• 제목/요약/키워드: Primary aluminum

검색결과 136건 처리시간 0.027초

분사주조한 과공정 Al-Si-Fe 합금의 기계적 및 열적 특성에 관한 고찰 (A Study on the Mechanical and Thermal Properties of Spray-cast Hypereutectic Al-Si-Fe Alloys)

  • 박재성;류민;윤의박;윤우영;김권희;김명호
    • 한국주조공학회지
    • /
    • 제26권3호
    • /
    • pp.123-128
    • /
    • 2006
  • Mechanical and thermal properties of spray-cast hypereutectic Al-20wt.%Si-xwt.%Fe alloys (x=0, 1, 3, 5) were investigated. After the spray-casting, hot extrusion was performed at $400^{\circ}C$. Intermetallic compound (${\beta}-Al_5FeSi$) and primary Si are observed in the spray-cast aluminum alloys. The size of primary Si and intermetallic compound of the spray-aluminum alloys became finer and more uniformly distributed than that of the permanent mold cast ones. Ultimate tensile strength of the spray-cast aluminum alloys increased by increasing Fe contents, but that of the permanent mold cast aluminum alloys decreased by increasing Fe contents possibly due to increased amount of coarse intermatallic compound. The coefficient of thermal expansion (CTEs) of the aluminum alloys became lower with finer primary Si and intermetallic compound, and this is attributed to the increased amount of interfacial area between the aluminum matrix and the phases of finer Si and intermetallic compound.

수평식 연속주조 시스템을 이용한 Al-xSi(x=10-15%)합금 수평연주에 관한 연구 (A study on the Horizontal Continuous Casting by Horizontal Continuous Casting Machine of Al-xSi(x=10-15%) Aluminum Alloy)

  • 서희식;하상백
    • 한국산업융합학회 논문집
    • /
    • 제17권3호
    • /
    • pp.122-135
    • /
    • 2014
  • This paper was studied on the horizontal continuous casting of Al-xSi(x=10~15%) aluminum alloy. The experiments of the horizontal continuous casting was carried out by the horizontal continuous casting machine for various casting conditions and investigated on fracture types and mechanisms. Surface defect types for the horizontal continuous casting is also investigated. And the study was carried out that the horizontal continuous casting conditions such as casting temperature, cooling rate, and drawing speed affect the hardness and primary silicon size of Al-xSi(x=10~15%) aluminum rod bar. Casting temperature within this experiment conditions don't affect on the hardness of rod bar but the higher casting temperature is the smaller primary silicon size. The higher cooling rate and drawing speed have the higher hardness and the smaller primary silicon size.

알루미늄 B390합금의 조직미세화에 미치는 Ca의 영향 (Effects of Ca on the Refinement of Microstructure in Aluminum B390 Alloy)

  • 김헌주
    • 한국주조공학회지
    • /
    • 제22권5호
    • /
    • pp.257-264
    • /
    • 2002
  • Effects of Ca content on the refinement of primary Si of Aluminum B390 alloy have been examined. Ca was found to have an effect on the refinement of primary Si particle. Primary Si particle size has been refined as Ca content of the melts decreased and cooling rate increased. A control of Ca content by the addition of $CuCl_2$ to the melt was the most efficient in the refinement of primary Si particles. The minimum size of primary Si particles in this study was $15.0\;{\mu}m$ when a residual content of Ca element in the alloy was 5ppm, Primary Si particle size was refined as primary Si crystallization temperature increased, which was attributed to the decrease of Ca content in the melts.

Transformation of Carboxylic Acids and Their Derivatives into Aldehydes by Lithium Tris(dialkylamino)aluminum Hydrides

  • Cha Jin Soon
    • Bulletin of the Korean Chemical Society
    • /
    • 제13권6호
    • /
    • pp.670-676
    • /
    • 1992
  • A systematic study of the partial reduction of carboxylic acids and their derivatives to the corresponding aldehydes with lithium tris(dialkylamino)aluminum hydrides under practical conditions has been carried out. The diethylaminosubstituted derivative of lithium aluminum hydride, lithium tris(diethylamino)aluminum hydride (LTDEA), shows quite general applicability in the conversion of carboxylic acids, carboxylic esters, and primary carboxamides to the corresponding aldehydes. Lithium tripiperidinoaluminum hydride (LTPDA) also appears to be a reagent of choice for such partial transformation of primary carboxamides. In additioin, both LTDEA and LTPDA reduce tertiary carboxyamides to aldehydes in high yields. Finally, lithium tris(dihexylamino)aluminum hydride (LTDHA) is capable of achieving the chemoselective reduction of aromatic nitriles to aldehydes in the presence of aliphatic nitriles under practical conditions.

