• 제목/요약/키워드: Preform

검색결과 465건 처리시간 0.047초

마그네슘 로드 휠의 유동성형 가공에 관한 연구 (A Study on Flow Forming Process of Magnesium Road Wheel)

  • 김정호;이종주;박수민;윤형석
    • 소성∙가공
    • /
    • 제23권2호
    • /
    • pp.116-121
    • /
    • 2014
  • Low pressure die casting and flow forming have been successfully used to produce sound road wheels from magnesium alloy AM80. In the current study, high speed compression testing was initially conducted to simulate the flow forming of a Mg wheel. Subsequently the flow forming was simulated with "Forge$^{TM}$", an FEM software package. On the basis of flow forming simulations, the flow forming of the Mg wheel was performed under different conditions. For the flow forming experiments, the preform castings were made by low pressure die casting from AM80, a commercial magnesium alloy. In flow forming of the magnesium preform wheel, the flow forming of the Mg wheel was successfully accomplished when the feed rate was less than half that for the forming of an aluminum road wheel. The reduction in feed rate was 52%. Finally, a comparison with the flow forming simulations was made.

유동성형에서의 연소관 예비성형체 두께별 소성변형 형태 (The Plastic Deformation of Combustion Chamber During the Flow Forming Process with Initial Preform Thickness)

  • 윤수진;이경훈;은일상
    • 한국추진공학회지
    • /
    • 제1권1호
    • /
    • pp.89-103
    • /
    • 1997
  • 현재 각종 미사일의 추진기관용 연소관을 제작하는데 이용되고 있는 유동성형공정에 대하여 강소성 구성방정식을 이용 유한요소해석을 수행하였다. 종전의 단일 롤러에 의한 해석과는 달리 3개의 롤러에 의한 연소관의 점진 소성변형을 고려하였으며, 이에 따른 각 롤러의 연소관에 대한 소성변형, 응력분포가 관찰, 분석되었다. 해석 결과 예비성형체의 두께에 따라 소성변형 형태와 그에 따르는 응력분포에 많은 차이가 나는 것으로 밝혀졌다. 또 이상적인 유동성형조건 하에서 반경 방향으로의 연소관의 유효 소성변형도는 거의 균일하게 나타났다.

  • PDF

Evaluation of Carbon Fiber distribution in Unidirectional CF/Al Composites by Two-Dimensional Spatial Distribution Method

  • Lee, Moonhee;Kim, Sungwon;Lee, Jongho;Hwang, SeungKuk;Lee, Sangpill;Sugio, Kenjiro;Sasaki, Gen
    • 한국산업융합학회 논문집
    • /
    • 제21권1호
    • /
    • pp.29-36
    • /
    • 2018
  • Low pressure casting process for unidirectional carbon fiber reinforced aluminum (UD-CF/Al) composites which is an infiltration route of molten Al into porous UD-CF preform has been a cost-effective way to obtain metal matrix composites (MMCs) but, easy to cause non-uniform fiber distribution as CF clustering. Such clustered CFs have been a problem to decrease the density and thermal conductivity (TC) of composites, due to the existence of pores in the clustered area. To obtain high thermal performance composites for heat-sink application, the relationship between fiber distribution and porosity has to be clearly investigated. In this study, the CF distribution was evaluated with quantification approach by using two-dimensional spatial distribution method as local number 2-dimension (LN2D) analysis. Note that the CFs distribution in composites sensitively changed by sizes of Cu bridging particles between the CFs added in the UD-CF preform fabrication stage, and influenced on only $LN2D_{var}$ values.

저압함침법에 의한 FeCrSi/AC8A 복합재료의 제조와 마모특성 평가 (Fabrication and Wear Property Evaluation for FeCrSi/AC8A Composite by Low-pressure Infiltration)

  • 송태훈;이현준;최용범;김성진;박원조
    • 한국해양공학회지
    • /
    • 제22권5호
    • /
    • pp.106-111
    • /
    • 2008
  • In this paper, study about property evaluation for the metal matrix composites fabricated by low pressure infiltration process. Aluminum alloy composite which is reinforced by Metal fiber preform was fabricated by low pressure casting process. Infiltration condition was changed the pressure infiltration time of 1 sec, 2 sec and 5 sec under a constant pressure of 0.4 MPa. The molten alloy completely infiltrated the FeCrSi metal perform regardless of the increase in the pressure acceleration time. The the porosity in the FeCrSi/AC8A composite was investigated. The porosity was reduced as the pressure acceleration time as shorter. The FeCrSi/AC8A composite was investigated the wear test for to know the relationship between Porosity and wear resistance. FeCrSi/AC8A composite at pressure acceleration time of 1sec is shown excellent wear resistance.

반응용탕단조법에 의한 (${Al_2}{O_3}$+Si)/Mg 하이브리드 금속복합재료의 제조 (Fabrication of Reaction Squeeze Cast (${Al_2}{O_3}$+Si)/Mg Hybrid Metal Matrix Composites)

  • 전상혁;오동현;박익민;조경목;최일동
    • 한국복합재료학회:학술대회논문집
    • /
    • 한국복합재료학회 2000년도 춘계학술발표대회 논문집
    • /
    • pp.109-115
    • /
    • 2000
  • In the present study, (10%$Al_2O_3$+5%Si)/AZ91 Mg hybrid composite was fabricated using the squeeze casting method. During squeeze casting, molten Mg was infiltrated into the preform of 10%$Al_2O_3$+5%Si and reaction product of $Mg_2Si$ intermetallic compound was formed by the reaction between molten Mg and Si powder. Microstructure has been observed and mechanical properties were evaluated for the reaction squeeze cast (RSC) hybrid composite. It was found that Si powder totally reacted with molten Mg to form $Mg_2Si$. Reinforcement ($Al_2O_3$) and the reaction product ($Mg_2Si$) are fairly uniformly distributed in Mg matrix for the squeeze cast hybrid composite. Mechanical properties were improved with hybridization of reinforcements, namely higher hardness and enhanced wear resistance comparing squeeze cast (15%$Al_2O_3$)/AZ91 Mg composite.

  • PDF