• Journal of Mechanical Science and Technology
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• 제15권2호
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• pp.225-231
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• 2001

A mathematical model for the analysis of roll gap phenomena in the strip temper rolling process is described. A new approach to solve the roll indentation and diverging problem in modeling of severe temper rolling cases is obtained by adopting the preliminary displacement principle of two contacted rough bodies to describe the friction behavior in the roll gap. The mechanical peculiarities of the temper rolling process, such as a high friction value with high roughness rolls and a non-circular contact arc, low reduction and non-negligible entry and exit elastic zones as well as central preliminary displacement zone etc., are all taken into account. The deformation of work rolls is calculated with the influence function method and an arbitrary contact are shape is permitted. The strip deformation is modeled by the slab method and the entry and exit elastic deformation zones are included. The preliminary displacement principle is used to determine the boundaries and to calculate the friction of the central preliminary displacement zone. The model is calibrated against the production mill data and installed in the setup computer of a temper rolling mill in POSCO. The validity and precision of the model have been proven through a comparison of the measured roll forces and the predicted ones.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 춘계학술대회 논문집
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• pp.616-621
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• 2003

MIG or TIG welding has been the most popular welding process for joining aluminum alloy structures. However, porosity, hot crack and distortion were serious problems in inert gas fusion welding. Since FSW(Friction Stir Welding) was invented by TWI in 1991, it has been the powerful candidate for solving the problems of inert gas welding. In this paper, the principle and characteristics of FSW is introduced and its application to rolling stocks is presented to make basis for future development in production technology of aluminum rolling Stocks.

• 대한기계학회논문집
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• 제13권5호
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• pp.831-836
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• 1989

본 연구에서는 이에 대한 검토를 하기 위하여, Kato의 속도장을 수정하여 수치게산한 폭 증가율과 알루미늄을 재료로 실험한 결과를 비교하고, 마찰비와 판폭비 및 압하율의 변화에 따른 폭 증가율의 영향에 대하여 고찰하였다.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1996년도 제24회 춘계학술대회
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• pp.126-132
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• 1996

A laboratory scale hot strip rolling wear simulator(HRWS) was developed for the purpose of investigating the tribological phenomena occurred in production hot strip rolling mills. The HRWS' main parts are the electric heater, the mechanical descaler, tandem type 2-4Hi rolling mill stands, the cooling chamber, the tension controller and coiler. By simulating the tribelogical phenomena in rolling process at laboratory, wear patterns, cracks, cat-ear wear, black film, effect of hot rolling oil lubrication, etc. were reproduced, and discussed on the performace of simulator.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 추계학술대회 논문집
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• pp.453-455
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• 2005

Ferritic STS 439 Steel sheet were deformed by hot rolling with and without lubricant. The effect of friction between roll and specimen on inhomogeneous texture was studied by means of EBSD, XRD texture analysis. The textures were compared with those of obtained by Taylor FEM simulation. High friction between roll and sheet gave rise to the formation of the inhomogeneous shear texture through thickness.

• 한국정밀공학회지
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• 제28권1호
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• pp.40-47
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• 2011

Mobile harbor which is a novel concept of ocean transportation to bring the containers from the cargo ship waiting on the ocean away is being focused now. To provide the mobile harbor with the stable loading/unloading condition, it is necessary to develop the oscillation mitigation technologies such as anti-rolling system. Anti-rolling system using AMD(Active Mass Driving) has merits that it can handle the disturbances more actively and mitigate the rolling oscillation faster than other type anti-rolling system. However, rack-and-pinion type AMD has problems such as big friction noise from gears and motor, wear and tear, and continuous maintenance. In this paper, novel anti-rolling system using Maglev type AMD for mobile harbor is suggested in order to resolve the problems caused by the friction. This novel anti-rolling system doesn't make any friction because it supports the moving mass by using magnetic levitation force and moves it by using propulsion force from the linear motor. The demo system of the novel anti-rolling system using maglev type AMD has been developed in order to investigate its feasibility. This paper presents the procedures and results of development of this demo system.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1997년도 춘계학술대회논문집
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• pp.85-88
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• 1997

The effect of lubrication on the evolution of the cold rolling texture in low carbon steels was studied by X-ray texture measurement. The cold rolling texture was inhomogeneous through the thickness of the rolling sheet. The type and sharpness of the texture through the thickness and the degree of inhomogeneity were found to be dependent on the friction acting between rolls and the rolled materials. The degree of the through thickness inhomogeneities was higher in the specimen rolled without lubrication. The friction acting on the roll surface led to the formation of the Goss-Orientation in the rolling texture.

• Tribology and Lubricants
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• 제29권4호
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• pp.218-222
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• 2013

Water-lubricated ball bearings consist of rolling elements, an inner raceway, an outer raceway, a retainer, and an operating lubricant. In the water environment, ball bearings are required to sustain high loads at high speeds under poorly lubricated conditions. For the analysis of bearing behavior, friction torque is considered as the main factor at various flow rates, rotating speeds, and roughnesses between the rolling element and raceways. When the bearing operates at high rotating speeds, the friction torque between the raceway and rolling elements increases considerably. This frictional torque is an important factor affecting bearing reliability and life cycle duration. For understanding the flow conditions in the inner part of the bearing, this study focuses on the flow around the rotating and revolving rolling elements. A simple model of fluid flow inside the ball bearing is designed using the commercial CFD program ANSYS.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2003년도 춘계학술대회논문집
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• pp.136-138
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• 2003

Strain states of clad sheets consisted of AL3003 and SUS430 were studied by FEM simulation. Main simulation parameters include roll size, reduction, material properties, material temperature, and friction between roll and material (or friction between materials). To investigate the effect of friction on the evolution of strain states, the friction coefficient between roll and material (or fraction coefficients between materials) was varied. Components of strain rate, strain were compared according to the variation of friction coefficients. And strain states during cladding were compared with those induced by simple rolling process.

• 대한기계학회논문집A
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• 제40권2호
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• pp.199-206
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• 2016

LM 볼가이드는 구름접촉을 갖는 이송시스템의 핵심요소로서 공작기계, 반도체 장비, 로봇 등 정밀기계에 널리 사용된다. 그러나 LM 볼가이드에서 발생하는 마찰력은 마찰열을 유발하여 위치 정도를 저하시키고 강성과 예압 변화를 야기한다. 이런 영향을 정확하게 분석하여 정밀 기계설계에 응용하기 위해서는 마찰력 모델의 정식화가 요구된다. 본 논문에서는 구름마찰, 점성마찰, 슬립마찰을 고려한 LM 볼가이드의 정확한 마찰력 모델을 유도한다. 그리고 다양한 조립, 부하 및 속도 조건에서 실험을 수행하여 마찰력 모델의 신뢰성을 검증하고, 마찰력 모델로부터 마찰 성분의 영향력을 분석한다.