• Title, Summary, Keyword: final rolling process

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Characteristic Analysis and Selection of Process Parameters in Direct Rolling Processes (직접압연공정의 특성해석 및 공정변수 선정)

  • 박영준;조형석;이원호;강태욱
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.384-388
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    • 1997
  • Recently,direct rolling process has been drawing increasing interests because production cost be greatly reduced by eliminating subsequent hot rolling processes. Such a process has been characterized to prosuce thin steel strip (thickness 1~5mm) directly from molten metal and to skip over the conventional hot rolling processes. However, since there are several process parameters, which affect the quality of product,and their relationship between the parametersare very complex,it is therefore very difficult to realize the process design and the quality control. To overcome these difficulties quantitative relationship between the parameters are investigated through a numerical analysis. Form these results, it is found that solidification final point is the most important paramter which is critical to quality of the strip. Also,the multiple regression model is obtianed to determine their relationship from the solidification final point and roll separating force which can be easily estimated

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Mechanical Property Variations of the Strip in the Skin Pass Process after Hot Rolling (열연 강판의 정정공정에 따른 재질변화 예측기술)

  • Lee, J.H.;Kim, H.J.;Kim, J.M.;Lee, J.K.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • pp.211-214
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    • 2008
  • The Mechanical properties of steel in hot strip mill were associated with the various rolling conditions such as alloy composition, plastic deformation, cooling history and so on. After coiling process of strip which is the end of hot rolling process, the coil can be the final product or can be applied by another process, that is, cold rolling or skin pass rolling with the additional changes of mechanical properties. Skin pass rolling process with the small reduction affects the mechanical properties of the strip. Because many kinds of hot strips are delivered to the customers after the skin pass process, it is important for us to know the skin pass effects for the mechanical properties of the hot rolling strip. In this study, the variations of mechanical properties of the strip after the skin pass rolling will be discussed. Then, the mathematical model will be proposed for the prediction of mechanical properties of the final products with the comparison between measured and calculated values.

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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.

Determination of the process variables for quality monitoring in direct rolling processes (직접압연 공정에서 품질계측을 위한 공정변수의 선정)

  • 배세철;박영준;조형석
    • 제어로봇시스템학회:학술대회논문집
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    • pp.1364-1367
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    • 1996
  • Recently, direct rolling process, called as strip casting process, has been interested in to save production cost by reducing forming processes. In direct rolling process, since a steel strip of thickness 1-5(mm) can be produced directly from molten metal, it can eliminate secondary hot rolling process. On the other hand, since many process variables are existed in this process and relation of these variables is very complex, it is difficult to realize the process design and the quality control. In this paper, as first step to overcome above difficulties, the quantitative relationship of the process variables affected to quality of the strip has been carried out through the numerical analysis. Also, we determined the process variable to monitor the quality in the direct rolling process. As a result, we show that the solidification final point, called as Nip point, was related directly to quality of the strip.

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Magnetic Properties of Permalloy(PB, PC) Strips Fabricated by Powder Rolling Process (분말 압연에 의해 제조된 퍼말로이(PB, PC)의 자성 특성)

  • 이동원
    • Journal of Korean Powder Metallurgy Institute
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    • v.3 no.1
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    • pp.13-24
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    • 1996
  • Two grades of Permalloy strips, Fe-45Ni(PB) and Fe-78Ni-4Mo-5Cu(PC) were fabricated by powder rolling process from elemental powder mixtures. The roll compacted green strips were sintered, homogenized, cold rolled with or without an intermediate annealing and finally heat treated to measure magnetic properties. For a given thickness reduction, rolling with an intermediate annealing was found more effective to achieve a full densification with no visible micropores and also to obtain better magnetic properties. Increasing the final rolling reduction also produced a marked improvement of the magnetic properties whereas the cooling rate during the final heat treatment has little effect in both grades. Addition of a small amount, 0.4% Mn slightly degraded the properties. As an overall, The PM strips produced via powder rolling yielded the similar soft magnetic properties to the corresponding commercial grades produced via wrought processing.

