• 제목/요약/키워드: Groove Rolling

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공형압연에서 소재 주름흠 발생 해석 - 유한요소해석 (Analysis of wrinkle Initiation on Workpiece in Groove Rolling - Finite Element Analysis)

  • 나두현;조오영;이종호;이용희;이영석
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2008년도 춘계학술대회 논문집
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    • pp.415-418
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    • 2008
  • We propose a criterion which predicts wrinkle initiation on workpiece in groove rolling process based on finite element analysis. Fundamental idea introduced in the criterion is to examine the difference between flat rolling which don't' cause wrinkling at all and groove rolling which usually accompanies it. The proposed criterion assumes that irregular distribution of shear strain on workpiece during groove rolling is attributable to the initiation of wrinkling. The proposed criterion has been applied to roughing train in the rod and bar mill of SEAH BESTEEL Inc. A new design for 2nd pass (square roll groove) was suggested, machined and applied. Results reveal that the proposed criterion in this study could point out the location of wrinkle initiation during groove rolling and could reduce onset of wrinkle on final products.

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공형압연에서 소재 주름흠 발생 감소를 위한 유한요소해석 (Finite Element Analysis to Reduce the Wrinkle Initiation of Workpiece in Groove Rolling)

  • 나두현;조오영;이종호;이용희;이영석
    • 소성∙가공
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    • 제17권5호
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    • pp.328-336
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    • 2008
  • A criterion which predicts wrinkle initiation on workpiece in groove rolling process based on finite element analysis is proposed. Fundamental idea considered in the criterion is using the difference between flat rolling which don't cause wrinkling at all and groove rolling which usually accompanies it. The proposed criterion assumes that irregular distribution of shear strain on workpiece during groove rolling is attributable to the initiation of wrinkling. The proposed criterion has been applied to roughing train in the rod mill of SEAH BESTEEL Inc. A new design of 2nd pass (square roll groove) was suggested, machined and applied. Results reveal that the proposed criterion could point out the location of wrinkle initiation and could reduce onset of wrinkle.

순수 알루미늄의 판재압연 및 공형압연시 가공경로에 따른 변형분포와 기계적 성질의 예측 (Study of the Effect of Loading Path on the Strain and Mechanical Properties of Aluminum with Flat and Groove Rolling Experiment)

  • 김성일;변상민
    • 소성∙가공
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    • 제17권6호
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    • pp.420-428
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    • 2008
  • The effect of loading path changes on the strain and mechanical properties of a commercial pure aluminum was studied using flat rolling and groove rolling. Material during flat rolling undergoes a continuous monotonic compressive loading, while one during groove rolling experiences a series of cross compressive loading. Four-pass flat rolling and groove rolling experiment are designed such that the aluminum undergoes the same amount of the strain at each pass. The rolling experiment was performed at room temperatures. Specimens for tensile test are fabricated from the plate and bar rolled. In addition, the strain distribution for the plate and bar cold rolled specimens is also calculated by finite element method. The results reveal that differences of loading path attributed by monotonic loading(flat rolling) and cross loading(groove rolling) significantly influence the mechanical properties such as yield stress, ultimate tensile stress, strain hardening and elongation. It is clear that the different loading path can give raise to change the deformation history, although it is deformed with same amount of strain for same material.

유한요소해석을 이용한 공형 압연에서의 표면흠 발생 연구 (A Study of Surface Defect Initiation in Groove Rolling Using Finite Element Analysis)

  • 나두현;허종욱;이영석
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2008년도 추계학술대회 논문집
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    • pp.333-336
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    • 2008
  • The groove rolling is a process that transforms the bloom or billet into a shape with circular section through a series of rolling. Inhibition of surface defect generation in groove rolling is a matter of great importance and therefore many research groups proposed a lot of models to find the location of surface defect initiation. In this study, we propose a model for maximum shear stress ratio over equivalent strain to catch the location of surface defect onset. This model is coupled with element removing method and applied to box groove rolling of POSCO No. 3 Rod Mill. Results show that proposed model in this study can find the location of surface defect initiation during groove rolling when finite element analysis results is compared with experiments. The proposed criterion has been applied successfully to design roll grooves which inhibits the generation of surface defect.

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공형 압연에서의 표면흠 성장 모델링 및 제어 방법 연구 (Modeling and Controlling of Surface Defect Initiation and Growth in Groove Rolling)

  • 나두현;이영석
    • 소성∙가공
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    • 제17권8호
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    • pp.607-612
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    • 2008
  • The groove rolling is a process that transforms the bloom or billet into a shape with circular section through a series of rolling. Inhibition of surface defect generation in groove rolling is a matter of great importance and therefore many research groups proposed a lot of models to find the location of surface defect initiation. In this study, we propose a model for maximum shear stress ratio over equivalent strain to catch the location of surface defect onset. This model is coupled with element removing method and applied to box groove rolling of POSCO No.3 Rod Mill. Results show that proposed model in this study can find the location of surface defect initiation during groove rolling when finite element analysis results is compared with experiments. The proposed criterion has been applied successfully to design roll grooves which inhibit the generation of surface defect.

