• 제목/요약/키워드: 2021 Al Alloy

검색결과 70건 처리시간 0.03초

정밀회전체의 언밸런스 변화에 따른 진동과 Al6061 알루미늄 합금 가공에 미치는 영향 (Effect of Unbalance on Vibration and Machining of Al6061 Aluminum Alloy in Precision Rotator)

  • 김민수;김정태;박석우;정동욱;최선호;구본흔;윤상환
    • 한국기계가공학회지
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    • 제20권3호
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    • pp.76-82
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    • 2021
  • At present, with the development of precision instruments, high dimensional accuracy of workpieces must be ensured. In particular, for the aluminum alloys used in automobiles, the surface roughness of the workpiece is extremely important. The dimensional accuracy and surface roughness of the workpiece is considerably affected by the rotational accuracy of the rotor. Therefore, to enhance the rotational accuracy, various variables such as those related to the components such as bearings, motors, and end mills, rotational speeds, and vibrations must be considered. In this study, the difference in the quality of the workpieces was compared considering the weight imbalance and rotational speed as variables.

알루미늄 주조용 SKD61 금형강의 표면처리 방법에 따른 특성 평가 (Characteristic Evaluation According to the Surface Treatment Method of SKD61 Mold Steel for Aluminum Casting)

  • 최세원;김철우;김용호;유효상
    • 열처리공학회지
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    • 제34권6호
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    • pp.281-286
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    • 2021
  • Arc ion plating (AIP), laser cladding, and nitriding are methods that can prevent mold damage or repair and create cracks and breakages on the die surface. The dissolution and soldering behavior of coated SKD61 by using arc ion plating, laser cladding, and nitriding was investigated. The structure of the coating was investigated as a function of deposition conditions by X-ray diffraction and the crystallographic orientation was determined using the texture factor. The TiAlN film deposited with AIP showed excellent corrosion resistance in the molten aluminum alloy at 680℃. In this paper, we have detailed the corrosion and mass loss phenomena associated with these steel-cast metal interactions.

AL6061과 PBT 재료의 인서트 사출공정조건에 따른 접합강도 특성 분석 (Analysis of Variations in the Bonding Strength Characteristics of the AL6061-PBT-Polymer Composite with Injection Parameters)

  • 정용준;김영신;전의식
    • 한국기계가공학회지
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    • 제20권5호
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    • pp.135-141
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    • 2021
  • As a trend of lightening automobiles and electronic products, several studies are currently underway to replace parts of metals with resins. In particular, heterojunctions between metals and resins are now under the spotlight. This study aims to evaluate the variation in bonding strength with process conditions when the polybutylene terephthalate (PBT) polymer is bonded to a specimen of the lightweight 6061 aluminum alloy (AL6061). Conditions of the bonding surface of the AL6061 specimen, the temperature of the injection mold, and the content of the glass fiber were considered to be process variables. Bonded specimens were manufactured for different values of these variables. Bonding strength tests were then performed on these specimens and variations were analyzed in their characteristics corresponding to those of the process conditions. Fractures in these specimens were assessed using scanning electron microscopy (SEM) to assess the fracture surface. This was then used to analyze the fracture shape and determine whether anodizing the specimen led to the development of cracks on the joint surface. Results of the above test indicated that while the surface condition of the specimen and the temperature of the injection mold significantly influenced the strength of bonding, the content of the glass fiber did not.

S20C 리벳된 Al5052와 SPFC980Y 강철 resistance-element 점용접 접합부의 미세조직 발달 및 고강도-부식 저항 특성 (Corrosion-Resistant High Strength S20C Element Riveted Al5052-SPFC980Y Steel Joints by Resistance Element Spot Welding)

