• Title/Summary/Keyword: rolling

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Effect of Silver Particle Introduction on Rolling Friction (구름거동에 미치는 은 입자 투여의 영향에 대한 실험적 고찰)

  • 양승호;공호성;윤의성;김대은
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2001.06a
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    • pp.105-113
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    • 2001
  • The effect of silver particle introduction on the rolling friction of AISI 52100 steel pairs has been investigated. Experiments were performed in dry conditions using a thrust bearing-type rolling test rig at a load range of 12 - 960 N and a sliding velocity range of 8 - 785 mm/sec with pure(99.99%) silver particles. Results showed that the introduced silver particles formed transfer layer, which protected virgin bearing surfaces and resulted in low rolling friction. By changing the quantity of silver particles, transitions in the rolling friction wear found. Results also showed that the variations in normal load and rolling speed also affected the rolling friction behavior. Analyses using SEM and EPMA showed that tile formation of transfer layer was mainly governed by the silver particle quantity, normal load and rolling speed, and this resulted in the different behavior of rolling friction. In this study, it was found that the low and stable rolling friction was resulted from the shakedown phenomena occurred at the silver transfer layer.

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FEA of Copper Tube Rolling Process Using the Planetary Rolling Mill (유성압연기를 사용한 동관 압연공정의 유한요소해석)

  • Lee, Jung-Kil;Han, Ki-Beom;Kim, Kwan-Woo;Choe, Jong-Woong;Kim, Jae-Hun;Cho, Hae-Yong
    • Journal of Advanced Marine Engineering and Technology
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    • v.34 no.2
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    • pp.303-309
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    • 2010
  • Copper tube rolling process using the planetary rolling mill has been studied by using finite element method. This rolling is process that makes copper tube by three-roll with mannesmann method. Also, rolling process has started from the cold working and finished to the hot working. This rolling process has more advantage that make reduction of process and cost than existing extrusion. This process includes various and complex process parameters. Each of the process parameters affects forming result. Therefore, all of the process parameters should be considered in copper tube rolling. Rolling process for copper tube was successfully simulated and it should be useful to determine optimal rolling condition.

Effects of Rolling Numbers and Feeds on Surface Deformation in Surface Rolling of Cast Iron (주철의 표면로울링에서 이송량과 로울링 회수에 따른 변화 연구)

  • Yuck, Kweng-Su;Lee, Yong-Chul;Kwak, Soo-Heon
    • Journal of the Korean Society for Precision Engineering
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    • v.6 no.3
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    • pp.68-77
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    • 1989
  • The surface rolling for cylindrical surface of a grey cast iron was carried out using a lathe with a simple newly-designed tool system. A surface rolling tool used was steel ball whose diameter was 3/8 inch (9.525mm) The effects of rolling feeds and number of rolling on surface rolling were investigated. The contact pressure between ball and workpiece which was considered as Hertz's contact problem was examined and the track of motion of a ball on the cylindrical surface of a work- piece was measured according to the rolling feed. The results obtained were as follows; 1. The roughness of the machined surface which was originally 5.3 .approx. 28 umRz decreased to 1.2 .approx. 5 umRz according to rolling feeds and numbers of rolling. 2. The hardness increased from Hv 260 to Hv 290 .approx. 310 through 2 .approx. 4 rollings according to the roughness of machined surfaces. 3. The reduction of diameter was found to be proportional to the variations of roughness of previous machined surfaces. About 60% to 90% of reduction in diameter was made during the first rolling process. 4. An equation relating the reduction of diameter and the variation of surface roughness after surface rolling was presented using a geometric surface model. 5. An equation for the calculation of dynamic contact area between pressure ball and workpiece according to the rolling feed was presented.

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Deformation Behavior & Rolling Effect on the Hot Rolling of High Nitrogen Stainless Steel (고질소강의 열간압연시 변형거동 및 압연효과)

  • Kim, Y.D.;Kim, D.K.;Lee, J.W.;Bae, W.B.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2008.10a
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    • pp.329-332
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    • 2008
  • Nowadays, It is required human body-friendly, good mechanical properties, and economical efficiency material, simultaneously. The material to meet above requirement condition rear up high nitrogen stainless steel(HNS). However, HNS have a lot of problem such as poor workability, hot crack sensitivity. So, It is needed the condition of plastic working to overcome above many problem. In this study, VIM ingot with 100kg was made by pressurized vacuum induction melting. And then, The slab perform for hot rolling was prepared by open-die forging. Hot rolling process was performed by computer simulation according to change of height reduction, rolling temperature, heating numbers, rolling pass and so forth. The results of analysis were investigated between analysis and lab-scale rolling product.

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A Study on Rolling Mill Dynamics Model and Automatic Gauge Control System

  • Kim, Tae-Young;Kwon, Dae-Hyun;Choi, Won-Ho
    • 제어로봇시스템학회:학술대회논문집
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    • 2004.08a
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    • pp.120-125
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    • 2004
  • In the rolling of steel or non-steel metal the most important quality aspect are thickness and flatness. In thickness, there are two important factors. One of them is getting close with accurate goal, nominal gauge, the other is minimize gauge bandwidth, the variation in gauge. In this thesis, we proposed the fuzzy model AGC to minimize gauge variation along the length, developed the rolling mill dynamic model using the math mode of the rolling mill process and the rolling model related with the variety character of the rolling material. We compared the gauge control efficiency of fuzzy model AGC and PI mass flow AGC. We have got a simulation result, that the exit gauge variation of PI mass flow AGC was 2 micron and fuzzy model AGC was 1.2 micron at 1200mpm of rolling speed when each controller was rolling 5 micron of material that is the entry gauge variation.

