• 제목/요약/키워드: Cast Element

검색결과 232건 처리시간 0.025초

알루미늄 함량에 따른 AGI (Austempered Gray Cast Iron)의 오스테나이트 형성 및 기계적 특성에 관한 연구 (Study on the Austenite Formation and Mechanical Properties of AGI (Austempered Gray Cast Iron) According to Aluminum Content)

  • 김동혁
    • 한국주조공학회지
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    • 제41권6호
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    • pp.543-549
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    • 2021
  • 알루미늄 주철은 내산화성, 내황화성 및 부식성이 우수하다. Ti, Ni 합금에 비해 비전략적 원소인 Fe를 사용하는 비용이 상대적으로 저렴하여 구조재 및 스테인리스강의 대체재로 기대되고 있다. 이는 스테인리스 스틸을 사용하는 경우에 비해 약 30%의 중량 감소 효과를 가져온다. 알루미늄 합금의 경우 최근 몇 년간 주철의 합금원소로 널리 사용되고 있는 원소이다. 실온에서 연성이 부족하고 600℃를 초과하면 강도가 급격히 감소하여 실용화가 지연되었다. 실온 연성이 약한 원인은 수소에 의한 환경 취화로 알려져 있으며, 이러한 특성의 약점을 개선하기 위해 다양한 합금원소의 첨가가 시도되고 있다. 회주철의 경도와 내마모성을 높이기 위해 주로 바나듐, 크롬, 망간 등의 합금원소를 사용하고 있지만, 이러한 원소를 포함하는 완제품의 가격과 합금화의 문제는 많은 한계가 있다.

연속 주조의 응고와 벌징에 관한 3차원 해석 (Three-dimensional Analysis for Solidification and Bulging of Continuously Cast)

  • 김영대;조종래;이부윤;하만영
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2000년도 추계학술대회 논문집
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    • pp.174-177
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    • 2000
  • In this paper, The bulging behavior of the solidified shell in continuously cast slabs have been numerically analyzed using three-dimensional elasto-plastic and creep finite element method Three-dimensional model has been applied in order to investigate the effect of the narrow face shell on restraining the bulging deflection. Solidification analysis are carried out by two-dimensional finite difference method. In this way, strains occurring at the solidification front near the narrow face of the slab, as well as those occurring in the board face have been computed. The adequacy of the model has been checked against the experimental results. In addition, the effect of the slab width and casting speed on the bulging are discussed.

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콘크리트 CIP 앵커시스템의 파괴 거동에 관한 연구 (Fracture behavior of Cast-in-place Headed Anchors to Concrete)

  • 박성균;김호섭;윤영수
    • 한국구조물진단유지관리공학회 논문집
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    • 제5권3호
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    • pp.141-152
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    • 2001
  • This paper presents the evaluation of behavior and the prediction of tensile capacity of anchors that can cause a failure of the concrete on the basis of the design for anchorage. Tests of cast-in-place headed anchors, domestically manufactured and installed in uncracked and unreinforced concrete member are conducted to test the effected of embedment length and edge distance. The failure modes and the load-deformation responses of the anchors are discussed and then the concrete failure data are compared with capacities by the two present methods : the 45 degree cone method of ACI 349, 318 and the concrete capacity design (COD) method. Differences between the results by test and by two prediction methods are analyzed Finite Element Method (FEM).

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Al-Cu첨가(添加)에 의(依)한 CV흑연주철(黑鉛鑄鐵)에 관한 기초연구 (A Study of the CV graphite cast iron with small additions of a Al-Cu alloy)

