• Title/Summary/Keyword: Rolling Up

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The Study on Setting up KTX-II's RAM Goals for Requirement Train-set (고속차량(KTX-II) RAM 목표값 설정을 통한 소요량 연구)

  • Cha, Jae-Hwan;Chung, In-Soo;Kim, Jong-Woon;Yu, Yang-Ha
    • Proceedings of the KSR Conference
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    • 2009.05b
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    • pp.191-198
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    • 2009
  • There are almost no studies on verification of requirements for high speed rolling stocks by means of RAM goals and on setting RAM goals by means of verification on practical reliability, availability and maintainability for high speed rolling stocks though they are covered in specification of an order that RAM goals asked of rolling stocks are shown for gaining high quality of them and availability when they are in operation. This study is for estimating number of high speed train-sets that would be supplementarily placed an order through verification of RAM goals of a project for the introduction of KTX-II 100 cars. It verify that optimized requirements for high speed rolling stocks by relatively comparison with between requirements for train-sets through setting RAM goals and requirements for train-sets through analysis of prospects for management balance with high speed rolling stocks.

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Track Irregularity Inspection Method for Commercial Vehicle (영업차량에서의 궤도비틀림 검측 방안 연구)

  • Lee Chan-Woo;Choi Eun-Young
    • Proceedings of the KSR Conference
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    • 2003.05a
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    • pp.768-773
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    • 2003
  • The inspection of track irregularity, which is the most important index for the evaluation of the dynamic safety of the rolling stock, is performed by setting up the testing train set. The self-diagnosis for the various rolling stocks and railways can be obtained if it is possible to take the simultaneous inspection of track irregularity for the commercial vehicle while it is running and to build up a dynamic safety evaluation system. It is expected to have some good effects, such as preventing accident with the low dynamic safety, cutting cost for the testing train set and evaluating the exact influence on the rolling stock and railway. In this study, innertial measuring method, which allows us to directly measure the track irregularity from the commercial vehicle, will be considered and some overseas cases will be explored as well.

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Prediction of Ski-Effect in Plate Rolling Process using Neural Network Algorithm (후판 압연에서 신경망 알고리즘을 이용한 스키 예측)

  • Park, J.S.;Na, D.H.;Jung, S.H.;Hur, S.M.;Choi, H.J.;Lee, Y.S.
    • Transactions of Materials Processing
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    • v.22 no.5
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    • pp.250-257
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    • 2013
  • A series of finite element analyses of the rolling process were performed and a neural network algorithm was employed to calculate the amount of ski-effect for an arbitrary thickness of incoming material in the roll gap. Pilot hot plate rolling tests were also conducted to verify the usefulness of the finite element analyzes conducted in this study. In these experiments, plates with thicknesses varying from 25 to 65 mm were tested. In addition, a number of rolling reductions of up to 31% were examined. Finally, a number of circumferential upper and lower rolls were investigated. Experimental validations demonstrated that the neural network algorithm predicted the proper amount of ski when rolling conditions(material thickness, reduction ratio, roll velocity differential) changed arbitrarily.

Study on Setting up the Quantitative RAM Goals for Rolling Stocks (철도차량 정량적 신뢰성.가용성.유지보수성(RAM) 목표값 설정에 관한 연구)

  • Chung, In-Soo;Lee, Kang-Won;Kim, Jong-Woon
    • Journal of the Korean Society for Railway
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    • v.11 no.4
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    • pp.390-397
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    • 2008
  • Quantitative RAM (Reliability, Availability, Maintainability) is the one of the important indicator that shows the quality of rolling stock. It is usually required in the domestic and abroad purchase specification of rolling stock. And achieving and demonstrating the quantitative RAM goals is also required. In this study, the method to set up these goals will be proposed in the aspects of service and logistic reliability, operational, achievement or inherent availability and maintainability. And we apply this proposed method to the real operation data.

Development of set-up model for elongation control in steel skin pass mill (강판의 연신율제어를 위한 Set-Up 모델 개발)

  • 이원호;이규택;류율리
    • 제어로봇시스템학회:학술대회논문집
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    • 2000.10a
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    • pp.317-317
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    • 2000
  • The mathematical set-up model was developed to reduce the mechanical property deviation in annealed and slightly rolled steel strip. The mechanical peculiarities of temper rolling process, such as high friction value and non-circular contact arc, Low reduction and non-negligible entry and exit elastic zones as well as central restricted deformation zone are all taken into account. The deformation of work rolls is calculated with the influence function method and arbitrary contact arc shape is permitted. The strip deformation is modeled by slab method and the entry and exit elastic deformation zones are included. The restricted deformation Bone near the neutral point is also considered. It was revealed that the new model has better accuracy than present regression model by statistical analysis with actual mill rolling data.

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Effects of Static Contact Angle and Roughness on Rolling Resistance of Droplet (액적의 구름저항에 대한 정접촉각 및 거칠기의 영향)

  • Cho, Won Kyoung;Cho, Sang Uk;Kim, Doo-In;Kim, Dae-Up;Jeong, Myung Yung
    • Journal of the Microelectronics and Packaging Society
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    • v.23 no.1
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    • pp.23-28
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    • 2016
  • In this study, the effects of the contact angle (CA) and contact angle hyteresis (CAH) of planar and nano-patterned surfaces on rolling resistance of water droplet were studied. Based on the investigation on the CAH of water droplet on surfaces with various static wettability, it was found that the rolling resistance coefficient of water droplet is highly influenced by the surface pattern as well as CAH. The observed results suggest that the optimal surface patterns should be designed in order to minimize the rolling resistance of water droplet for the practical applications where superhydrophocitiy is required.

