• Title/Summary/Keyword: Forging Load

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Experimental evaluation of splicing of longitudinal bars with forging welding in flexural reinforced concrete beams

  • Sharbatdar, Mohammad K.;Jafari, Omid Mohammadi;Karimi, Mohammad S.
    • Advances in concrete construction
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    • 제6권5호
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    • pp.509-525
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    • 2018
  • In this paper the application of forging process as benefit technique in Reinforced Concrete (RC) beam bars and comparison to lap splices was experimentally investigated with four concrete beam specimens with same dimensions and reinforcement details. The reference specimen was with no splices and the other three beams were with different splices (100% forging in the middle, 50% forging, and 100% lap splices in the middle). Beams were tested with the four points load system. Experimental test results indicated that using forging process as new bar splicing method can have high effects on increasing ductility and energy dissipation of concrete structures. It also proved that this method increased the flexural rigidity, energy absorption, and ductility of the RC beams. And also this research results showed that the flexural capacity and ductility of the beam with 50% forging were respectively increased up to 10% and 75% comparing to that of reference specimen, but the energy absorption of this beams was decreased up to 27%. The ductility of beam with 50% forging was increased up to 25% comparing the ductility of beam with 100% forging.

윤활제 및 표면 거칠기에 따른 베벨기어의 온간단조 성형성 평가 (Evaluation of Formability for Warm Forging of The Bevel Gear on The Lubricants and Surface Roughness)

  • 김동환;김병민
    • 한국정밀공학회지
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    • 제22권3호
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    • pp.21-28
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    • 2005
  • In the hot forging process lubricant influences on frictional condition only, but in the warm forging process it influence on the formability such as dimensional accuracy, filling state and frictional condition and it is important to estimate a lubricating characteristic of lubricants in the warm forging. In this paper, in order to evaluate the formability of billet in warm forging process according to the lubricant and lubricating method, lubricant and lubricating test have been performed using oil-based and water-based lubricant which were widely used in the hot and warm forging processes. The surface roughness of initial billet was measured to evaluate the influence on the formability of billet and the forming load and dimensional accuracy were compared and evaluated. From the experimental results, it can be known that water-based lubricants are more excellent than oil-based lubricants for warm forging of complex shape like a bevel gear. Also, in this study characteristics of deformation have been investigated according to surface treatment of initial billet.

초내열합금 터빈 디스크의 열간 단조 공정에 대한 공정 설계 및 미세조직 평가 (Process Design and Microstructure Evaluation During Hot Forging of Superalloy Turbine Disk)

  • 차도진;김동권;김영득;배원병;조종래
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2007년도 추계학술대회 논문집
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    • pp.190-194
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    • 2007
  • The forging process design and microstructure evolution for gas turbine disk of a Waspaloy is investigated in this study. Parameters related to deformation are die and preform geometry, and forging temperature of die and workpiece. Die and preform design are considered to reduce the forging load, and to avoid the forging defects. Blocker and finisher dies for multistage forging are designed and the initial billet geometry is determined. The control of hot forging parameters such as strain, strain rate and temperature also is important because the microstructure change in hot working affects the mechanical properties. The dynamic recrystallization evolution has been studied in the temperature range 900-$1200^{\circ}C$ and strain rate range 0.01-1.0s-1 using hot compression tests. Modeling equations are required represent the flow curve, recrystallized grain size, recrystallized volume fraction by various tests. In this study, we used to thermo-viscoplastic finite element modeling equation of DEFORM-2D to predict the microstructure change evolution during thermo-mechanical processing. The microstructure is updated during the entire thermal and deformation processes in forging.

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열간 자유단조시 내부 공극 압착 거동에 관한 유한요소해석 (FEM Analysis on Cavity Closure Behavior during Hot Open Die Forging Process)

  • 이영선;권용철;권용남;이승욱;김남수;이정환
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2007년도 추계학술대회 논문집
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    • pp.50-52
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    • 2007
  • Large size forged parts usually were made by hot open die forging because of the die cost, high applied load and small manufacturing quantities. Cast ingots were used in open die forging and the ingots almost included the cavities in its inside. Therefore, one of the aims for forging processes is to close and remove the cavities. However, its criteria were well not defined since the studies have many difficulties to investigate the cavity behaviors because of its large size. In this study, the cavity closure behavior was investigated by experimental and FE analysis. The FEM analysis is performed to investigate the overlap defect of cast ingots during free forging stage. The measured flow stress data were used to simulate the forging process of cast ingot using the practical material properties. Also the analysis of cavity closure is performed by using the $DEFORM^{TM}$-3D. The calculated results of cavity closure behavior are compared with the measured results before and after forging, which are scanned by the X-ray scanner. From this result, the criteria for deformation amounts effect on the cavity closure can be investigated by the comparison between practical experiment and numerical analysis.

