• Title/Summary/Keyword: 냉간압연

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Fabrication of AA4343 Alloys by Twin Roll Casting and their Properties (쌍롤 박판주조법에 의한 AA4343 합금의 제조 및 특성)

  • Euh, Kwang-Jun;Kim, Min-Gyun;Baek, Eun-Ji;Kim, Hyoung-Wook
    • Proceedings of the KAIS Fall Conference
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    • 2011.12b
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    • pp.646-648
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    • 2011
  • 본 논문에서는 쌍롤 박판주조(Twin Roll Casting, TRC)법을 이용하여 AA4343 합금을 제작하였다. 주조시 롤 간격을 조절하여 냉각속도를 달리하였으며 인고트 주조(Ingot Casting, IC)법을 이용하여 제조된 합금과의 미세조직학적 차이와 이에 따른 물성 변화를 고찰하였다. TRC 및 IC로 제조된 합금을 냉간압연하였으며 압연 건전성을 평가하였다. 한편, 냉각속도별로 상이한 미세조직을 구현할 수 있는 스텝몰드(Step Mold Casting, SMC)법을 이용하여 제조된 합금의 냉각속도에 따른 미세조직 및 경도 차이를 조사하여 상대 비교하였다. 냉각속도가 빠를수록 주조 셀조직의 크기 및 공정 Si 입자의 크기가 감소하였으며 이로 인하여 경도가 증가되는 효과를 나타내었다. 주조시 생성된 공정 Si 입자의 크기는 압연에 의하여 그 크기의 변화가 거의 없었으며 열분석 결과 액상선 온도의 변화가 일부 발생하나 큰 차이가 없었다.

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Ti 판재 및 Ti/Al 적층재의 기계적 특성에 미치는 냉간 압연공정의 영향

  • Kim, Jong-Myeong;Kim, Mok-Sun
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2012.05a
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    • pp.104.1-104.1
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    • 2012
  • 타이타늄(Ti)은 비강도가 높고, 내식성이 우수하여 항공기, 자동차 및 선박과 같은 수송기기의 소재로 사용되고 있다. 이러한 특성을 가진 타이타늄을 이종소재와 결합하여 더 우수한 기계적 특성을 얻을 수 있다면, 그 응용범위를 확대할 수 있을 것이다. 본 연구에서는 타이타늄과 알루미늄(Al) 판재를 적층한 후, 열간압연을 통해 타이타늄/알루미늄 적층재를 제조하였다. 이와 같은 적층재를 다양한 압하율로 냉간 압연한 후 미세조직을 관찰하였으며, 인장시험을 통해 기계적 특성을 조사하였다. 아울러 타이타늄 판재만으로도 유사한 실험을 실시하여 기계적 특성을 적층재와 비교 평가하였다.

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A Study on Development of Setup Model for Thickness Control in Tandem Cold Rolling Mill (연속냉간압연의 두께제어 모델 개발에 관한 연구)

  • 손준식;김일수;권욱현;최승갑;박철재;이덕만
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.10 no.5
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    • pp.96-103
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    • 2001
  • The quality requirements for thickness accuracy in cold rolling continue to become more stringent, particularly in response to exacting design specification from automotive customers. One of the major impacts from the tighter tolerance level is more unusable product on the head end and tail end of tandem mill coils when the mill is in transition to or from steady state rolling condition. A strip thickness control system for a tandem cold steel rolling mills is composed with blocked non-interacting controller and controllers for strip thickness and tension control of each rolling stands. An intelligent mathematical model included an elastic deformation of strip has been developed and applied to the field in order to predict the rolling force. The simulated results showed that the effect of elastic recovery should be included the model, even if the effect of elastic compression was not important.

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Roll Wccentricity Control for Cold Strip Rolling Processes (냉간압연 공정에의 편심제어)

  • 백기남;류석환
    • 제어로봇시스템학회:학술대회논문집
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    • 1991.10a
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    • pp.243-247
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    • 1991
  • A roll eccentricity controller for a tandem cold rolling process is designed to attenuate the outlet thickness deviation due to roll eccentricity. In order to design the controller, the excess stability margin is maximized by solving a standard H.inf. optimization problem under the requirement that ensure disturbance rejection for a class of disturbance. Robust performance of the proposed controller is checked by a computer simulation.