The Effect on the Thickness Variation According to Rolling Condition and Temperature Drop At Top-end in Plate Rolling (후판 압연 시 공정변수 및 선단부의 온도저하가 두께편차에 미치는 영향)

  • Yim, H.S.;Joo, B.D.;Lee, H.K.;Seo, J.H.;Moon, Y.H.
    • Journal of the Korean Society for Heat Treatment
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    • v.22 no.1
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    • pp.16-22
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    • 2009
  • The rolling process is an efficient and economical approach for the manufacturing of plate metals. In the rolling process, the temperature variation is very critical for plate thickness accuracy. The main cause of thickness variation in hot plate mills is the non-uniform temperature distribution along the length of the slab. Also the exit plate thickness is mainly affected by the rolling conditions such as mill modulus, plate thickness and plate width. Hence the thickness variation in top-end is also dependent on these factors. Therefore this study has concentrated on determining the correct amounts of thickness variation due to top-end temperature drop and process parameters.

Modeling Method for the Force and Deformation Curve of Energy Absorbing Structures to Consider Initial Collapse Behaviour in Train Crash (열차 충돌에너지 흡수구조의 초기붕괴특성을 고려하기 위한 하중-변형 곡선 모델링 방법)

  • Kim, Joon-Wo;Koo, Jeong-Seo;Lim, Jong-Soon
    • Transactions of the Korean Society of Automotive Engineers
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    • v.18 no.3
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    • pp.116-126
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    • 2010
  • The Korean rolling stock safety regulation stipulates that the collision deceleration of a car body should be maintained under average 5g and maximum 7.5g during train collisions. One-dimensional dynamic model of a full rake train, which is made up of nonlinear springs/bars-dampers-masses, is often used to estimate the collision decelerations of car bodies in a basic design stage. By the way, the previous studies have often used some average force-deformation curve for energy absorbing structures in rolling stock. Through this study, we intended to analyse how much the collision deceleration levels are influenced by the initial peak force modeling in the one-dimensional force-deformation curve. The numerical results of the one-dimensional dynamic model for the Korean High-Speed Train show that the initial peak force modeling gives significant effect on the collision deceleration levels. Therefore the peak force modeling of the force-deformation curve should be considered in one-dimensional dynamic model of a full rake train to evaluate the article 16 of the domestic rolling stock safety regulations.

Mechanical Properties and Texture after Thermomechanical Treatment of Al/Al2O3 Composite Fabricated by Powder-in Sheath Rolling Method (분말피복압연법에 의해 제조된 Al/Al2O3 복합재료의 가공열처리후의 기계적 성질 및 집합조직)

  • 이성희;이충효
    • Journal of Powder Materials
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    • v.10 no.4
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    • pp.235-240
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    • 2003
  • The $Al/Al_2O_3$ composites fabricated by powder in sheath rolling method were cold-rolled by 50% reduction and annealed for 1.8 ks at various temperatures ranging from 200 to 50$0^{\circ}C$, for improvement of the mechanical properties. The mechanical properties and texture of the composites after rolling and annealing were investigated. The tensile strength of the composites increased significantly due to work hardening after cold rolling, however it decreased due to restoration after annealing. The strength of the composites was improved by thermo mechanical treatment. On the other hand, the texture evolution with annealing temperatures wa,i different between the unreinforced material and the composites. The unreinforced material showed a deformation (rolling) texture of which main component is {112}<111> at annealing temperatures up to 30$0^{\circ}C$. However, the composites have already exhibited a recrystallization texture of which main component is {001}<100> after annealing at 20$0^{\circ}C$. This proves that the critical temperature for recrystailization is lower in the composites than in the unreinforced ones.

Effect of Repetitive Cold Rolling and Annealing on the Superplasticity of Fe-10Mn-3.5Si Alloy (Fe-10Mn-3.5Si 합금의 초소성에 미치는 반복 냉연 및 소둔의 영향)

  • Jeong, Hyun-Bin;Choi, Seok-Won;Lee, Young-Kook
    • Journal of the Korean Society for Heat Treatment
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    • v.35 no.4
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    • pp.211-219
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    • 2022
  • It is known that superplastic materials with ultrafine grains have high elongation mainly due to grain boundary sliding. Therefore, in the present study we examined the influence of grain refinement, caused by a repetitive cold rolling and annealing process, on both superplastic elongation and superplastic deformation mechanism. The cold rolling and annealing process was repetitively applied up to 4 times using Fe-10Mn-3.5Si alloy. High-temperature tensile tests were conducted at 763 K with an initial strain rate of 1 × 10-3 s-1 using the specimens. The superplastic elongation increased with the number of the repetitive cold rolling and annealing process; in particular, the 4 cycled specimen exhibited the highest elongation of 372%. The primary deformation mechanism of all specimens was grain boundary sliding between recrystallized α-ferrite and reverted γ-austenite grains. The main reason for the increase in elongation with the number of the repetitive cold rolling and annealing process was the increase in fractions of fine recrystallized α-ferrite and reverted γ-austenite grains, which undergo grain boundary sliding.