Journal of the Korea Convergence Society (한국융합학회논문지)

Korea Convergence Society (한국융합학회)
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Factors Influencing Characteristics of Sand Core for Water Jacket in Automotive Cylinder Blocks Casting

자동차 실린더 블록 주조에서 워터 자켓용 샌드 코어 특성에 영향을 미치는 인자

  • Kim, Ki-Jun (Material Production Dep'2 / Ulsan Plant, Hyundai Motor Group)
  • Received : 2020.12.29
  • Accepted : 2021.02.20
  • Published : 2021.02.28
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Abstract

The characteristics of the foundry sand were analyzed for water jacket core required to prevent structural deformation from the heat generated in the cylinder bore during the casting of the cylinder block of an automobile. The sand core tensile strength tester, AFS-GFN, and optical microscope were used to evaluate the its properties. If the SiO2 content is high in the foundry sand, the dimensional defects and veining defects occur due to high temperature expansion. Also, if it is too low, the core breakage, porosities, chemical burn-on defects occur. The particle size index and grain shape influenced the core strength and resin consumption, resulting in fluctuations in defect types. The higher the alkalinity of the dried sand, the lower the core strength. And the more basic, the lower the core strength. At the resin content of 1.6~1.8%, the increase in core strength after 1 hour curing was approximately at its maximum.

본 자동차 실린더 블록 주조시 실린더 보어 내에서 발생하는 열로부터 구조적 변형을 방지하는데 필요한 워터 자켓 코어용 주물사의 특성을 분석하였다. 샌드 코어의 특성평가를 위하여 인장강도 시험기, 입도 지수(AFS-GFN), 광학현미경을 사용하였다. 주물사의 SiO2 함량이 높으면 고온팽창에 의한 치수 불량, 베이닝 불량이 발생하며, 너무 낮으면 코어 파손, 기포, 화학적 소착 등이 발생하였다. 입도 지수와 입형이 코어강도와 레진 소비량에 영향을 미치고, 이로 인한 불량 유형 변화가 발생하였다. 건조사가 염분이 높을수록 코어 강도는 감소하며, 알칼리성일수록 코어 강도가 감소하였다. 레진 함량 1.6~1.8%에서 1시간 경화 이후에 코어 강도 증가는 대략 최대를 보였다.

Keywords

References

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