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A study on carbonization on the surface of steel sheet during the BAF annealing process (BAF 소둔공정에서 탄화 현상에 관한 연구)

  • Lee, Jong-Lyul
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.7
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    • pp.42-49
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    • 2018
  • In steel industries, cold-rolled sheet manufacturing is one of the links between the front and rear important industries for national competitiveness and high value-added production. In particular, in small and medium-sized enterprises, one of the major problems is the carbonization phenomenon of the steel sheet during the annealing process. Carbonization occurring on the surface of the coil help reduce steel production. After conducting various experiments to identify the cause of carbonization on the surface of a cold-rolled steel, the following results were obtained: (1) An analysis of the rolling oil, which is used in the field, revealed it to contain approximately 40 ppm carbonized material. (2) A comparison of the thermal denaturation characteristics of the fresh rolling oil and using rolling oil by FT-IR analysis showed that thermal denaturation had occurred, as shown by the significant decrease in the relative intensity of the 2900 and $1750cm^{-1}$ peaks. (3) The thermal decomposition of the rolling oil took place for the rolling oil at approximately $220^{\circ}C$. Furthermore, annealing experiments at $200^{\circ}C$ showed that the carbonization phenomenon of the sample was not observed. On the other hand, carbonization was observed at temperatures higher than $240^{\circ}C$.

Design of Rolling Pass Schedule in Copper Thin Foil Cold Rolling According to Roll Crown of 6 High Mill (6단 압연롤 크라운을 고려한 동극박 냉간 압연 패스스케줄 설계)

  • Lee, Sang-Ho;Ok, Soon-Young;Hwang, In-Youb;Hwang, Won-Jea;Kim, Byung-Min
    • Journal of the Korean Society for Precision Engineering
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    • v.25 no.11
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    • pp.66-72
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    • 2008
  • During the plate and foil cold rolling process, considerable values of the force of material pressure on the tool occur. These pressures cause the elastic deformation of the roll, thus changing the shape of the deformation legion. Rolled copper foils should be characterized by a good quality and light dimensional tolerances. Because of automation that is commonly implemented in flat product rolling mills, these products should meet the requirements of tightened tolerances, particularly strip thickness, and feature the greatest possible flatness. The shape of the roll gap is influenced by the elastic deformation of rolls parts of the rolling process affecter of the pressure force. However, to control roll deformation should be difficult. Because the foil thickness is very thin and the permissible deviations in the thickness of foil are small. In this paper, FE-simulation of roll deformation in thin foil cold roiling process is presented.

Improving the Corrosion Resistance of Cold-Rolled Carbon Steel by Treatment with a Hybrid Organic/Inorganic Coating Solution (유/무기 하이브리드 코팅액에 의한 냉간압연강판의 내식특성)

  • Kim, Jung-Ryang;Choi, Chang-Min;Nam, Ki-Woo
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.36 no.4
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    • pp.405-412
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    • 2012
  • In the past, a very popular way to reduce the corrosion rate of zinc was the use of chemical conversion layers based on $Cr^{+6}$. However, the use of chromium salts is now restricted because of environmental protection legislation. Previous research investigated the optimum corrosion resistance of galvanized steel treated with an organic/inorganic solution containing Si. The result showed that the optimum corrosion resistance occurred by heat treatment of $190^{\circ}C$ in 5 min. In this study, one organic and three hybrid organic/inorganic coating solutions were applied to cold-rolled (CR) carbon steel. The coatings were then evaluated for corrosion resistance under a salt spray test. The coating solutions examined in this study consisted of urethane-only, urethane-Si, urethane-Si-Ti, and urethane-Si-Ti-epoxy. The results of the 7 h salt spray test showed that the urethane-Si-Ti and urethane-Si-Ti-epoxy coating solutions had superior corrosion resistance on CR steel.