• Title/Summary/Keyword: Roll Flattening

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Analysis of the Rolling Contact Fatigue for Work Roll in Finishing Mill of Hot Strip Rolling (열간 연속판재 압연기의 작업롤 전동피로해석)

  • 배원병;박해두;송길호
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.1
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    • pp.292-300
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    • 1995
  • According to the number of cold-rolled coils, the amount of roll wear and thermal expansion, and roll gap profile were calculated, by using the actual data from the finishing mill. Also, based on those data, the calculations of the deflection, the flattening, and the contact pressure of vwork rolls and backup rolls were made respectively. Specially, in the calculation of contact pressure, the numerical results were obtained not only during the normal rolling, but also during the abnormal rolling, by modeling mathematically the dynamic impact force which occurs when the head section of the strip is threading through rolls. With those results the growth of the fatigue region and the fatigue damage of rolls were predicted. Also the optimum roll-grinding depth was determined to maximize the roll life.

A Study on the Cross Rolling for Improvement of Flatness of Plate (판재의 편평도 향상을 위한 교차압연에 관한 연구)

  • Nam K. O.;Seo K. S.;Rho B. R.;Hong S. I.
    • Transactions of Materials Processing
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    • v.14 no.1 s.73
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    • pp.43-48
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    • 2005
  • The production of metal strip with uniform thickness and flatness are two important problems associated thin strip rolling. The thickness and flatness of strip are affected by the flattening of contact surface between strip and roll, the elastic recovery and the bending of roll. Especially, the flatness of the strip is greatly affected by bending deflection of roll. The roll must be designed considered the elastic deformation of roll. This study describes the measurement of thickness and flatness of strip and shows the crown roll for producing flat strip. But it is difficult to produce the crown roller. The cross rolling that is a simple method which can produce the flat strip is introduced and it is found the optimal cross angle for improvement of flatness of plate. These problems are solved by the MARC code on the basis of elastic-plastic material and the updated Lagrangian formulation.

Technology of flatness control for high strength steel in hot strip mill (열간압연 고강도강 형상제어기술)

  • 박해두;송길호
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2003.05a
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    • pp.184-187
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    • 2003
  • The simulation program is developed to get the target strip crown of high strength steel in the continuous hot strip rolling. The developed program consists of several sub-program, which contains work roll shifting pattern, roll wear profile, roll thermal expanded profile and strip profile. Also, the variation of strip profile is investigated according to roll deflection and flattening. The results are compared with the values observed from the actual hot rolling of high strength steel. And effect of bender force on the strip profile is studied. The strip crown is shown to decrease with increasing bender force.

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냉연 강판의 폭방향 판두께 제어 기술

  • 배원형;박해두;최재찬
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1993.10a
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    • pp.512-517
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    • 1993
  • The cold rolled strip meets continuously rising demands on the less deviation of thickness at the width direction of their rolled products. Especially, the special interest has been to find the methods to reduce the edge drop which influences seriously on the yield losses and the quality of the rolled products. In this study, the influence of hot coils on the thickness profile of cold rolled strip was analyzed. For obtainint the tapered work roll shig\ft conditions, the thermal crown and the flattening between the work roll and the strip were calculated, and the main parameters which have mostly effects on the edge drop were simulated. Also the obtained conditions from the simulation were applied to Tandem Cold Rolling Mill to investigate the change of the edge drop and the crown ratio depending on the amount of work roll taper and the length of contact of taper. The results of the application led to better thickness profile than conventional one.

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Analysis of edge drop and development of numerical formula for edge drop control of cold rolled sheet (냉연판의 엣지드롭 해석 및 제어용 수식모델 개발)

  • Song, Gil-Ho;Park, Hae-Du;Jin, Cheol-Je;Sin, Seong-Gap
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.22 no.4
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    • pp.723-730
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    • 1998
  • With the introduction of edge drop control system in Tandem Cold Rolling Mill, it is necessary to develop te numerical expression for the set-up and edge drop automatic control of cold rolled sheet. As a first step we developed a simulation program which predicts profile and the amounts of edge drop at the delivery side of each stand by using roll deformation anlysis with the slit roll model. And by using the program the effect of various rolling conditions on edge drop was investigated. As a result the relations were obtained between the amounts of edge drop and rolling conditions. Based on above relations, the numerical expression was developed for the set-up and automatic control of edge drop by multi-regression of simulation results for the variation of edge drop amount with each rolling condition.

Optimization of the Tube Bending Process of Taguchi's Orthogonal Matrix (다구찌 직교배열을 이용한 트레일링 암 튜브 벤딩 공정 변수 최적화)

  • Yin, Z.H.;Chae, M.S.;Moon, K.J.;Kim, Y.S.
    • Transactions of Materials Processing
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    • v.18 no.1
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    • pp.67-72
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    • 2009
  • This paper covers finite element simulations to evaluate tube bending process of auto chassis component i.e. trailing-arm product. The rear of the auto chassis structure is primarily composed of CTBA and trailing-arm. When a car rolls into a corner, the trailing arm reacts to roll in the same degree as the car body. During the bending process of trailing arm the tube undergoes significant deformation. Thus forming defects such as excessive thinning and flattening of the tube will be formed in the outside of the tube. In this paper, we analyzed the effect of process parameters in rotary draw bending process and searched the optimized combination of process parameters using orthogonal arrays method to minimize the forming defects. In this process we analyzed several parameters which are displacement of pressure die, boosting force, initial position of mandrel bar, dimensions of mandrel in regarding to the thinning and flattening of the tube.

Roll Force Prediction of High-Strength Steel Using Foil Rolling Theory in Cold Skin Pass Rolling (고강도강의 냉간 조질 압연 시 호일 압연이론을 이용한 압연하중의 예측)

  • Song, Gil Ho;Jung, Jae Chook
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.37 no.2
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    • pp.271-277
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    • 2013
  • Skin pass rolling is a very important process for applying a certain elongation to a strip in the cold rolling and annealing processes, which play an important role in preventing the stretching of the yield point when the material is processed. The exact prediction of the rolling force is essential for obtaining a given elongation with the steel grade and strip size. Unlike hot rolling and cold rolling, skin pass rolling is used to apply an elongation of within 2% to the strip. Under a small reduction, it is difficult to predict the rolling force because the elastic deformation behavior of the rolls is complicated and a model for predicting the rolling force has not yet been established. Nevertheless, the exact prediction of the rolling force in skin pass rolling has gained increasing importance in recent times with the rapid development of high-strength steels for use in automobiles. In this study, the possibility of predicting the rolling force in skin pass rolling for producing various steel grades was examined using foil rolling theory, which is known to have similar elastic deformation behavior of rolls in the roll bite. It was found that a noncircular arc model is more accurate than a circular model in predicting the roll force of high-strength steel below TS 980 MPa in skin pass rolling.