• 제목/요약/키워드: Sand casting

검색결과 109건 처리시간 0.031초

타설 전과 후에 부식시킨 슬래브 시험체의 철근 부착특성에 관한 실험적 연구 (Experimental Study of Bond Characteristics on Slab Reinforcement Corroded Before and After Casting)

  • 김대일;조승호;정란
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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    • pp.1035-1040
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    • 2001
  • Recently, Sea-sand containing high levels of chloride is being applied to on reinforced concrete structures due to the exhaustion of river-sand and environmental problems, which affects directly corrosion of rebar in the RC structures. In this paper, characteristics of corroded rebar before and after casting were studied. Test results showed that bond strength of rebar corroded after casting was decreased with increase of corrosion level more rapidly than that of rebar corroded before casting.

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잔골재의 혼합비율 변화에 따른 수중불분리성 콘크리트의 특성에 관한 연구 (Study on the Properties of Antiwashout Underwater Concrete with Variation of Mixing Proportion of Fine Aggregate Types)

  • 배원만;박세윤;백동일;김명식
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2003년도 가을 학술발표회 논문집
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    • pp.533-536
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    • 2003
  • The objective of in this study makes investigation into the characteristics of antiwashout underwater concrete as to mix proportion, casting and curing water through experimental researches. in this study, sea sand is blended with river sand, crushed sand is blended with river sand and sea sand as to investigate the quality change and characteristics of antiwashout underwater concrete with variation of blend ratio of sea sand and crushed sand(0, 20, 40, 60, 80, 100%). Higher compressive strength is measured following the order of river sand, sea sand, crushed sand regardless of age and casting condition. Except for case of using river sand, blended ratio of 40% is appeared on most compressive strength.

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잔골재의 종류에 따른 수중불분리성 콘크리트의 특성에 관한 연구 (Study on the Properties of Antiwashout Underwater Concrete as to Fine aggreate Kinds)

  • 박세인;신현필;이환우;김종수;김명식
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2001년도 봄 학술발표회 논문집
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    • pp.941-946
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    • 2001
  • In this study, three kinds of fine aggregate (river sand, sea sand, crushed sand) were used and four different s/a (38%, 40%, 42%, 45%) were applied separately to this experimental for get the conclusion written below. Regardless of kinds of fine aggregate and casting-curing condition, maximum unit weight is seen at 40% of s/a and also to be seen in case of crushed sand. It's for that specific gravity of crushed sand is bigger comparatively than river sand and sea snad's one. Compressive strength is measured river sand, crushed sand, sea sand by order of size ; Regardless of variation of s/3, casting-curing condition and age. Compressive strength recorded maximum when s/a is 42% whatever sort of fine aggregate are. As the result, according to references, the optimum s/a of underwater antiwashout concrete is 40% but in this study, from compressive strength of view, the optimum s/a of underwater antiwashout concrete is 42%.

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잠수함 마스트 커버의 주조방안설계 및 주조해석 (Gating System Design and Casting Simulation for the Submarine Mast Cover)

  • 진철규
    • 한국산업융합학회 논문집
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    • 제26권5호
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    • pp.945-952
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    • 2023
  • In this study, the sand casting process was applied to design the gating system and perform casting simulation in order to domestically produce the submarine mast cover. Based on simulation results, casting experiments were conducted to produce a soundness prototype. The design concept of the mast cover's gating system was based on the design of bell casting. By arranging eight tower-type gates in a circle at 45° intervals, the flow of melt flowing into each gate was uniform and did not mix with each other, and the velocity of melt was also uniform. The mast cover made of Ni-Al-Bronze alloy has no unfilled parts. However, small porosities and flow marks occurred on the surface in several places. Yield strength and ultimate tensile strength are 279.3 MPa and 675.7 MPa, respectively, and elongation is 21.2%.