  • 전형탁;허보영;김수영
    • 한국주조공학회지
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    • 제3권4호
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    • pp.239-247
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    • 1983
  • CV graphite cast iron has been studied and generally known to have properties close to the average values of those between flake and spheroidal graphite cast iron. However, the thermal diffusivity of CV graphite cast iron is much larger than that of the average value of those between flake and spheroidal graphite cast iron. In this study, an easy production method of CV graphite cast iron with small additions of a Al-Cu which is known as the element of the graphitization was investigated. The effects of hold time and of Al-Cu additions after the treatments with spheroidizer (Fe-Si-Mg alloy) were also investigated. Increasing the additions of a Al-Cu alloy, the holding time to form a CV graphite cast iron was decreasing. Tensile strength and thermal diffusivity (flash method) were measured in order to find the changes of the mechanical properties and the physical properties. Spheroidal, CV, and flake graphite cast iron have tensile strengths 46.44, 38.29, and $27.29\;kg/mm^2$ and thermal diffusivities $3.95{\times}10^{-6,}$ $8.41{\times}10^{-6}$, $8.81{\times}10^{-6}m^2/sec$, respectively at room temperature.

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회주철 판형 주조품의 공정 셀 수와 칠 깊이에 미치는 두께, 기본 원소 및 접종제의 영향 (Effects of Thickness, Base Element and Inoculants on the Number of Eutectic Cells and Chill Depth of Gray Cast Iron Plate Casting)

  • 김태형;오정혁;권해욱
    • 한국주조공학회지
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    • 제31권3호
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    • pp.137-144
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    • 2011
  • The effects of thickness, base element and inoculants on the number of eutectic cells and chill depth of gray cast iron plate casting were investigated. Meanwhile the number of eutectic cells increased by inoculation, chill depth decreased. The former decreased and the latter increased by holding the melt at the temperature range between 1,450 and $1,500^{\circ}C$. The former was more for the thinner casting with the thickness of 5 mm than the other. The result of thermal analysis coincided well with the change of macrostructure. The former increased and the latter decreased with the increased contents of carbon, silicon and the silicon content by inoculation. The former decreased and the latter increased with increased manganese content. The performance of the Superseed Extra was the best among 5 inoculants.

박육주철의 공정 셀 수와 칠 깊이에 미치는 두께, 기본 원소 및 접종제 첨가 원소의 영향 (Effects of Thickness, Base Element and Additive to Inoculant on the Number of Eutectic Cells and Chill Depth of Thin-Section Gray Cast Iron)

  • 김태형;이우종;권해욱
    • 한국주조공학회지
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    • 제32권6호
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    • pp.261-268
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    • 2012
  • The effects of thickness, base element and additive to inoculant on the number of eutectic cells and chill depth of thin-section gray cast iron were investigated. Meanwhile the number of eutectic cells increased by inoculation, chill depth decreased. The former decreased and the latter increased by holding the melt at the temperature range between 1,450 and $1,500^{\circ}C$. The former was more for the thinner casting with the thickness of 5 mm than the other. The result of thermal analysis coincided well with the change of macrostructure. The former increased and the latter decreased with the increased contents of carbon, silicon and the silicon content by inoculation. The former decreased and the latter increased with increased manganese content. The number of eutectic cells decreased as the amounts of rare earth and the bismuth added to this inoculant increased. With the addition of sulfur of 0.10 wt% of the weight of this inoculant, the maximum number of eutectic cells was obtained.

C/V 흑연주철의 미세조직에 미치는 Cu 첨가의 영향 (Effects on Copper Addition on the Microstructure of Compacted Vermicular Graphite Cast Iron)

  • 박흥일;김명호
    • 한국주조공학회지
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    • 제6권4호
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    • pp.277-283
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    • 1986
  • The effects of copper as an alloying element on the microstructure of Compacted Vermicular graphite cast iron which was treated with Mg-REM spheroidizer have been studied. With the increase of copper content up to 2.0wt.%, the following results were obtained; First, the ratio of residual magnesium content in the as-cast iron has been found to be increased, possibly due to the decrease of sulfur content in the melt. Thus, the morphology of graphite in the as-cast iron has been found to be more nodular type. Second, the proportion of pearlite in the matrix has been found to he increased, however the matrix being with free carbide precipitates in the copper range of 1.2wt.% to 2.0wt.%. Third, the tensile strength of the as-cast iron in the temperature up to $400^{\circ}C$ was increased.

