• Title/Summary/Keyword: Hot Rolling Mill

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Application of hot rolling oil lubrication on RM stands at Pohang Hot Rolling Mill No.2 (포항2열연 조압연스탠드(RM) 유압연시스템의 개발과 적용)

  • 김철희;조준길;유문석;한영환
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 1997.10a
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    • pp.161-166
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    • 1997
  • Application of hot roiling oil lubrication technology was broadened to the field of RM stands of Hot Rolling Mill at Pohang works. The primary object was to improve the quality of the strip sttrface and the rolls by oil lubrication in hot rolling process. Prior to the actual field application preliminary test was conducted to evaluate the effect of hot rolling oil lubrication at RM stands. From the test, it has been found that the use of oil lubrication tends to prevent the progression of the heat cracks and thereby increases the quality of the strip surface and the wear life of the rolls. New hot rolling oil lubrication system was applied to the RM stands VSB, R1, R2, R3, R4 and edger rolls. With the introduction of a rolling lubricant, the quality of the strip surface and rolls was improved and overall roll dressing has decreased. Also there has been a improvement of productivity from the long roll life.

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Development of Hot Rolling Process Analysis Simulator and Its Application(I) (열간압연 공정 해석용 시뮬레이터의 개발과 응용(I))

  • 이원호;이상룡
    • Transactions of Materials Processing
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    • v.8 no.1
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    • pp.65-77
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    • 1999
  • In recent years, the quality requirements from the customers of hot rolled steel strip have been steadily increasing in diversity and strictness. To meet these quality requirements as well as to improve productivity, steel mills have been doing their efforts for developing high performance Automatic Gauge Control (AGC) system. However, it is very time consuming and also needs a lot of money to develop the new technologies of AGC in actual mill. So, there has been a demand for developing the Dynamic Hot Rolling Simulator since late 80's. It is a kind of software packages and can analyze the dynamic behaviors of hot finishing rolling process without laborious experiments in actual mill. It can also be used as a designing tool of Automatic Gauge Controller. In this work, the Dynamic Hot Rolling Simulator which is applicable to 6 sands hot strip mill rolling was developed. The MATLAB with SIMLINK was used as a software developer for making the main part of simulator because it is very powerful tool for modeling, integrating, controller design, and simulation. In this paper, the structures and the mathematical models of the simulator were briefly described and the results of simulation on the transient phenomena of hot rolling process with actual mill data were also presented.

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Investigation of Effect of Hot Rolling Oil of on Rolling with HSS Roll (고속도공구강롤을 적용한 열간유압연 사용특성 연구)

  • 유재희;황상무;김철희
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1997.10a
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    • pp.115-118
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    • 1997
  • Recently, hot rolling oil lubrication technology is required to face with the new environments such as the rapid introduction of high wear resistent high speed steel roll the development of continuous hot rolling technology. In the hot strip mill, according to rolling and quality required conditions are constrict, Roll material of hot rolling finishing stand is changing Hi-Cr Roll to High Speed Steel [HSS] Roll. The problem of HSS Roll of roll force and strip scale defects are increasing in hot strip mill, So we have tested HSS Roll in hot rolling simulator as rolling condition, rolling speed, draft, hot oil concentration. To reduce roll force and prevent scale defects. We get some merit rolling force, rolling torque, roll wear reduction, roll and strip surface roughness and hot rolling critical oil concentration 0.4%. Finally we are going to investigate the effect of hot rolling oil of on rolling with HSS Roll.

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Development of Technology for Setting Rolling Speed of Finishing Rolling Process in Hot Strip Mill (열연 마무리 압연공정 압연롤 회전속도 설정 기술 개발)

  • Hong, Seong-Cheol;Lee, Haiyoung
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.27 no.11
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    • pp.47-56
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    • 2013
  • Rolling speed, roll gap, and cooling pattern in hot strip finishing mill process should be determined before inserting strip into roll. Such parameters are initially calculated by a mathematical set-up model. The technique to find adequate roll speed via a mathematical model has inherently limit because required working conditions are various and rolling process is nonlinear. To improve the accuracy of initial rolling speed for a finishing mill, this paper suggests a correction technology for initial rolling speed. The proposed method was implemented in hot strip mill process. As the results, the magnitude of width error in strip head-end part caused by excessive strip tension was decreased remarkably.

Recent Trends in Flat Hot Rolling of Steel (열간 압연판재 제조기술의 최신동향)

  • 이준정
    • Transactions of Materials Processing
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    • v.11 no.1
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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.