신속한 주물 시제품 개발을 위한 전산모사 기술과 산업용 단층촬영기 및 쾌속표형기의 적용 (The Application of Computer Simulation, Industrial CT and DLS RP for the rapid development of casting pilot models)

  • 유승목;임채호;조인성;최정길
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2006년도 춘계학술대회 논문집
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    • pp.195-196
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    • 2006
  • Direct laser sintering (DLS) technology for the resign coated sand is one of attractive technologies to produce molds and cores for the foundry industry rapidly and cost effectively. The objective of this case study is to develop casting pilot models using computer simulation technology, DLS RP machine and industrial computed tomography. The proposed casting design was verified by the Z-Cast software in the fields of fluid flow and solidification during the casting process. Casting parts with aluminum alloy using the post-curing treated sand moulds and cores are accurate to dimension and defect free.

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금형주조법에 의한 구상흑연주철의 제조 및 직접 템퍼링에 의한 충격인성 향상 (Casting of Ductile Cast Iron using Metal Mold and Improvement of Impact Toughness by Direct Tempering)

  • 최성배;이원식;홍영환
    • 열처리공학회지
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    • 제10권3호
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    • pp.159-164
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    • 1997
  • Non-alloyed and 1.0%Ni alloyed ductile cast iron were cast into the sand mold and metal mold, and finer graphite size was obtained in case of metal mold casting. Direct tempering after casting showed the slight increase of absorbed energy, which is largely due to the relieving of residual stress that is developed during casting. After austempering heat treatment, higher impact energy was obtained in case of metal mold casting than sand mold casting, which is due to the finer graphite size.

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주형에서 석탄분 첨가제(시콜)에 의한 주철주물의 소착억제기구에 관하여 (The Mechanism of Inhibiting Burn-on Sand to Iron Castings by Coal-dust (Seacoal) for a Molding Sand Additive.)

  • 홍영명;이영상;김동옥
    • 한국주조공학회지
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    • 제3권2호
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    • pp.100-105
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    • 1983
  • The mechanism of coal-dust action on inhibiting burn-on of Sand to iron castings was taken in consideration by means of casting test and thermal decomposition test. To compare the ability of inhibiting sand burn-on, test castings were produced in green sand moulds added three different coal-rusts. And quantitative determination of lustrous carbon and volatiles production for coal-dust samples were performed.The lustrous carbon production was in good agreement with the casting test result. But total voltiles production was relatively inefficient on hibiting sand burn-on to test castings.The lustrous carbon theory can be given to explain the mechanism which coal-dust inhibits sand burn-on to iron castings.

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토제 거푸집 무쇠솥 주조와 불미기술 연구 (A Study of Iron Pot Casting and Bellows Technology)

  • 윤용현;도정만;정영상
    • 헤리티지:역사와 과학
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    • 제53권2호
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    • pp.4-23
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    • 2020
  • 이 연구는 우리나라 철 주조기술의 다양성과 기술 체계를 규명하기 위한 목적으로 진행되었으며, 이를 위해 고문헌 조사 및 유물 분석, 제작 도구와 제작 기술에 대한 현지 조사 그리고 주조와 거푸집에 사용된 재료의 과학 분석 등을 실시하였다. 불미기술은 송풍구인 풀무를 이용하여 주철을 녹인 뒤 그 쇳물을 토제 거푸집에 부어 주물을 완성하는 철 주조기술로 현재 유일하게 제주도에서만 전승되고 있는데, 모래 거푸집을 사용하는 육지와 비교해 토제 거푸집을 사용하고 있다는 것이 큰 차이점이라 할 수 있다. 무쇠솥 주조기술에는 석비레, 모래, 점토 등을 섞어 만든 모래 거푸집을 이용한 주물사주조법(鑄物砂鑄造法)과 점토에 볏짚과 갈대 등을 섞어 만든 토제 거푸집을 이용한 도토주조법(陶土鑄造法)이 사용되고 있다. 주물사주조법에 의한 무쇠솥 주조는 거푸집 만들기, 속심 제작, 쇳물 작업, 거푸집에 쇳물 붓기, 완성품 다듬기 등 5단계의 작업공정을 거치며, 도토주조법에 의한 무쇠솥 주조는 거푸집 만들기, 거푸집 굽기, 질먹 입히기, 쇳물 작업, 쇳물 붓기, 완성품 다듬기 등 크게 6단계의 작업 공정으로 이루어진다. 두 주조법은 거푸집의 재료, 거푸집을 불에 굽고 질먹을 입히는 제작 공정에서 차이를 보인다. 이번에 연구한 불미기술은 토제 거푸집 무쇠솥 주조로 진흙 채취 및 반죽, 거푸집 제작, 초벌 굽기, 화적모살 및 질먹 바르기, 건조 및 비얄질, 거푸집 합장, 둑(용광로)제작, 재벌 굽기, 제련, 쇳물 붓기, 주물 다듬기 등 단계별 주조 공정에 사용된 재료 및 도구 분석과 제작 기술에 담겨진 과학 기술 원리를 규명하여 우리 고유 철 주조기술의 기술 체계를 밝혀 보았다. 그리고 무쇠솥 도토주조를 위해 이용한 재료와 완성품을 과학 분석한 결과, 거푸집은 주성분이 SiO2, Al2O3, Fe2O3으로 이루어진 진흙과 모래이고, 이형재는 SiO2, Al2O3, Fe2O3, K2O가 함유된 흑연이며, 완성된 무쇠솥의 미세 조직은 시멘타이트(Fe3C)와 펄라이트(페라이트와 시멘타이트의 층상 구조)로 이루어진 백주철 조직임을 확인하였다.