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전자식 파킹 브레이크용 세레이션 기어의 냉간다단단조 공정 설계 및 후방 압출특성에 관한 평가 (Multi-stage Cold Forging Process Design and Backward Extrusion Characteristics Evaluation of Serration Gear for Electronic Parking Brake)

  • 서주한;최종원;정의은;강명창
    • 한국기계가공학회지
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    • 제21권2호
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    • pp.130-136
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    • 2022
  • Reducing production costs through net-shaped cold forging is an important aspect in the automobile industry. In this study, we intend to produce a net-shaped electronic parking brake (EPB) serration gear for automobiles, using multi-stage cold forging. These serrations are then assembled to the reduction gear of an EPB actuator. The forging process of the serrations and the cold forging design were verified through finite element analysis (FEA) in order to evaluate metal flow. The forging machine was selected by checking the load using FEA. Based on the FEA results, molds were designed, and parts were made using multi-stage cold forging to produce a net-shaped serration gear.

3차원 변형을 고려한 클로버 형상 소재의 업세팅 단조해석 (Analsis of Three-Dimensional Upst Forging of Clover-Shaped Disks)

  • 양동열;김종호
    • 대한기계학회논문집
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    • 제10권4호
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    • pp.535-540
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    • 1986
  • 본 연구에서는 소재의 3차원 변형, 즉 평면변형(sidewise spread)과 벌징변형 을 동시에 고려할 수 있는 간단한 동적가용 속도장을 제안하고 이를 클로버(clover) 시편의 업세팅 단조 해석에 적용해보기로 한다. 상계이론에 의한 전체 에너지 소비 율을 최소화시키면서 그때 그때의 높이 감소에 따른 단조 하중과 변형 형상을 구한다. 실험은 SM15C 탄소강을 이용하여 시편의 형상과 윤활조건을 바꿔가면서 상온에서 수행 한다.

터빈 블레이드의 형단조 금형설계 시스템 개발 (Development of Die Design System for Turbine Blade Forging)

  • 조종래
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 1999년도 춘계학술대회논문집
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    • pp.77-81
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    • 1999
  • The predictions of metal flow forging load optimal die angle and preform size are not so easy in turbine blade forging. First of all the quality of final product is influenced by side force which is one of the significant factors. in this study slab method is applied to determine optimal die angle minimizing side force and the position of preform Finally drawing of die design is obtained in optimal die angle with developing tool that is composed of Visual Basic.

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신경망을 이용한 열간단조품의 초기 소재 설계 (Design of Initial Billet using the Artificial Neural Network for a Hot Forged Product)

  • Kim, D.J.;Kim, B.M.;Park, J.C.
    • 한국정밀공학회지
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    • 제12권11호
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    • pp.118-124
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    • 1995
  • In the paper, we have proposed a new technique to determine the initial billet for the forged products using a function approximation in neural network. A three-layer neural network is used and a back propagation algorithm is employed to train the network. An optimal billet which satisfied the forming limitation, minimum of incomplete filling in the die cavity, load and energy as well as more uniform distribution of effective strain, is determined by applying the ability of function approximation of the neural network. The amount of incomplete filling in the die, load and forming energy as well as effective strain are measured by the rigid-plastic finite element method. This new technique is applied to find the optimal billet size for the axisymmetric rib-web product in hot forging. This would reduce the number of finite element simulation for determining the optimal billet of forging products, further it is usefully adopted to physical modeling for the forging design

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신경망을 이용한 열간단조품의 초기 소재 설계 (Design of Initial Billet using the Artificial Neural Network for a Hot Forged Product)

  • 김동진;김벙민;최재찬
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 1995년도 춘계학술대회 논문집
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    • pp.198-203
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    • 1995
  • In the paper, we have proposed a new technique to detemine the initial billet for the forged products using a function approximation in neural network. A three-layer neural network is used and a back propagation algorithm is employed totrain the network. An optimal billet which satisfied the forming limitation, minimum of incomplete filling in the die cavity, load and energyas well as more uniform distribution of effective strain, is determined by applying the ability of function approximation of te neural network. The amount of incomplete filling in the die, load and forming energyas well as effective strain are measured by the rigid-plastic finite element method. The new technique is applied tofind the optimal billet size for the axisymmetric rib-web product in hot forging. This would reduce the number of finite element simulation for determing the optimal billet of forging products, further it is usefully adapted to physical modeling for the forging design.

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Valve-Spring Retainer의 성형공정개선에 관한 연구 (A Study on the Improvement of Forming Processes of Valve-Spring Retainer)

  • 오현석;황병복;이호용
    • 소성∙가공
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    • 제5권2호
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    • pp.145-155
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    • 1996
  • The conventional five-stage forming processes of the valve-spring retainer are simulated using the rigid-plstiv finite element method. As a design criterion the improved process should satisfy the maximum forging load during processes within the loading limit of the available press and should not induce any geometrical defects. hollow bars are recommended as initial billets to skip the heading and piercing processes. Through various simulations it is found out that the one stage process results in less forging loads and better strain distributions.

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