• 제목/요약/키워드: Billet Temperature

검색결과 115건 처리시간 0.023초

SKH51의 반응고 상태에서의 가열 및 성형에 의한 부품 제조 (Fabrication of a Part by Heating and Forming in the Semi-solid State of the SKH51 Material)

  • 이상용
    • 열처리공학회지
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    • 제27권3호
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    • pp.127-132
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    • 2014
  • The semi-solid metal forming process has been applied to realize a near-net shape fabrication of a high speed tool steel. A complicatedly shaped part out of SKH51 was successfully manufactured by introducing pertinent materials, tooling and processing conditions. A SKH51 billet with globular grains was heated at temperatures between 1300 and $1350^{\circ}C$ using high frequency induction heater to get semi-solid microstructure before high rate injection of mushy metal into a die cavity for the forming process. It was necessary to control the preheating of dies between 300 and $400^{\circ}C$ to maintain the homogeneous microstructure during the semi-solid metal forming process. Significant defects such as pores, high fraction of liquid fraction and segregation could be removed from the part by using air vents.

항공기용 알루미늄부품의 단조 공정설계연구 (Forging Process Design of Aluminium Alloys for Aircraft Parts)

  • 권영민;송정일;이영선;이정환
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2000년도 추계학술대회 논문집
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    • pp.90-93
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    • 2000
  • Al ally 7050 has been developed for higher strength and improved property against stress-corrosion cracking. Since the use of this alloy becomes more important for forged aircraft structural components. $\phi$ 65mm extruded billet has been forged for a highly-stressed aircraft parts. After forging processing and heat treatment, the forged parts showed undesirable microstructure caused by severe local grain coarsening at the surface layer and heavily-localized metal flow, the analysis of resulted in degraded mechanical properties. The above results have been compared to simulation by using the DEFORM-3D and those showed the thermomechamical processing must be optimized in terms of forging temperature, strain rate and deformation amount. To prevent the grain coarsening at the surface layer $\varepsilon$ heavily-localized grain flows.

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반용융 단조를 위한 복합재료의 수직형 고주파 유도가열 (Induction Heating of Vertical Type for Semi-Solid Forging with Metal Matrix Composites)

  • 이동건;허재찬;강충길
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2001년도 춘계학술대회 논문집
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    • pp.385-388
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    • 2001
  • In part forming process of metal matrix composites, the die casting and squeeze casting process are limited the size and dimension in term of final parts without machining. The thixoforming process for metal matrix composites has numerous advantages compared to die casting squeeze casting and compocasting. However, for the thixoforming process, the billet with the desired volume fraction must be heated to obtain a uniform temperature distribution over the entire cross-sectional areas. To obtain the reheating conditions of composites, the particulate reinforced metal matrix composites for thixoforming were fabricated by combined stirring process which is simultaneously performed with electro-magnetic stirring and mechanical stirring process.

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Cast alloy 718의 고온압축시 동적/정적재결정에 대한 연구 (Study about dynamic/static recrystallization during hot compression of Cast alloy 718)

  • 김남용;김정한;염종택;박노광;윤종원
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2006년도 춘계학술대회 논문집
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    • pp.207-210
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    • 2006
  • Behavior of dynamic/static recrystallization during hot deformation of Cast alloy 718 was investigated. For this purpose, hot compression test and FE-simulation were conducted via Thermecmaster-Z and DEFORM-3D, respectively. The microstructural evolution during hot compression and post heat-treatment was investigated and deformation mechanism were analyzed by stress-strain curve, FE-simulation and microstructure. FE-simulation results show that the temperature difference between top-die and billet has considerable influence on the final shape of compressed specimen. The relation between applied load and processing time was predicted by the FE-simulation.

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Thixoforming을 위한 금속 복합재료의 다단 재가열 공정 (Multi-Step Reheating Process of Metal Matrix Composites for Thixoforming)

  • 허재찬;강충길
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 1997년도 추계학술대회 논문집
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    • pp.180-183
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    • 1997
  • The forming process of metal matrix composites by the die casting and squeeze casting process are limited in size and dimension in term of final parts without machining. The thixoforming process for metal matrix composites has numerous advantages compared to die casting, squeeze casting and compocasting. The characteristics of thixoforming process can decrease the liquid segregation because of he improvement in fluidity in a globular microstructure state and utilizes flow without air entrapment. Therefore, in order to obtain the sound parts of metal matrix composites by using thixoforming process which as co-existing solidus-liquidus pahse, it si very important to obtain reheating condition. However, for he thixoforming process, the billet with the desired volume fraction must be heated to obtain a uniform temperature distribution over the entire cross-sectional areas. To obtain the reheating conditions of composites, the particulate reinforced metal matrix composites for thixoforming were fabricated by combined stirring process which is simultaneously performed with electro-magnetic stirring process which is simultaneously performed with electro-magnetic stirring and mechanical stirring process.