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Evolution of Strain States and Textures During Rolling with Various Conditions (압연조건에 따른 변형률 상태의 변화와 집합조직의 형성)

  • Kang, H.G;Huh, M.Y
    • Transactions of Materials Processing
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    • v.15 no.7 s.88
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    • pp.479-484
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    • 2006
  • The evolution of strain states and textures during rolling with various conditions was investigated by finite element method (FEM) simulations and measurements of rolling textures. Symmetrical rolling with a high friction gives rise to a strong variation of shear strains in rolled sample leading to the formation of texture gradients throughout the thickness layers. A small variation of shear strains during rolling with a well lubrication condition leads to the formation of a fairly homogeneous rolling texture throughout the sheet thickness. During asymmetrical rolling, a proper control of rolling parameters provides the evolution of a fairly homogeneous shear texture throughout the whole sheet thickness.

Effect of Rolling Speed on the Exit Cross Sectional Shape in Rod Rolling Process

  • Lee, Young-Seog
    • International Journal of Precision Engineering and Manufacturing
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    • v.8 no.1
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    • pp.27-31
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    • 2007
  • A rolling speed dependent spread model is proposed for predicting the exit cross sectional shape in oval-round (or round-oval) pass rod rolling process when the rolling speed is very high. The effect of rolling speed on the exit cross sectional shape is measured by performing a four-pass continuous high speed (${\sim}80m/s$) rod rolling test and is described in terms of the spread correction parameter. The validity of the model is examined by applying it to rod rolling process at POSCO No.3 Rod Mill. The cross sectional shapes of workpiece predicted by the proposed model coupled with the surface profile prediction $method^{6}$ are in good agreement with those obtained experimentally.

Effect of Roll Gap Geometry on the Evolution of Strain States and Textures during Asymmetrical Rolling in AA1050 (AA1050 판재의 비대칭 압연 시 변형률 상태와 집합조직 발달에 미치는 압연변형 형상의 영향)

  • Kang, H.G.;Nah, J.J.;Huh, M.Y.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2006.05a
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    • pp.219-221
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    • 2006
  • Asymmetrical rolling was performed by rolling AA 1050 sheets with different velocities of upper and lower rolls. In order to study the effect of roll gap geometry on the evolution of strain states and textures during asymmetrical rolling, the reduction per rolling pass was varied. After asymmetrical rolling, the outer thickness layers depicted shear textures and the center thickness layers displayed a random texture. With decreasing reduction per an asymmetrical rolling pass, the thickness layers depicting shear textures increases. The strain states associated with asymmetrical rolling were investigated by simulations with the finite element method (FEM).

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Development of a framework for engineering RAMS into rolling stock through life cycle in the operator perspective (철도차량의 개발 및 운용을 위한 RAMS 관리 시스템 개발)

  • Park, Mun-Gyu;An, Min
    • Proceedings of the KSR Conference
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    • 2010.06a
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    • pp.2179-2194
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    • 2010
  • RAMS is becoming increasingly important in the decision making process for the rolling stock projects in order to improve competitiveness by reducing system life cycle cost while improving reliability, availability, maintainability and safety. In order to apply and manage RAMS of rolling stock systems effectively in the operator perspective, it is essential to integrate and control RAMS systematically from the early stage of rolling stock projects. RAMS management is to implement a RAMS system into rolling stock projects in terms of a rolling stock operator, which presents the strategic directions of RAMS policy, objectives, requirements, control, analysis, measurement and improvement throughout life cycle of rolling stock projects. This article presents a new framework of RAMS management that provides an effective and efficient way for managing RAMS in rolling stock systems in the railway industry.

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Effect of Silver Particle Introduction on Rolling Friction (구름거동에 미치는 은 입자 투여의 영향에 대한 실험적 고찰)

  • 양승호;공호성;윤의성;김대은
    • Tribology and Lubricants
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    • v.17 no.6
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    • pp.417-426
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    • 2001
  • The effect of silver particle introduction on the rolling friction of AISI 52100 steel pairs has been investigated. Experiments ware performed in dry conditions using a thrust bearing-type rolling test rig at a load range of 12-960 N and a sliding velocity range of 8-785 mm/sec with pure (99.99%) silver particles. Results showed that introduced silver particles formed transfer layers, which protected the virgin bearing surfaces and resulted in the low lolling friction. By changing the quantity of silver particles, transitions in the rolling friction were found. Results also showed that the variations in normal load and rolling speed also affected the rolling friction behavior. Analyses of SEM and EPMA showed that the formation the transfer layer was mainly governed by the silver particle quantity, normal load and rolling speed, and this resulted in the different behavior of rolling friction. In this study, it was found that the low and stable rolling friction was resulted from the, shakedown phenomena occurred at the silver transfer layer.