• Title/Summary/Keyword: Rolling Up

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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.

Development of Rolling Speed Set-up Model for the Travelling Stability in Hot Strip Finishing Mill (열간사상압연 통판안정성 개선을 위한 속도설정모델 개발)

  • 문영훈;김영환
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1999.08a
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    • pp.47-56
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    • 1999
  • New rolling speed prediction model has been developed for the precise presetting rolling speed of each finishing mill stand in the tandem hot strip mill. Those factors such as neutral point, work roll diameter, rolling torque, friction coefficient, bite angle and the thickness at each side of entry and deliver of the rolls were taken into account. To consider width effect on forward slip, calibration factors obtained from rolling torque has been added to new prediction model and refining method has also been developed to reduce the speed unbalance between adjacent stands. The application of the new model showed a good agreement in rolling speeds between the predictions and the actual measurements, and the standard deviation of prediction error has also been significantly reduced.

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Deformation Behavior during Warm Rolling in AA3103 Sheet deformed by CCSS (CCSS 가공한 AA3103 판재에서 온간 압연 소성 거동)

  • Lee J. P.;Kang H. K.;Huh M. Y.;Park J. W.;Chung Y. H.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2004.10a
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    • pp.215-217
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    • 2004
  • In order to obtain the initial starting sample having a random texture and fine grains, aluminum alloy 3103 sheets were repeatedly deformed by CCSS up to six passages and subsequently annealed at $300^{\circ}C$ for 1h. These samples were cold rolled at room temperature and also warm rolled at $250^{\circ}C$. Changes in rolling temperature gave rise to the different texture evolution. Warm rolling led to the pronounced texture gradients comprising the shear texture at the surface and the rolling texture at the sheet center. The formation of the rolling texture components, i.e., the ${\beta}$-fiber, was promoted by cold rolling than warm rolling.

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Deformation Behavior of $CU_{54}Ni_6Zr_{22}Ti_{18}$ Bulk Amorphous Alloy during Multi-Pass Warm Rolling (동계 벌크 아몰퍼스의 다단 온간 압연시 변형 거동)

  • Park E. S.;Kim H. J.;Bae J. C.;Huh M. Y.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2005.10a
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    • pp.139-142
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    • 2005
  • Cu-Ni-Zr-Ti bulk amorphous thin strips were produced by multi-pass warm rolling of the amorphous powder at temperatures in the supercooled liquid region. Process variables for rolling of the bulk amorphous strips were properly controlled to prevent onset of crystallization and failure during rolling up to three passes. During rolling of the amorphous powder, both the deformation and densification took place and the newly developed surface on the deformed amorphous particles enhances the consolidation leading to an increase in the strength. The strain state during rolling was analyzed by FEM.

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Improvement of Edge Drop in Cold Rolled Steel by Tapered Work Roll in Tandem Cold Mill (탠덤압연설비에서 테이퍼롤 채용에 의한 냉연강판 에지드롭 개선)

  • 한석영;이준정
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.1
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    • pp.34-43
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    • 1994
  • In order to improve thickness profile of cold rolled steel strip, a computer simulation and actual cold rolling experiments on a 4-high tandem cold mill were carried out. In this study, tapered barrel end at top work roll and incurved barrel body at bottom work roll were examined for reducing edge drop and threading of stripe. Also, the most effective stand of tandem cold mill and magnitude of optimal taper crown at several stand were investigated under a typical rolling condition. From actual rolling experiments, it was verified that thickness deviation over strip width could be improved up to 1.06% by applying tapered and incurved work roll only at the second and up to 0.89% by applying them at both the second and the third stand.

