• 제목/요약/키워드: Metal-rolling

검색결과 200건 처리시간 0.028초

홀 펀칭공정에서 이방성 발전에 관한 연구 (Development of anisotropy in the hole punching process)

  • 윤종헌;이용신;김승수;김응주;허훈
    • 한국소성가공학회:학술대회논문집
    • /
    • 한국소성가공학회 2005년도 추계학술대회 논문집
    • /
    • pp.287-290
    • /
    • 2005
  • The shearing and punching processes are analyzed with the finite element method using an isotropic material model. The experimental result in the punching process shows that final radiuses of sheet metal according to the rolling direction and transverse direction are different because of the material anisotropy. The material anisotropy is induced by complicated large deformation in the polycrystalline aggregate. The contact region between the punch and sheet metal experiences severe deformation such as shear, compression and tension in the punching process. In this paper, the analysis of punching process for Al 1100 is performed with the ABAQUS Standard. The analysis of texture development and evolution is carried out based on the deformation history in the punching process. The deformation histories are extracted by UMAT in the ABAQUS Standard. The torture development is investigated with the pole figure and yield surface during the punching process.

  • PDF

알루미늄 마이크로 박판소재의 방향성에 관한 실험적 연구 (An experimental study on the oriented mechanical properties of aluminum micro thin foil material)

  • 이혜진;이낙규;최석우;이형욱;최태훈;황재헉;곽동기
    • 한국소성가공학회:학술대회논문집
    • /
    • 한국소성가공학회 2005년도 추계학술대회 논문집
    • /
    • pp.295-298
    • /
    • 2005
  • This paper is concerned with the precision material property measurement of a micro metal thin foil that is used in MEMS technology. Since these MEMS components require great precision and accuracy, evaluation of reliability such as the lift cycle endurance test, impact test, and residual stress test is necessary for these components. However, in practice, real reliability tests are not easy to perform due to consideration of various factors. Rather than actual testing, it would be much easier to evaluate the reliability of components by the analytical approach. Although the analytical method is utilized by software tools, it is obviously necessary to acquire fundamental properties of materials through real test methods. In this paper, the oriented mechanical properties of aluminum thin foil are measured by nano scale material property measurement system.

  • PDF

고속열차 점착계수 향상을 위한 신규 복합재료 분말 마찰조절재 개발 및 점착력 특성 평가 (Development of Novel Composite Powder Friction Modifier for Improving Wheel-rail Adhesion in High-speed Train)

  • 오민철;안병민
    • 한국분말재료학회지
    • /
    • 제25권6호
    • /
    • pp.501-506
    • /
    • 2018
  • With the recent remarkable improvements in the average speeds of contemporary trains, a necessity has arisen for the development of new friction modifiers to improve adhesion characteristics at the wheel-rail interface. The friction modifier must be designed to reduce slippage or sliding of the trains' wheels on the rails under conditions of rapid acceleration or braking without excessive rolling contact wear. In this study, a novel composite material consisting of metal, ceramic, and polymer is proposed as a friction modifier to improve adhesion between wheels and rails. A blend of Al-6Cu-0.5Mg metallic powder, $Al_2O_3$ ceramic powder, and Bakelite-based polymer in various weight-fractions is hot-pressed at $150^{\circ}C$ to form a bulk composite material. Variation in the adhesion coefficient is evaluated using a high-speed wheel-rail friction tester, with and without application of the composite friction modifier, under both dry and wet conditions. The effect of varying the weighting fractions of metal and ceramic friction powders is detailed in the paper.

TMCP 강의 용접열영향부 인성에 관한 연구

  • 신민태;윤중근;김희진
    • Journal of Welding and Joining
    • /
    • 제4권3호
    • /
    • pp.43-49
    • /
    • 1986
  • Weldability of the TMCP steel manufactured by controlled rolling followed by accelerated cooling process was investigated. For comparison, two other steel plates produced by different manufacturing processes were selected; normalized and controlled rolled. Tandem submerged arc welding with both side one run technique was carried out. The results of this study can be summarized as follows; TMCP steel having the lowest carbon equivalent shows the best combination of mechanical properties, not only in the base metal but also in the heat affected zone. In the HAZ, the accelerated colling effect imarted on the trengthis releved by the weld thermal cycles, and thus the strength of the welded joint decrease substantially accompanied with the fracture in the HAZ. On the other hand, not only the softening but the fine microstructure can preserve the high toughness of TMCP steel in the HAZ.

  • PDF

롤 성형기를 이용한 금속 내부구조물 기초 실험 (A study on basis of metal inner structure by roll forming machine)

  • 김형종;정동원;최두선;제태진;박재현
    • 한국정밀공학회:학술대회논문집
    • /
    • 한국정밀공학회 2004년도 추계학술대회 논문집
    • /
    • pp.1452-1455
    • /
    • 2004
  • Sandwich structures, which are composed of a thick core between two thin faces, are commonly used in many engineering applications because they combine high stiffness and strength with low weight. Depending on the application of a particular sandwich structure, various types of cores can be used. The production of sandwich sheets by a rolling process, which is a more efficient and economical approach compared to other types of processes, has become an increasingly important subject of study. In this paper, we have studied the embossing structure of sheet type and developed embossing roll mold with $\Phi$3 pattern and roll forming system.

