Control (형상제어를 위한 새로운 보강롤의 개발)

  • Lee, Won-Ho
    • 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.

A study on the characteristics of hydraulic automatic gauge control system for a reversing cold mill (유압압하식 자동두께제어장치의 특성에 관한 연구)

  • Kim, Soon Kyung;Jeon, Eon Chan;Kim, Moon Kyung
    • Journal of the Korean Society for Precision Engineering
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    • v.13 no.3
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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.

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Fabrication of Drawing Wire for Cold Rolling Mill using Tungsten Carbide Multi-Stage Dies (초경 다단 다이를 적용한 냉간 압조용 인발 선재 제조)

  • Park, D.H.;Hyun, K.H.;Lee, M.J.
    • Transactions of Materials Processing
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    • v.29 no.2
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    • pp.97-102
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    • 2020
  • Wire drawing is a metalworking process used to reduce the cross-section of a wire by pulling the wire through multi-stage drawing dies. The aim of this study is to fabricate a drawing wire using 2 stage drawing process. The finite element analysis of wire drawing was conducted to validate the efficiency of the designed process and the experiment was performed to validate the designed wire drawing process using 2 stage tungsten carbide die. Dry lubricant with powder was applied for producing a wire of desired diameter. Finally, a drawing wire using 2 stage die for cold rolling mill was developed.

Strip Rupture Detection System of Cold Rolling Mill using Transient Current Signal (과도 전류신호를 이용한 냉간 압연기의 판 터짐 검지 시스템)

  • Yang, S.W.;Oh, J.S.;Shim, M.C.;Kim, S.J.;Yang, B.S.;Lee, W.H.
    • Journal of Power System Engineering
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    • v.14 no.2
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    • pp.40-47
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    • 2010
  • This paper proposes a fault detection system to detect the strip rupture in six-high stand Cold Rolling Mills based on transient current signal of an electrical motor. For this work, signal smoothing technique is used to highlight precise feature between normal and fault condition. Subtracting the smoothed signal from the original signal gives the residuals that contains the information related to the normal or faulty condition. Using residual signal, discrete wavelet transform is performed and acquire the signal presenting fault feature well. Also, feature extraction and classification are executed by using PCA, KPCA and SVM. The actual data is acquired from POSCO for validating the proposed method.

Mathematical Model of Rolling Force Estimation in Strip Cold Mill (박판 냉간압연공정에 있어서의 압연하중 예측모델에 관한 연구)

  • Baek, Nam-Joo;Kim, Jin-Wook;Park, Hae-Doo;Cho, Yong-Yee;Kim, Hee-Song
    • Journal of the Korean Society for Precision Engineering
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    • v.7 no.4
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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.

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A Fuzzy Shape Control Method for the Stainless Steel at the Cold Rolling Process (스테인리스 냉연공정에서 퍼지 형상제어)

  • Hur, Yone-Gi
    • Journal of Institute of Control, Robotics and Systems
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    • v.15 no.10
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    • pp.1062-1070
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    • 2009
  • The strip shape for the stainless steel process has made an issue of the strip quality, and hence the shape control method is developed at the Sendzimir rolling mill (ZRM). ZRM is a stainless cold rolling mill and has actuators for the shape control. They are first intermediate rolls and top crown rolls, which are controlled horizontally and vertically, respectively. The shape control of the stainless steel rolling process has difficulty in obtaining the symmetrical shape. The objective of the shape control is to minimize the shape deviation and to maintain stable state, which keeps symmetrical shape pattern in the lateral direction. The method of the shape recognition employs a least squares method and neural network. The shape deviation is the difference between the target shape and actual shape and is controlled by the fuzzy shape control. The fuzzy shape control using operator's informative knowledge is proposed in this paper. The experiments are carried out online for various stainless materials and sizes. The productivity of the rolling process has increased from 9.0 to 9.4 tons per hour.