• Title, Summary, Keyword: Hot Rolling

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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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    • 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 Hot Rolling Wear Simulator and Roll Wear (강판의 열간윤활압연특성 연구I (열간압연마모 시험기의 개발과 시험))

  • 김철희
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • pp.126-132
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    • 1996
  • A laboratory scale hot strip rolling wear simulator(HRWS) was developed for the purpose of investigating the tribological phenomena occurred in production hot strip rolling mills. The HRWS' main parts are the electric heater, the mechanical descaler, tandem type 2-4Hi rolling mill stands, the cooling chamber, the tension controller and coiler. By simulating the tribelogical phenomena in rolling process at laboratory, wear patterns, cracks, cat-ear wear, black film, effect of hot rolling oil lubrication, etc. were reproduced, and discussed on the performace of simulator.

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Effect of Lubrication during Hot Rolling on the Evolution of Textures at the surface of 18%Cr Ferritic Stainless Steel Sheet (페라이트계 스테인리스 강의 열간압연 시 표면 층의 집합조직 발달에 미치는 윤활의 영향)

  • Pyon, Y.B.;Kang, H.G.;Huh, M.Y.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • pp.411-414
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    • 2008
  • In order to study the effect of lubrication during hot rolling, ferritic stainless steel (FSS) sheet were hot-rolled with and without application of lubrication. The effect of two hot rolling processes on the evolution of texture and microstructure after hot rolling, cold rolling and subsequent recrystallization annealing was studied by means of macro-texture analysis and microstructure observations. After hot rolling, the specimen rolled with lubrication showed rolling textures at the sheet surface, while the specimen rolled without lubrication displayed shear textures in the outer layers of the sheet. Hot rolling with lubrication was beneficial to the formation of strong recrystallization textures at sheet surface. However, hot rolling with lubrication led to the formation of orientation colonies in outer thickness layers of the recrystallized sheet.

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Microstructure and Mechanical Property of Aluminum Powder Compact by Powder-in Sheath Rolling Method (분말시스압연법에 의해 제조된 알루미늄 분말성형체의 조직 및 기계적 성질)

  • 이성희
    • Journal of Korean Powder Metallurgy Institute
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    • v.9 no.3
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    • pp.153-160
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    • 2002
  • A nitrogen gas atomized aluminum powder was consolidated by powder-in sheath rolling method. A pure aluminum tube with outer diameter of 12 mm and wall thickness of 1mm was used as a sheath. The aluminum tube filled with the aluminum powder, first, was cold-rolled to the thickness of 6mm for performing, and then consolidated by the cold rolling and/or subsequent hot rolling at 360, 460 and $560^{\circ}C$. The aluminum powder compact fabricated by the sheath rolling showed high relative density more than 0.96 at any rolling conditions. The 0.2% proof stress increased with increasing hot rolling reduction and hot rolling temperature. Tensile strength was hardly affected by change in the hot rolling reduction, whereas it decreased with increasing hot rolling temperature. The powder compact showed the large elongation when cold rolling or hot rolling reduction was large. It was found that the sheath rolling was an effective method for consolidation of aluminum powder.

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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    • 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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Tension Estimation of Interstand Strip in Looperless Hot Rolling Process Using SVR (SVR을 이용한 Looperless 열연 공정에서의 스텐드간 장력 추정)

  • Han, Dong-Chang;Shim, Jun-Hong;Park, Cheol-Jae;Park, Hae-Doo;Lee, Suk-Gyu
    • Journal of Institute of Control, Robotics and Systems
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    • v.13 no.10
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    • pp.1007-1011
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    • 2007
  • This paper proposes a novel tension estimation of interstand strip in looperless hot rolling process using SVR(Support Vector Regression). The quality of hot coil which is final product of hot rolling process is substantially decided by tension control of finishing rolling in hot rolling process. The fluctuation of the strip tension in conventional hot rolling process is controlled by the strip tension measured by an inter-stand looper. However, the looper can cause a motor trip and tension hunting in hot rolling process, therefore, alternative method is essential to replace it. In this paper, the mathematical modeling of tension mechanism is implemented to estimate the tension using the proposed SVR algorithm without looper in hot rolling process. The simulation results show a reliable estimation performance and a possibility of tension control using SVR technique.

Effect of Asymmetric Hot Rolling on the Texture Evolution of Fe-3%Si Steel

  • Na, Tae-Wook;Park, Hyung-Ki;Park, Chang-Soo;Joo, Hyung-Don;Park, Jong-Tae;Han, Heung Nam;Hwang, Nong-Moon
    • Metals and materials international
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    • v.24 no.6
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    • pp.1369-1375
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    • 2018
  • In Fe-3%Si steel, the hot rolling process affects not only the hot rolling texture but also the primary recrystallization texture. Here, the effect of asymmetric hot rolling was studied by comparing the difference in the texture evolved between asymmetric and symmetric hot rolling. The effect of asymmetric hot rolling on the texture of primary recrystallized Fe-3%Si steel was also studied. The symmetric hot rolling of Fe-3%Si steel produces a rotated cube texture at the center but Goss and copper textures near the surface. Asymmetric hot rolling tends to produce Goss and copper textures even at the center like the texture near the surface. After primary recrystallization, the dominant texture at the center changes from {001} <210> to {111} <112> and the new texture has a higher fraction of the grains which make the low energy boundary with Goss grains than that of symmetric hot rolling.

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.

Size-controlled Growth of Fe Nanoparticles in Gas Flow Sputtering Process

  • Sakuma, H.;Aoshima, H.;Ishii, K.
    • Journal of Magnetics
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    • v.11 no.3
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    • pp.103-107
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    • 2006
  • In grain oriented electrical steel process, hot band annealing has thought to be essential for obtaining good magnetic properties. New hot rolling method of heavy reduction in early hot rolling stage was applied to obtain good magnetic properties in GO process without hot band annealing. Hot rolling was carried out by varyinghot rolling reduction distribution along hot rolling pass. The heavy hot rolling reduction in rear stand improves the magnetic flux density in the case of no hot band annealing. The hot band specimens of the heavy reduction in front stand shows the elongated hot deformed microstructures in the center layer and strong {001}<110> texture.On the contrary, the heavily reduced specimens in rear stand shows the recrystallization in the center layer of hot band and strong {111}<112> and {110}<001> textures.

An Analysis of Hot-Rolling in the Twin-Roll Strip Casting Process by using the Slab Method (슬랩법을 이용한 쌍롤식 박판주조 공정의 열간 압연 해석)

  • Shim, Hyun-Bo
    • Transactions of Materials Processing
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    • v.3 no.1
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    • pp.63-83
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    • 1994
  • In this paper, the slab method have been applied to investigate the strip casting process in which hot coil is produced from molten steel directly. In the twin roll strip casting process, molten steel supplied by the nozzle cools and solidifies due to the heat extraction effect of the rolls and hot rolling of the solidified shell takes place simultaneously. The analysis of hot rolling has been carried out by using the existing results of solidification analysis for the twin roll strip casting process. The current slab method provides basic design data such as roll separation force, rolling torque, rolling power as well as end dam separation force which are required to design strip caster. The effect of friction on the basic process parameters are investigated also. It is shown that the use of appropriate friction coefficient is important and that the characteristics of hot rolling in the twin-roll strip casting process is quite different from the conventional hot rolling processes.

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