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Ring-Rolling Design of a Large-Scale Ti-6Al-4V alloy (대형 Ti-6Al-4V 합금의 Ring-Rolling 공정설계)

  • Yeom, J.T.;Jung, E.J.;Kim, J.H.;Lee, D.G.;Park, N.K.;Choi, S.S.;Lee, C.S.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • pp.373-376
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    • 2006
  • The ring rolling design for a large-scale Ti-6Al-4V alloy ring was performed with a calculation method and FEM simulation. The ring rolling design includes geometry design and optimization of process variables. The calculation method was to determine geometry design such as initial billet and blank size, and final rolled ring shape. A commercial FEM code, SHAPE was used to simulate the effect of process variables in ring rolling on the distribution of the internal state variables such as strain, strain rate and temperature. In order to predict the forming defects during ring rolling, the process-map approach based on Ziegler's instability criterion was used with FEM simulation. Finally, an optimum process design to obtain sound Ti-6Al-4V rings without forming defects was suggested through combined approach of Ziegler's instability map and FEM simulation results.

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A Study on Profile Ring Rolling Process of Titanium Alloy (타이타늄합금 형상 링 압연공정 연구)

  • Yeom, J.T.;Kim, J.H.;Lee, D.G.;Park, N.K.;Choi, S.S.;Lee, C.S.
    • Transactions of Materials Processing
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    • v.16 no.4
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    • pp.223-228
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    • 2007
  • The profile ring rolling process of Ti-6Al-4V alloy was investigated by finite element(FE) simulation and experimental analysis. The process design of the profile ring rolling includes geometry design and optimization of process variables. The geometry design such as initial billet and blank sizes, and final rolled ring shape was carried out with the calculation method based on the uniform deformation concept between the wall thickness and ring height. FEM simulation was used to calculate the state variables such as strain, strain rate and temperature and to predict the formation of forming defects during ring rolling process. Finally, the mechanical properties of profiled Ti-6Al-4V alloy ring product were analyzed with the evolution of microstructures during the ring rolling process.

Process Design for Profile Ring Rolling of Ti-6Al-4V Alloy (Ti-6Al-4V합금의 형상 링 압연 공정설계)

  • Yeom, J.T.;Kim, J.H.;Lee, D.G.;Park, N.K.;Choi, S.S.;Lee, C.S.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • pp.357-360
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    • 2007
  • The profile ring rolling process of Ti-6Al-4V alloy was designed by finite element(FE) simulation and experimental analysis. The design includes geometry design and optimization of process variables. The geometry design such as initial billet and blank sizes, and final rolled ring shape was carried out with the calculation method based on the uniform deformation concept between the wall thickness and ring height. FEM simulation was used to calculate the state variables such as strain, strain rate and temperature and to predict the formation of forming defects during ring rolling process. Finally, the mechanical properties of profiled Ti-6Al-4V alloy ring product were analyzed with the evolution of microstructures during the ring rolling process.

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Plastic characteristic analysis of width reduction process in hot roughing mill (열간조압연 공정에서의 폭 압하 공정시 슬래브의 변형 특성)

  • Heo, Su-Jin;Lee, Sang-Ho;Byun, Sang-Min;Park, Hae-Do;Lee, Jong-Bin;Kim, Byung-Min
    • Proceedings of the KSME Conference
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    • pp.544-548
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    • 2007
  • In general, final width of hot strip should be accomplished in this stage because width reduction of strip hardly appears during typical finishing mill. However, it is difficult to control the width of strip in the roughing mill process as the horizontal rolling of strip is subsequently performed after the vertical rolling. It is therefore important to obtain the deformation rolling direction on strip width to minimize the width spread of strip during horizontal rolling after vertical rolling. Generally there is Sizing press type and Edger-roll type. The width reduction process in sizing press has small amount of width spread compared with the edger. However, productivity by the sizing press process is much lower than those of the edger. In this study, sizing press and Edger-roll process parameters in a sheet rolling mill were set at specified values and the effect of the change in these parameters on product quality and process performance were evaluated.

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Finite Element Analysis of Manufacturing Process of a 12 Point Flange Head Bolt with Emphasis on Thread Rolling Process (나사전조공정을 중시한 12각플랜지볼트의 나사제조공정의 유한요소해석)

  • Jang, S.J.;Lee, M.C.;Shim, S.H.;Son, Y.H.;Yoon, D.J.;Joun, M.S.
    • Transactions of Materials Processing
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    • v.19 no.4
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    • pp.248-252
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    • 2010
  • In this paper, three-dimensional finite element analysis of thread rolling process of a 12 point flange head bolt is conducted using a rigid-plastic finite element method based metal forming simulator AFDEX 3D. A whole sequence of cold forming processes of a long shaft bolt composed of four forging stages and final thread rolling process is simulated to reveal the mechanism of thread formation. A mesh density control function is applied near the major plastic deformation region to achieve computational efficiency. It has been shown both numerically and experimentally that longitudinal lengthening or shortening is negligible in thread rolling.