  • 백승엽;송종호;박승연;송일종;이현철
    • 한국산학기술학회논문지
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    • 제22권2호
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    • pp.794-801
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    • 2021
  • 이 연구는 electric resistance element spot welding 프로세스를 도입하여 알루미늄 합금-강철의 이종 접합부의 기계적 강도 및 내식성을 향상시키기 위해 수행되었다. SPFC980Y 강철과 Al5052-H32가 각각 모재로써 적용되었고, S20C 강철은 리벳 element로써 음각과 양각의 형상으로 구분되며, Al5052-H32에 전기 저항 스폿 용접을 위해 리벳팅 되어 6.5 kA의 전류와 250 kgf/㎠의 가압력으로 접합되었다. 그 결과, 음각된 S20C element는 스폿 용접 공정 후 불안정한 너깃이 형성되는 반면, 양각된 S20C의 경우, 구조적으로 건전한 접합부로 건전한 내식성 및 탁월한 기계적 특성이 얻어졌다. FEM 시뮬레이션의 도입으로, 음각과 양각의 계면의 접합 특성이 수치적으로 밝혀졌으며, 시뮬레이션 결과는 미세조직 발달 양상을 수치적으로 뒷받침하였다. 이 연구는 element 스폿 용접된 H32-A5052 이종 접합부의 기계적 강도 및 부식 신뢰성에 대해 체계적으로 분석되었으며, 이 공정은 금속재료뿐만 아니라, 경량 비전도성 비철/비금속계 재료에도 적용 될 수 있기 때문에, 차세대 차체 경량화의 양산 기술로 확장 될 수 있다.

Al-xSi 합금의 인장특성에 미치는 공정 Si 입자의 파단과 미소기공율의 영향 (Effects of Damage Evolution of Eutectic Si Particle and Microporosity to Tensile Property of Al-xSi Alloys)

  • 이충도
    • 한국주조공학회지
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    • 제41권5호
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    • pp.434-444
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    • 2021
  • 본 연구에서는 미소기공과 Si석출상의 파단으로 구성되는 유효기공 면적분율에 대한 인장특성의 결함민감도 관점에서 Al-Si합금의 인장특성을 공정 Si입자의 분포양상 변화에 대하여 평가하고자 하였다. Al-xSi(x=2,5,8,11)합금의 주방상태 미세조직인 망상구조의 공정 Si입자는 T4처리를 통하여 과립형태로 변형시켰으며, CT분석과 주사전자현미경 관찰을 통하여 미소기공의 분포와 크기를 평가하였다. CT분석과 주사전자현미경의 비교분석을 통하여 인장변형과정에서의 균열성장이 최대 기공율을 포함하는 국부영역에서 발생함을 확인할 수 있었다. 그럼에도 불구하고 이들 분석방법에는 미소기공 인접영역에서의 소성변형집중과 미소기공의 분포양상에 의해 파생되는 실제적인 차이를 포함하기 때문에 정확히 일치된 결과를 얻을 수 없었다. 유효기공 면적분율의 변화에 대한 인장강도와 연신율의 변화는 과립형태보다 망상구조 정출상의 분율변화에 더욱 민감한 의존도를 가진다.

대기 및 Ar-0.2%SO2가스에서 Inconel 740 합금의 고온부식 연구 (Study of High Temperature of Inconel 740 Alloy in Air and Ar-0.2%SO2 Gas)

  • 이동복;김민정
    • 한국표면공학회지
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    • 제54권2호
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    • pp.43-52
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    • 2021
  • The Ni-based superalloy, Inconel 740, was corroded between 800 and 1100℃ for up to 100 hr in air and Ar-0.2%SO2 gas in order to study its corrosion behavior in air and sulfur/oxygen environment. It displayed relatively good corrosion resistance in both environment, because its corrosion was primarily dominated by not sulfidation but oxidation especially in Ar-0.2%SO2 gas. Such was attributed to the thermodynamic stability of oxides of alloying elements when compared to corresponding sulfides. The scales consisted primarily of Cr2O3, together with some NiAl2O4, MnCr2O4, NiCrMnO4, and rutile-TiO2. Sulfur from SO2 gas made scales prone to spallation, and thicker. It also widened the internal corrosion zone when compared to air. The corrosion resistance of IN740 was mainly indebted to the formation of protective Cr2O3-rich oxides, and suppression of the sulfide formation.