석고주조(石膏鑄造)한 Al-8.6% Si-3.6% Cu 합금(合金)의 기계적(機械的) 성질(性質)에 관(關)한 연구(硏究) (A Study on the Mechanical Properties of Al-8.6% Si-3.6% Cu Alloy Cast in Plaster Mold)

  • 여인동;김동옥;강인찬
    • 한국주조공학회지
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    • 제4권4호
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    • pp.5-13
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    • 1984
  • This paper is presented for showing the effect of cooling rate on dendrite arm spacing, correlated with the chilling power of molding materials (conventional plaster, foamed plaster, silica sand) and section thickness, and also showing relationship between dendrite arm spacing and mechanical properties for an aluminum - 8.6 percent silicon - 3.6 percent copper alloy. Local solidification time $(t_f)$ and secondary dendrite arm spacing (d) could be varied widely in accordance with the molding materials and casting thickness, and the following relationship is obtained: $d=9.4t_f\;^{0.31}$ A good correlation between dendrite arm spacing and mechanical properties such as ultimate tensile strength, yield strength, hardness was found, that is, mechanical properties decreased in a linear manner with increase in log of secondary dendrite arm spacing. Ultimate tensile strength in conventional plaster mold casting decreased by 15 percent comparing with the sand casting, where as in foamed plaster mold casting, it decreased by 30 percent comparing with the sand casting. From those results, it has been verified that DAS might be the most representative parameter for predicting mechanical properties varing with the different cooling condition.

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로타리압축기 실린더 Slot부의 주조조직에 따른 가공표면 및 마모특성에 관한 연구 (The Wear charactericstics and Machinability to The type of Cast-iron of The Slot part of cylinder for Rotary compressor)

  • 김동한
    • 한국윤활학회:학술대회논문집
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    • 한국윤활학회 1998년도 제27회 춘계학술대회
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    • pp.77-82
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    • 1998
  • The Part of slot on rotary compressor which plays an important part of the reliability and performance is studied on machinability and the wear characteristics for the specimen made by sand mold and permanent mold. The experiment are used the face cutter of milling machine which make the processing surface like broaching process and rollblock wear test machine. Permanent-mold casting iron is not affected by variation of RPM of milling machine, but sand-mold cast-iron is improved to increasing RPM. Also sand-mold casting iron shows superior wear characteristic to permanent-mold casting iron. This results from harder matrix of pearlite structure and self-lubrication characteristics of graphite. And wear particles in tested oil show shape and size similar to severe wear particles of oil taken from rotary compressor. The material and surface condition of slot play important part of the reliability and performance.

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