  • PDF

열전달과 열탄소성변형의 연결해석 (Coupled Analysis of Heat Transfer and Thermoelastoplastic deformation)

  • 이용기;한흥남;오규환;이동녕
    • 한국소성가공학회:학술대회논문집
    • /
    • 한국소성가공학회 1994년도 춘계학술대회 논문집
    • /
    • pp.47-54
    • /
    • 1994
  • The study is concerned with the coupled analysis of heat transfer and thermoelastoplastic deformation. The thermoelastoplastic model is very useful for the analysis of residual stress and the analysis of thermal stress as well as the analysis of metal forming. Heat of deformation, phase transformation and contact heat transfer boundary are considered. The contact heat transfer boundary is treated by the interpolation of shape function. The analysis of deformation and the analysis of heat transfer are carried out for the could upsetting and the hot rolling. The computed results are found to be in good agreement with the experimental results.

  • PDF

알루미늄 튜브 온간 하이드로포밍 성형성에 관한 연구 (Studies on the Warm Hydroformability of Aluminum Tubes)

  • 김봉준;류종수;김대현;김동우;문영훈
    • 한국소성가공학회:학술대회논문집
    • /
    • 한국소성가공학회 2004년도 춘계학술대회 논문집
    • /
    • pp.198-201
    • /
    • 2004
  • Aluminum alloys have high potential for weight reduction in automotive and other applications. But aluminum alloys have relatively low tubular hydroformability which can be enhanced by conducting the hydroforming at elevated temperatures. Hot working processes are commonly used in bulk forming such as forging and rolling, but still is rare in sheet metal forming like hydroforming. In this study hydroforming test at elevated temperatures is performed by special designed induction heating system to investigate the hydroformability of aluminum alloys. The high temperature formability characteristrics are obtained by 1?fitting forming test and circular bulging test and the effects of the process parameters such as feeding amount, internal pressure and temperatures on the tubular forming limits are mainly investigated.

  • PDF

냉간 등방압 성형공정을 이용한 마이크로 엠보싱 패턴 성형 및 기계적 물성 측정 (Fabrication Method Of Micro Embossing Patterned Metallic Thin Foil Using CIP Process and It's Mechanical Property)

  • 이혜진;이낙규;이근안;이형욱;최석우
    • 한국소성가공학회:학술대회논문집
    • /
    • 한국소성가공학회 2006년도 춘계학술대회 논문집
    • /
    • pp.243-246
    • /
    • 2006
  • In this paper, Experimental results on the measurement of mechanical properties of fine patterns in the MEMS structure are described. The mechanical properties of embossing patterns on metallic thin foil is measured using the nano indentation system, that is developed by Korea Institute of Industrial Technology(KITECH). These micro embossing patterns are fabricated using CIP(Cold Isostatic Press) process on micro metallic thin foils(Al-1100) that are made by rolling process. These embossing patterned metallic thin foils(Al-1100) are used in the reflecting plate of BLU(Back Light Unit) and electrical/mechanical MEMS components. If these mechanical properties of fine patterns are utilized in a design procedure, the optimal design can be achieved in aspects of reliability as well as economy.

  • PDF

비선형 유한요소법에서 선탐색 알고리즘의 적용에 의한 수렴속도의 개선 (Improvement of Convergence Rate by Line Search Algorithm in Nonlinear Finite Element Method)

  • 구상완;김낙수
    • 대한기계학회논문집A
    • /
    • 제27권8호
    • /
    • pp.1281-1286
    • /
    • 2003
  • A line search algorithm to increase a convergence in Newton's method is developed and applied to nonlinear finite element analysis. The algorithm is based on the slack line search theory which is an efficient algorithm to determine initial acceleration coefficient, variable backtracking algorithm proposed by some researchers, and convergence criterion based on residual norm. Also, it is capable of avoiding exceptional diverging conditions. Developed program is tested in metal forming simulation such as forging and ring rolling. Numerical result shows the validity of the algorithm for a highly nonlinear system .

입자요소를 이용한 미세 박판 부품의 유한요소 해석 기법 개발 (Development of FE Analysis Scheme for Milli-Part Forming Using Grain and Grain Boundary Element)

  • 구태완;김동진;강범수
    • 소성∙가공
    • /
    • 제11권5호
    • /
    • pp.439-446
    • /
    • 2002
  • This study presents a new computational model to analyze the grain deformation in a polycrystalline aggregate in a discrete manner and based directly in the underlying physical micro-mechanisms. When scaling down a metal forming process, the dimensions of the workpiece decrease but the microstructure of the workpiece remains the similar. Since the dimensions of the workpiece are very small, the microstructure especially the grain size will play an important role in micro forming, which is called size effects. As a result, specific characteristics have to be considered for the numerical analysis. The grains and grain boundary elements are introduced to model individual grains and grain boundary facets, respectively, to consider the size effects in the micro forming. The constitutive description of the grain elements accounts for the rigid-plastic and the grain boundary elements for visco-elastic relationships. The capability of the proposed approach is demonstrated through application of grain element and grain boundary element in the micro forming.