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Cast Stainless Steel (CF8M) 재료의 시험결과 분산을 고려한 유한요소 손상해석 (Finite Element Damage Analysis for Cast Stainless Steel (CF8M) Material Considering Variance in Experimental Data)

  • 전준영;김낙현;김윤재
    • 대한기계학회논문집A
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    • 제36권7호
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    • pp.769-776
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    • 2012
  • 본 논문의 유한요소 손상해석기법은 재료 인장물성과 파괴기준을 필요로 한다. 기존에 연구된 재료들은 노치인장 시험결과로부터 하나의 인장물성과 파괴기준을 구할 수 있었다. 그러나 본 논문에서 사용된 cast stainless steel(CF8M)의 경우, 동일한 조건의 노치인장 시험결과들에 분산이 존재하여 해석자에 따라 다른 인장물성과 파괴기준이 구해질 수 있다. 따라서 해석자에 관계없이 일관된 인장물성 및 파괴기준을 구할 수 있는 적절한 절차가 필요하다. 본 논문에서는 노치반경 16mm 의 인장시편 시험결과로부터 평균 인장물성을 구하였고, 이를 유한요소 해석에 적용하여 3 개의 파괴기준을 구하였다. 구해진 인장물성과 파괴기준을 적용하여 J-R 파괴인성 시험에 대한 손상해석을 수행하였고, 시험결과와 비교함을 통해 제시된 절차의 타당성을 검증하였다.

냉각곡선 분석을 통한 편상흑연주철의 공정반응에 미치는 희토류원소 및 냉각속도의 영향 평가 (Evaluation of Effects of Rare Earth Element and Cooling Rate on the Eutectic Reaction of Flake Graphite Cast Irons by Cooling Curve Analysis)

  • 이상환;박승연;이상목;김명호
    • 한국주조공학회지
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    • 제33권1호
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    • pp.13-21
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    • 2013
  • The effects of rare earth element (R.E.) and cooling rate on the eutectic reaction of flake graphite cast irons were studied by combined analysis of macro/micro-structure and cooling curve data. The correlation between eutectic reaction parameter and macro/micro-structure was systematically investigated. Two sets of chemical compositions with the different addition of R.E. were designed to cast. Three types of molds for cylindrical specimens with the different diameters were prepared to analyze cooling rate effect. The difference between undercooling temperature and cementite eutectic temperature (${\Delta}T_1=T_{U}-T_{E,C}$), which is increased by adding R.E. and decreased by increasing cooling rate, is considered to be a suitable eutectic reaction parameter for predicting graphite morphology. According to the criterion, A-type graphite is mainly suggested to form for ${\Delta}T_1$ over $20^{\circ}C$. Eutectic reaction time (${\Delta}t$), which is decreased by adding R.E. or increasing cooling rate, is a suitable eutectic reaction parameter for predicting eutectic cell size. Eutectic cell size is found to decrease in a proportion to the decrease of ${\Delta}t$.

쉘 적층 주조 구상흑연주철의 기계적 성질에 미치는 주형 변수 및 주 합금 원소의 영향 (Effects of Mold Variable and Main Alloying Element on the Mechanical Properties of Ductile Cast Iron Poured into Shell Stack Mold)

  • 김효민;권민영;천병철;권도영;김기엽;권해욱
    • 한국주조공학회지
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    • 제40권2호
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    • pp.25-33
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    • 2020
  • The effects of mold variable and main alloying element on the mechanical properties of ductile cast iron poured into shell stack mold were investigated. The strength and hardness of with the smaller cross-section of the diameter of 6.25mm were higher than those of 12.50mm. On the other hand, the elongation of the former was lower than that of the latter. The strength and hardness of the specimens obtained from the center layer in the 5-story stack mold were the lowest and those for other specimens were increased with increased distance from the center. The elongation of those were the highest of all. The strength and hardness of the specimens obtained from the center layer were decreased the elongation was increased with the increased number of layers. The strength and hardness were increased and the elongation was decreased roughly with the increased amounts of reaidual magnesium and carbon content added, respectively. The strength and hardness were increased and the elongation was decreased roughly with the increased amounts of silicon content added to 2.45wt% and rather decreased with that to 2.85wt%. The effect of silicon content showed the opposite tendency to those of residual magnesium and carbon content.