고온 압축 공정에서 금형과 알루미늄 빌렛의 접촉 열전달 계수 도출에 관한 연구 (A Study on Derivation of Contact Heat Transfer Coefficient Between Die and Aluminum Billet in High Temperature Compression Process)

  • 전효원;서창희;오상균;권태하;강경필;육형섭
    • 소성∙가공
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    • 제30권3호
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    • pp.142-148
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    • 2021
  • In hot forging analysis, the interfacial heat transfer coefficient (IHTC) is a very important factor defining the heat flow between the die and the material. In particular, in the hot forging analysis of aluminum 6xxx series alloy, which are used in automobile parts, differences in load and microstructure occur due to changes in surface temperature according to the IHTC. This IHTC is not a constant value but changes depends on pressure. This study derived the IHTC under low load using aluminum 6082 alloy. An experiment was performed by fabricating a compression die, and a heat transfer analysis was performed based on the experimental data. The heat transfer analysis used DEFORM-2D, a commercial finite element analysis program. To derive the IHTC, heat transfer analysis was performed for the IHTC in the range of 10 to 50 kW/m2℃ at intervals of 10kW/m2℃. The heat transfer analysis results according to the IHTC and the actual experimental values were compared to derive the IHTC of the aluminum 6082 alloy under low load.

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.

에너지 밀도 및 분말 증착 밀도를 고려한 직접 에너지 증착법 기반 Ti-6Al-4V 합금의 적층공정 최적화 (Additive Manufacturing Optimization of Directed Energy Deposition-Processed Ti-6Al-4V Alloy using Energy Density and Powder Deposition Density)

  • 이유경;김은성;천세호;설재복;성효경;오정석;김형섭;이태경;남태현;김정기
    • 한국분말재료학회지
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    • 제28권6호
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    • pp.491-496
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    • 2021
  • The process optimization of directed energy deposition (DED) has become imperative in the manufacture of reliable products. However, an energy-density-based approach without a sufficient powder feed rate hinders the attainment of an appropriate processing window for DED-processed materials. Optimizing the processing of DED-processed Ti-6Al- 4V alloys using energy per unit area (Eeff) and powder deposition density (PDDeff) as parameters helps overcome this problem in the present work. The experimental results show a lack of fusion, complete melting, and overmelting regions, which can be differentiated using energy per unit mass as a measure. Moreover, the optimized processing window (Eeff = 44~47 J/mm2 and PDDeff = 0.002~0.0025 g/mm2) is located within the complete melting region. This result shows that the Eeff and PDDeff-based processing optimization methodology is effective for estimating the properties of DED-processed materials.

Characterization of Anodized Al 1050 with Electrochemically Deposited Cu, Ni and Cu/Ni and Their Behavior in a Model Corrosive Medium

  • Girginov, Christian;Kozhukharov, Stephan;Tsanev, Alexander;Dishliev, Angel
    • Journal of Electrochemical Science and Technology
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    • 제12권2호
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    • pp.188-203
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    • 2021
  • The specific benefits of the modified films formed on preliminary anodized aluminum, including the versatility of their potential applications impose the need for evaluation of the exploitation reliability of these films. In this aspect, the durability of Cu and Ni modified anodized aluminum oxide (AAO) films on the low-doped AA1050 alloy was assessed through extended exposure to a 3.5% NaCl model corrosive medium. The electrochemical measurements by means of electrochemical impedance spectroscopy (EIS) and potentiodynamic scanning (PDS) after 24 and 720 hours of exposure have revealed that the obtained films do not change their obvious barrier properties. In addition, supplemental analyses of the coatings were performed, in order to elucidate the impact of the AC-deposition of Cu and Ni inside the pores. The scanning electron microscopy (SEM) images have shown that the surface topology is not affected and resembles the typical surface of an etched metal. The subsequent energy dispersive X-ray spectroscopy (EDX) tests have revealed a predominance of Cu in the combined AAO-Cu/Ni layers, whereas additional X-ray photoelectron (XPS) analyses showed that both metals form oxides with different oxidation states due to alterations in the deposition conditions, promoted by the application of AC-polarization of the samples.