Improvement of Thickness Accuracy in Hot-rolling Mill Using Neural Network and Genetic Algorithm (신경회로망과 유전자 알고리즘을 이용한 열연두께 정도 향상)

  • Son, Joon-Sik;Kim, Ill-Soo;Lee, Duk-Man;Kueon, Yeong-Seob
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.15 no.5
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    • pp.59-64
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    • 2006
  • The automation of hot rolling process requires the developments of several mathematical models for simulation and quantitative description of the industrial operations involved in order to achieve the continuously increasing productivity, flexibility and quality(dimensional accuracy, mechanical properties and surface properties). The mathematical modeling of hot rolling process has long been recognized to be a desirable approach to investigate rolling operating practice and design of mill requirement. To achieve this objectives, a new teaming method with neural network to improve the accuracy of rolling force prediction in hot rolling mill is developed. Also, Genetic Algorithm(GA) is applied to select the optimal structure of the neural network and compared with that of engineers experience. It is shown from this research that both structure selection methods can lead to similar results.

Analysis of Asymmetric Plate Rolling in Roughing Mill (열간 조압연에서 비대칭압연 해석)

  • Park H. D.;Chung J. H.;Bae W. B.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2000.10a
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    • pp.13-16
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    • 2000
  • In the hot strip mill, a bad threading and shape of strip strip in the finishing mill was caused by asymmetric rolling In roughing min. Mathematical analysis for camber control of roughing mill in hot strip rolling has been developed. Each equation in the camber control model was derived from geometrical characteristics of camber mechanism. The model can predict variables such as wedge, side slippage and roll force difference etc. from a measured camber value and then find an optimum roll gap condition for minimizing camber in the next pass.

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Control Scheme Using Forward Slip for a Multi-stand Hot Strip Rolling Mill

  • Moon, Young-Hoon;Jo, I-Seok;Chester J. Van Tyne
    • Journal of Mechanical Science and Technology
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    • v.18 no.6
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    • pp.972-978
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    • 2004
  • Forward slip is an important parameter often used in rolling-speed control models for tandem hot strip rolling mills. In a hot strip mill, on-line measurement of strip speed is inherently very difficult. Therefore, for the set-up of the finishing mill, a forward slip model is used to calculate the strip speed from roll circumferential velocity at each mill stand. Due to its complexity, most previous researches have used semi-empirical methods in determining values for the forward slip. Although these investigations may be useful in process design and control, they do not have a theoretical basis. In the present study, a better forward slip model has been developed, which provides for a better set-up and more precise control of the mill. Factors such as neutral point, friction coefficient, width spread, shape of deformation zone in the roll bite are incorporated into the model. Implementation of the new forward slip model for the control of a 7-stand hot strip tandem rolling mill shows significant improvement in roll speed set-up accuracy.

Plastic characteristic analysis of width reduction process in hot roughing mill (열간조압연 공정에서의 폭 압하 공정시 슬래브의 변형 특성)

  • Heo, Su-Jin;Lee, Sang-Ho;Byun, Sang-Min;Park, Hae-Do;Lee, Jong-Bin;Kim, Byung-Min
    • Proceedings of the KSME Conference
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    • 2007.05a
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    • pp.544-548
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    • 2007
  • In general, final width of hot strip should be accomplished in this stage because width reduction of strip hardly appears during typical finishing mill. However, it is difficult to control the width of strip in the roughing mill process as the horizontal rolling of strip is subsequently performed after the vertical rolling. It is therefore important to obtain the deformation rolling direction on strip width to minimize the width spread of strip during horizontal rolling after vertical rolling. Generally there is Sizing press type and Edger-roll type. The width reduction process in sizing press has small amount of width spread compared with the edger. However, productivity by the sizing press process is much lower than those of the edger. In this study, sizing press and Edger-roll process parameters in a sheet rolling mill were set at specified values and the effect of the change in these parameters on product quality and process performance were evaluated.

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Precise width control through the width spread compensation in hot strip mill (열간압연시 폭퍼짐 보상을 통한 폭정밀도 개선연구)

  • 천명식;이준정;문영훈
    • Transactions of Materials Processing
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    • v.8 no.2
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    • pp.200-207
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    • 1999
  • To increase dimensional accuracy of strip width, model to compensate width spread during roughing mill has been developed. To measure the amount of width spread during the production rolling more precisely, special roughing rolling procedures for the horizontal rolling and dog-bone rolling were designed in the actual production mill. From the operational data analysis, it is known that the prime factors influencing on the width spread were strip width, strip thickness, edging amount, number of pass and type of edger roll etc., Based upon the statistical analysis of rolling data, new models which can predict width spread during horizontal rolling and dog-bone rolling were developed and tested on the actual processing conditions for the reliability. The application test showed that newly developed model gave fairly accurate predictions on the width spread during roughing passes.

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