Effect of Composition and Microstructure of Si$_3$N$_4$ Ball OH Rolling fatigue Life under Boundary Lubrication (경제윤활하에서 질화규소몰의 미세구조 및 조성이 구름피로수명에 미치는 영향)

  • 최인혁;송복한;신동우
    • Tribology and Lubricants
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    • v.16 no.6
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    • pp.477-483
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    • 2000
  • Rolling contact fatigue (RCF) tests were performed for two kinds of commercial silicon nitride balls using 4-Ball rolling contact fatigue life tester under EHL condition (Λ=8.9) and boundary lubrication condition (Λ=0.2). All the test balls were finished up to the dimensional accuracy of Grade 5 defined in KS B 2001 (Steel Balls for Ball Bearings) with a size of 8.731 mm. RCF tests were then conducted under the initial theoretical maximum contact stress 6.63 GPa and the spindle speed 10,000 rpm. All the test balls were not failed until 3.75 $\times$ 107 contact cycles and wear tracks of test balls were not conspicuous under EHL condition (Λ= 8.9). In the operations of low lambda regime (Λ= 0.2), all the test balls were surface damaged and high rolling wear resistance was achievable in fully densified using MgO 1 wt% and HIPed balls. Rolling wear of silicon nitride balls under boundary lubrication condition depend mainly on grain size and intergranular phase content of silicon nitride balls.

Recent Trend in Hot Rolling Technology of Steels (강판 열간압연의 기술개발 동향)

  • 신수철
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1999.08a
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    • pp.3-9
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    • 1999
  • The recent technical trend in hot rolling of steel can be described as process and product technologies which have been progressed with modern mill equipment and computers. Precise gauge and width control can be achieved by up-to-date control methods such as AGC and AWC systems. Roll benders and various shape control systems enabled high quality flatness and crown control. Mills can produce higher tensile materials by new process based on process metallurgy. The use of high speed steel rolls and on line roll grinders make the schedule free rolling easier which results in cost saving. Process itself goes toward continuous and simple flow type which has lower operation. Endless rolling and strip casting are examples of the trend. Materials with higher tensile strength and various functions have been developed in last years to meet the customer's needs and this trend will continue.

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Rolling Contact Fatigue of Hot-forged Steels out of Prealloyed Powders and Powder Blend

  • Dorofeyev, Vladimir;Sviridova, Anna
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2006.09a
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    • pp.559-560
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    • 2006
  • Powder forging is used for heavy-loaded parts (rings of rolling-contact bearings, gears etc.) production. Rolling contact fatigue is material property values of which characterize possibility of practical utilization of such parts. Rolling contact fatigue of some steels obtained out of prealloyed powders Astaloy CrM, Atomet 4601, Atomet 4901 and powder blends iron-carbon-nickel by hot forging is studied in the present paper. Effect of various kinds of heat and thermomechanical treatment on rolling contact fatigue is determined. Thermomechanical treatment provides optimal values of rolling contact fatigue. In this case steel structure contains up to 40% of retained metastable austenite which is transformed to martensite on trials. Thus typically crack is generated on residual pores and non-metallic inclusions instead of martensite zones in wrought steels.

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Roll deformation and wear analysis of backup roll in heavy plate mill (후판압연의 백업롤 변형해석 및 마모특성 분석)

  • Seo, Jae-Hyung;Gho, Sung-Hyun;Moon, Chang-Ho;Chun, Myung-Sik;Park, Hae-Doo
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2009.04a
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    • pp.62-64
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    • 2009
  • Control of back-up roll deformation and wear profile in plate rolling is important not only for enhancement of the structural precision of mill, but also for improving the yield and rolling operation. in the heavy plate mill, there have been strong demands for upgrading back up roll operation technology. In order to satisfy these demands, it is essential to develop the backup roll deformation analysis models and wear profile prediction models. This paper gives a general description of the backup roll deformation and wear model, simulation result for deformation analysis and wear profile.

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A Revamping of Pickling and Tandem Cold Rolling Mill for Producing Stainless Steel (Stainless 생산을 위한 냉연 합리화)

  • Lee D. H.;Ki E. D.;Cho S. B.;Lee K. B.;Kim D. H.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2004.08a
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    • pp.109-118
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    • 2004
  • No.2 PCM (Pickling and tandem cold rolling mill) at Pohang works was revamped in 2003. The purpose of this project is to produce carbon and stainless steel using conventional carbon production process, rolling and annealing. This paper introduces the applied facilities and technologies of PCM which are used in production of carbon and stainless steel. To realize the main purpose of this project, POSCO have developed laser weld technology in normal carbon and special steel (stainless, high carbon and high silicon). And this report describes the method which is developed to get down the surface defect of stainless 400 series. After revamping, No.2 PCM can have competitive power in this field and can supply the special steel using carbon rolling process.

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