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헬리컬기어 블랭크 열간단조의 유한요소해석 (Finite-Element Analysis of a Helical-Gear Blank Hot-Forging)

  • 안승우;박종진
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 1995년도 제2회 단조심포지엄 단조기술의 진보
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    • pp.180-187
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    • 1995
  • Helical gears are machined from blanks, which are usually prepared by forging cylindrical billets at high temperatures through buster, blocker and finisher processes. As dimensions of the blank are closer to those of the machined part, machining cost can be more reduced. Therefore, there are a lot of efforts being made to optimize the forging processes in order to produce near-net shaped blanks. In the present investigation, a rigid viscoplastic finite element technique was used to analyze a helical gear blank hot forging processes and deformation, strain and temperature distributions, forging load variations during forging were obtained. In the paper, it is discussed how these results can be utilized to optimize die design, billet dimensions and press usage.

금속복합재료의 열간압출공정에 있어서 압출비가 섬유의 파단 및 배향에 미치는 영향 (Effect of the Extrusion Ratios on Fiber Breakage and Orientation in Hot Extrusion Process in Metal Matrix Composites)

  • 강충길;강성수;김봉향
    • 대한기계학회논문집
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    • 제17권7호
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    • pp.1740-1750
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    • 1993
  • The aluminar short fiber reinforced composite materials for hot extrusion were fabricated by semi-solid stirring method, and extruded at extrusion temperature $400^{\circ}C$ with various extrusion ratio. The hot extrusion load of volume fraction 15% metal matrix composites and base alloy Al7075 has been compared. The fiber length distribution, fiber breakage and fiber orientation are investiged to know the fiber behaviour in before and after hot extrusion. The tensile strength of the hot extruded billet are experimentally determined for different of extrusion ratios, and compared with theorically calculated strength.

소성변형 밀 마멸에 대한 열간 단조 금형의 수명 평가 (Life Estimation of Hot Forging Die by Plastic Deformation and Wear)

  • 이현철;김병민;김광호
    • 한국정밀공학회지
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    • 제20권2호
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    • pp.66-75
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    • 2003
  • This paper describes about the estimation method of die lift by wear and plastic deformation in hot forging process. The thermal load and the thermal softening are happened by the high temperature in hot forging process. Tool lift decreases considerably due to the softening of the surface layer of a tool caused by high thermal load and long contact time between tool and billet. Also, tool life is to a large extent limited by wear, heat crack and plastic deformation in hot forging process. Above all, the main factors which affects die accuracy and tool lift are wear and the plastic deformation of a die. The new developed technique for predicting tool life applied to estimate the production quantity for a spindle component and these techniques assist to improve the tool life in hot forging process.

소성변형 및 마멸을 고려한 열간 단조 금형의 수명 평가 (Tool life Evaluation of Hot Forging about Plastic Deformation and Wear)

  • 이현철;김동환;김병민
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2002년도 춘계학술대회 논문집
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    • pp.163-168
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    • 2002
  • Hot forging is widely used in the manufacturing of industry machine component. The mechanical, thermal load and thermal softening which are happened by the high temperature in hot forging process. Tool life decreases considerably due to the softening of the surface layer of a tool caused by a high thermal load and long contact time between the tool and billet. Also, tool life is to a large extent limited by wear, heat crack and plastic deformation in hot forging process. These are one of the main factors affecting die accuracy and tool life. That is because hot forging process has many factors influencing tool life, and there was not accurate in-process data. In this research, life prediction of hot forging tool by wear and plastic deformation analysis considering tempering parameter has been carried out for automobile component. The new developed technique in this study for predicting tool life can give more feasible means to improve the tool life in hot forging process.

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Al-Zn-Mg-Sc 합금의 고온압출에 미치는 공정조건의 영향 분석 (Effect of Processing Condition on the Hot Extrusion of Al-Zn-Mg-Sc Alloy)

  • 김남용;김진호;염종택;이동근;임수근;박노광;김정한
    • 소성∙가공
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    • 제15권2호
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    • pp.143-147
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    • 2006
  • Effect of processing condition on the hot extrusion of Al-Zn-Mg-Sc alloy was investigated. For this purpose, hot compression test and FE-simulation were conducted via Thermecmaster-Z and DEFORM-3D, respectively. The microstructure evolution during hot extrusion and post heat-treatment was investigated and deformation mechanisms were analyzed by constructing processing map. FE-simulation results show that the temperature difference between container and billet has considerable influence on the final shape of extruded T-shape bar. The relation between applied load and processing time was predicted by the FE-analysis as well as punch speed vs. stroke chart.