• Title/Summary/Keyword: Roll Crown

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The Relaion between Cold Rolling Factors and the Edge Drop (냉연 작업인자와 edge drop의 상관관계)

  • Yeo W. K.;Hwang S. M.;Chung J. S.;Kim J.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2001.10a
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    • pp.142-146
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    • 2001
  • In this study, it was investigated the influence of cold rolling factors on the edge drop. Edge drop was highly affected by the shape of work roll, the amount of work roll shift and the crown of hot strip, but the effect of bending force at the front stand was relatively small. The used numerical model was examined by comparing to the result of measured field data, and it showed a qualitative agreement with each other.

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A Robust Design Study of Air Bearing Slider for HDD (HDD용 에어베어링 슬라이더의 강건설계에 관한 연구)

  • 전규찬;장동섭;좌성훈
    • Tribology and Lubricants
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    • v.16 no.4
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    • pp.247-252
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    • 2000
  • As the demand for higher areal recording densities requires a lower flying height of the slider, the variation of the flying height of the slider during drive operation becomes of great concern. The variation of the flying height is closely related with the slider design parameters such as air bearing shape, cavity depth, shallow step depth, crown, camber, pitch offset, roll offset, gram load, and so on. The objective of this work is to optimize the cavity depth and the shallow step depth, which are the control factors in air bearing design, using Robust Design method. It was found that the shallow step depth was statistically significant in affecting the variation of flying height, therefore the level of the shallow step depth should be chosen to minimize the variation of flying height.

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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Study on the thickness precision of rolled sheets (압연판의 두께 정밀도에 관한 연구)

  • 김동원;윤상건
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.11 no.5
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    • pp.837-845
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    • 1987
  • In the research of the rolling of strip, producing the strip with a close tolerance of thickness over the rolling direction was a principal object. But it was solved by the contribution of two-dimensional theory of rolling and the development of automatic gauge control system. And new requirements for the study of flatness, crown of rolled strip and edge drop grow up recently. These phenomena are closely related with the thickness distribution along the lateral direction of rolled strip. To analyse the thickness distribution of rolled strip along the lateral direction, elastic deformation of rolls and plastic deformation of work material must be discussed simultaneously. In this report, an approximate three-dimensional analysis based on Tozawa's three dimensional approach was applied to 12 cases of different rolling conditions and the numerical results were investigated. Especially stresses were laid upon the investigation of optimal boundary position between the three-dimensional analysis region and the plane strain analysis region.

Development of The New Shape Control Algorithm with The Strip Thickness Decoupling in Hot Strip Mill

  • Dukbum Shin;Kim, Jongcheol;Sangchul Won
    • 제어로봇시스템학회:학술대회논문집
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    • 2001.10a
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    • pp.175.2-175
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    • 2001
  • The strip profile and shape control is one of the most important technologies in Hot Rolling Mill System. Because the unbalance of strip´s shape and wave appearance between stands has a bad effect on Hot Rolling Mill System by making the inferior thickness, strip´s damage and so forth in factories. Many competition Plate Mill introduced shape control system, for example, pair cross-mill, work roll bender, which includes shape measuring instruments and shape control mathematical models. Shape meter, which is equipped for flatness, only does feedback control at the top of coil. And, for crown, we depend on initial setup value and there is no feedback control. Therefore we predict the shape of strip using rolling pressure, bender force and tension of inter-stand in ...

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Seasonal Fluctuation and Distribution of Obolodiplosis robiniae (Diptera: Cecidomyiidae) Within Crown of Robinia pseudoacacia (Fabaceae) (아까시잎혹파리, Obolodiplosis robiniae (Diptera: Cecidomyiidae) 연간 밀도변동과 아까시나무 수관 내 분포)

  • Lee, Jung-Su;Jung, Yu-Mi;Choi, Kwang-Sik;Kim, Il-Kwon;Kwon, Young-Dae;Jeon, Mun-Jang;Shin, Sang-Chul;Choi, Won-IL
    • Korean journal of applied entomology
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    • v.48 no.4
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    • pp.447-451
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    • 2009
  • Locust gall midge (LGM), Obolodiplosis robiniae (Haldeman) (Diptera: Cecidomyiidae), is a cecidomyiid insect forming roll-up galls on leaves of Robinia pseudoacacia Linnaeus (Fabaceae). LGM, known as native to North America, was reported from Korea and Japan in 2002. LGM was observed weekly or biweekly to clarify their voltinism and distribution within the crown of the host tree in two sites of Osan and Siheung in Korea from May to August, 2007. Density of LGM was investigated based on the number of larvae per leaf. Two generations of LGM were observed in Siheung site whereas three generations in Osan site during the present study. The result indicated that LGM had at maximum three generations per year. The density of LGM in Osan was higher in the upper crown of the host trees than middle or lower part. In Siheung, LGMs were distributed more on the exterior of the lower crown than the interior. The average number of larvae per gall was $3.3{\pm}0.1$ and $2.8{\pm}0.1$ individuals per leaf in Osan and Siheung, respectively.

A Study on the Costume of the Gods in the Ancient Roman Myths (고대 로마 신화에 등장한 신들의 복식 연구)

  • 임상임;추미경
    • Journal of the Korean Society of Clothing and Textiles
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    • v.25 no.5
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    • pp.945-956
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    • 2001
  • The costume for gods in the Ancient Roman myth was studied by examining in the embossed-carving, sculptures, mural-painting and various documents of the period. The clothes item, hairstyle, symbol & ornaments and shoes of the gods in the Roman myths were analyzed to understand the formative process in the religious costumes, and results are as follows. First, the costumes for male gods are the same as those for ordinary men lived in ages, including toga, paludamentum, tebenna, tunica. The costumes for female gods are also the same as those for ordinary women lived in ages, including stola, palla, tunica. Second, the hairstyle of male gods is short curled-hair, twisty roll-up hair and braid long-hair due to the influence of Etrurian in the early days. Another hairstyle is appeared in form of the laurelled-crown. The hairstyle of female gods is curled long-hair, chignon style and braid roll-up hair decorated with hairband. Third, the symbol & ornaments which represent the responsible possession of male gods, are appeared in beard, a stick of the message, arrow-case, offering-dish, antlered-glass, shield, spear-handle, as the superhuman forms, such as the lightning shape. For female gods they are is appeared plastron, a stick of the message, flower. some female gods wear necklace, foot-ring, bracelet. Fourth, male gods wear shoes in forms of sandal, buskin, boots, but all female gods are in barefoot. It could be explained by the fact that a man-centered society in the ancient roman is reflected in the world of gods. As mentioned, Gods costume in Roman myths was very similar to or nothing different from the ordinary peoples in Rome. However, they used corps, sacrifices or sepcific symbols depending on the fields that they were responsible for in order to be distinguished from the ordinary people. This is the result from the peoples expression that they should keep a close relationship with Gods hoping to be protected, and rely on them under whatever circumstances.

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