그루브 압축에 의한 알루미늄의 집합조직 (Texture Development by Groove Pressing in Aluminum)

  • 박종진
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2000년도 춘계학술대회논문집
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    • pp.206-209
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    • 2000
  • Groove pressing which is analogous to groove rolling in the aspect of deformation mode was designed and influence of the uncommon shear deformation on the development of texture and R value was investigated. Texture developed by the groove pressing were measured as well as predicted. It was found out that the main component in the developed texture was {40。, 45。, 0。} in ODF which was regarded as a rotated Bs component and rarely observed in a plain rolling. The maximum R value was predicted to be 3.8 in 45。 direction which might be attributed to the new component.

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볼 베어링의 구름 요소 주위 유동 특성에 대한 해석 (Analysis of Fluid Flow Characteristics Around Rolling Element in Ball Bearings)

  • 조준현;김충현
    • Tribology and Lubricants
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    • 제28권6호
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    • pp.278-282
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    • 2012
  • Various bearings such as deep-groove ball bearings, angular-contact ball bearings, and roller bearings are used to support the load and to lubricate between the shaft and the housing. The bearings of potential rolling systems in a turbo pump are the deep-groove ball bearings as comparing with the bearings with rolling elements such as cylindrical rollers, tapered cylindrical rollers, and needle rollers. The deep-groove ball bearings consist of rolling elements, an inner raceway, an outer raceway and a retainer that maintain separation and help to lubricate the rolling element that is rotating in the raceways. In the case of water-lubricated ball bearings, however, fluid friction between the ball and raceways is affected by the entry direction of flow, rotation speed, and flow rate. In addition, this friction is the key factor affecting the bearing life cycles and reliability. In this paper, the characteristics of flow conditions corresponding to a deep-groove ball bearing are investigated numerically, with particular focus on the friction distribution on the rolling element, in order to extend the analysis to the area that experiences solid friction. A simple analysis model of fluid flow inside the water-lubricated ball bearing is analyzed with CFD, and the flow characteristics at high rotation speeds are presented.

정상 상태 롤링 해석 기법 적용을 통한 타이어 패턴 형상에 따른 PRAT 특성 연구 (The Study on PRAT Performance due to Tire Pattern Shapes using Steady State Rolling Analysis Method)

  • 성기득;박현만;구병국;조춘택
    • 한국자동차공학회논문집
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    • 제16권5호
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    • pp.15-21
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    • 2008
  • It is generally known that the PRAT(Plysteer Residual Aligning Torque) is one of indicating a performance factors of a tire for assessing the vehicle pull, also tire pattern shape, which means lateral groove angle, is very important tire design factor in relation to the PRAT. Lateral grooves of tire pattern are widely divided into center and shoulder parts. So, this paper has studied the correlation between the PRAT and their lateral groove angles using FEM. Especially, the steady state rolling analysis among tire rolling analysis methods has been used for the PRAT performance study. Firstly, analysis result data have been compared with the experimental data to validate FE analysis for PRAT. Next, the PRAT due to the lateral groove angle about PCR(Passenger Car Radial) tire and SUV tire has been analyzed. The tendency of the PRAT due to the lateral groove angles can be used as a guide line for the tire design in relation to vehicle pull.

L형상 프로파일 링롤링 공정의 하부면 그루브 결함 분석 (Analysis of the Bottom Groove in L-shaped Profile Ring Rolling)

  • 오일영;황태우;강필규;문영훈
    • 소성∙가공
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    • 제27권5호
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    • pp.289-295
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    • 2018
  • The profile ring rolling process can realize various ring shapes unlike conventional rectangular cross-sectional ring products. In this paper, the defective groove in the bottom surface of L-shaped ring products was analyzed. Grooves are generated by non-uniform external forces due to profile main roll and initial blank shape. Process parameters such as the motion of dies and working temperature were determined. Mechanism of groove formation was analyzed by FE simulation on the basis of local external forces acting on the blank. Analysis results were similar to the groove actually occurring in the production line. Based on results of the analysis, two solutions were proposed for the groove. The position of the base plate supporting the blank was adjusted and edge length of the main roll was extended to suppress growth of grooves. It has been verified that groove was improved by applying two proposed methods in the shop-floor.

그루브 압축이 알루미늄 집합조직에 미치는 영향 (Effect of Groove Pressing on Deformation Texture in Aluminum)

  • 김영석;박종진
    • 소성∙가공
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    • 제9권4호
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    • pp.421-427
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    • 2000
  • The present study has focused on the development of shear textures during groove pressing in an aluminum alloy sheet. The shear components 23 and 13 developed during the groove pressing process. The process consisting of two steps of grooving and flattening each effectively gave rise to a high shear deformation In the sheet without reduction in thickness. The main texture component obtained from the process was the rotated Bs-orientation. The evolution of shear components during the groove pressing caused an increase in R-value of aluminum sheet comparing to a normally processed rolled sheet.

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