• 제목/요약/키워드: 강열점소성 유한요소법

검색결과 5건 처리시간 0.019초

유한요소법에 의한 열간성형공정에서 강의 미세조직변화 예측 (Prediction of Microstructural Evolution in Hot Forging of Steel by the Finite Element Method)

  • 장용순;고대철;김병민
    • 한국정밀공학회지
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    • 제15권7호
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    • pp.129-138
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    • 1998
  • The objective of this study is to demonstrate the ability of a computer simulation of microstructural evolution in hot forging of C-Mn steels. The development of microstructure is strongly dependent on process variables and metallurgical factors that affect time history of thermodynamical variables such as temperature, strain. and strain rate during deformation. Then finite element method is applied for the prediction of microstructural evolution, and it should be coupled with heat transfer analysis to consider the change of thermodynamical properties during forming process. In this study, Yada's recrystallization model and rigid-thermoviscoplastic finite element method are employed in order to analyze microstructural evolution during hot forging process. To show the validity and effectiveness of the proposed method, experiments are accomplished and the results of experiments are compared with those of simulations.

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2차원 절삭가공에 대한 강열점소성 유한요소법의 활용 (Application of the Rigid-Thermoviscoplastic Finite Element Method to Orthogonal Cutting Process)

  • 고대철;고성림;박태준
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 1997년도 추계학술대회 논문집
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    • pp.965-968
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    • 1997
  • The objective of this study is to develop a rigid-thermoviscoplastic finite element program for the analysis of orthogonal cutting process. Deformation of the workpiece material is considered as rigid-viscoplastic and the numerical solution is obtained from the coupled analysis bctween plastic deformation and temperature field, including treament of temperature dependent material properties. The chip and the burr formation are simulated for the non-steady state orthogonal cutting using the developed program. To validate the program the predicted results at chip and burr format~on stage are compared with the published ones. The case of isothermal cutting process is also considered to study the thermal effect on the machining process.

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강열점소성 유한요소법을 적용한 봉형상압연 공정설계에서의 공형 설계 및 롤속도 설정 (Roll Groover Design and Roll Speed Set-up in Bar Rolling Process Design using Rigid-thermo-viscoplastic FEM)

  • 권혁철;김수영;임용택
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 1999년도 제3회 압연심포지엄 논문집 압연기술의 미래개척 (Exploitation of Future Rolling Technologies)
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    • pp.88-97
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    • 1999
  • In this study, a systematic approach for roll pass design in bar rolling was studied. To minimize the trial and errors in the process design, a roll CAD system and a FE analysis system were combined. Based on the system, a methodology for roll pass design by FEM was studied. At first, designed process was compared with the FE analysis results and process redesign based on the FEM results was performed to obtain the specified final geometry. Then, empirical formula for roll speed set-up was compared with the FE analysis results. Further study on various simulations for bar rolling will help in making up for the inaccuracy in the currently used empirical roll speed rules. In addition, verification of the accuracy of the FE analysis system must be performed using experimental data in the industry.

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스프링부착 금형을 가진 다단 축대칭 단조공정의 유한요소해석-단조시뮬레이터 공정적용 사례(3) (Finite Element Analysis of a Multi-Stage Axisymmetric Forging Process Having A Spring-Attached Die)

  • 전만수;이석원;정재헌
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 1996년도 춘계학술대회논문집
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    • pp.93-100
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    • 1996
  • In this paper, a computer simulationtechnique for the forging process having a spring-attached die was presented . The penalty rigid-thermoviscoplastic finite element method was empolyed together with an interatively force-balancing method, in which the convergence was achieved when the forming load and the spring reaction force are in equilibrium within the user-specified allowable accuracy. The force balance was controled by adjusting the velocity of the spring-attched die. th minimize the number of internations, a velocity estimating schemewas proposed. Two application examples found in the related company were given. In the first application example, the predicted metal folw lines were compared with the acturally forged ones. in the second example, a hot forging process with a spring-attached die was simulated and the analyzed results were discussed in order to investigated the effects of spring-attached dies on the metal flow lines and the forming loads.

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베어링강의 고온변형 특성에 관한 연구 (A Study on Hot Deformation Behavior of Bearing Steels)

  • 문호근;이재성;유선준;전만수
    • 대한기계학회논문집A
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    • 제27권4호
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    • pp.614-622
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    • 2003
  • In this paper, the stress-strain curves of bearing steels at hot working conditions are obtained by hot compression test with a computer controlled servo-hydraulic Gleeble 3800 testing machine and elongations and reductions of area of the bearing steels are also obtained by hot tensile test with a Gleeble 1500 testing machine. Experiments are conducted under the various strain-rates and temperatures and their results are used to obtain the flow stress information. A rigid thermo-viscoplastic finite element method is applied to the multi-stage hot forging process in order to predict temperature distribution of workpiece. The experimental results and the analysis results are used to obtain an optimal hot forging condition.