알루미늄의 리사이클링 기술 (Recycling Technologies of Aluminum)

  • 손호상
    • 자원리싸이클링
    • /
    • 제28권2호
    • /
    • pp.3-13
    • /
    • 2019
  • 알루미늄은 지각 구성 원소 중 실리콘에 이어 두 번째로 풍부한 금속원소이다. 알루미늄은 가볍고, 전기전도도가 우수하고, 내식성이 우수하지만 산소와의 친화력이 강한 특성을 가지고 있다. 그러나 알루미늄의 1차 지금을 제조하기 위해서는 다량의 에너지를 소비한다. 한편 알루미늄 스크랩을 리사이클링하면 1차 지금 생산과 비교하여 에너지 및 환경부하를 저감할 수 있다. 그러나 알루미늄 스크랩 중의 불순물 제거가 곤란하여 재생되는 양은 한정되어 있다. 본 논문에서는 알루미나의 제조부터 스크랩 처리 및 용융까지의 알루미늄 생산 및 리사이클링 공정에 대하여 고찰하였다.

초음파 용탕처리를 이용한 알루미늄 피스톤의 조직 미세화 (Refinement of Microstructures for Aluminum Piston through Ultrasonic Melt Treatment)

  • 이상화;정재길;이정무;조영희;윤운하;안용식;윤동춘;이정근;류관호
    • 한국주조공학회지
    • /
    • 제36권2호
    • /
    • pp.53-59
    • /
    • 2016
  • The effects of ultrasonic melt treatment on the microstructures of aluminum piston were examined at five observation parts having different cooling rates. The microstructure of aluminum piston consisted of primary Si, eutectic Si, and various types of intermetallic compounds. Regardless of cooling rate, the ultrasonic melt treatment transformed dendritic eutectic cells to equiaxed eutectic cells and it decreased the sizes of eutectic Si and intermetallic compounds that exist at eutectic cell boundaries. In the absence of ultrasonic treatment, coarse primary Si particles were severely segregated and its size was increased with decreasing the cooling rate. The ultrasonic treatment decreased the size of primary Si particles from $25.5{\sim}31.0{\mu}m$ to $17.6{\sim}23.1{\mu}m$, depending on the cooling rate. In the presence of ultrasonic treatment, relatively fine primary Si particles were homogeneously distributed throughout the piston. In addition, the ultrasonic treatment increased the population density and area fraction of fine primary Si particles.

B.390 알루미늄 합금의 마모특성에 미치는 초정Si 입자크기와 잔류응력의 영향 (Effect of Primary Si size and Residual Stress on the Wear Properties of B.390 Al Alloys)

  • 김헌주;김성재
    • 열처리공학회지
    • /
    • 제19권1호
    • /
    • pp.20-29
    • /
    • 2006
  • Wear behaviour of B.390 aluminum alloy with different particle sizes of primary Si against a SM45C counterface was studied as a function of wear load and sliding velocity, using pin-on-disk apparatus under dry condition. The wear rate of specimen with fine primary Si particles showed increased wear resistance at high wear load, on the other side wear resistance of coarse primary Si particle size was improved at low wear load. As the compressive residual stress in the matrix increased remarkably by liquid nitrogen(LN) treatment, wear resistance of the LN treated specimen was more excellent than that of T6 treated specimen.

자동차 부품용 과공정 알루미늄 합금의 기계적 특성 (Mechanical Properties of Hyper-Eutectic Aluminum Alloys for Automobile Parts)

  • 배철홍;김종명
    • 한국자동차공학회논문집
    • /
    • 제18권1호
    • /
    • pp.120-126
    • /
    • 2010
  • It was known that the excellent wear resistance of hyper eutectic aluminum alloy is based on the primary Si particles which are distributed in the base metal. When the primary Si volume fraction increases, the smaller size have excellent wear resistance characteristics. However, this trend always does not match. There is no investigation result based on the materials and methods for real using parts. In this study, using the automotive parts manufacturer currently in use hyper eutectic Al alloy tensile test specimen type sample was fabricated by 350Ton high pressure die-casting machine. Then, fluidity, tensile, impact and wear resistance properties were evaluated. If the casting quality, primary Si size, fraction and distribution are similar, mechanical properties and wear resistance are equivalent.

B390 알루미늄 합금의 초정Si 입자분포에 미치는 원심주조 공정인자의 영향 (Effect of Centrifugal Casting Parameters on The Distribution of Primary Si Particles of B390 Aluminum Alloy)

  • 박정욱;김헌주
    • 한국주조공학회지
    • /
    • 제28권1호
    • /
    • pp.25-30
    • /
    • 2008
  • To develop a functionally graded microstructure of cylindrical liner, effect of centrifugal casting parameters such as pouring temperature of hyper-eutectic Al-Si alloy melt, mold pre-heating temperature, and rotational frequency of mold on distribution of primary Si particles across wall thickness were investigated. Segregation tendency of Si particles toward inner side of cylindrical liner increased as the increase of rotational frequency of mold, pouring temperature of melt and mold pre-heating temperature. Especially, distribution density of primary Si particles within 1.5 mm from inner surface of cylindrical liner was above 35% under the centrifugal casting condition of $750^{\circ}C$ melt pouring temperature, $300^{\circ}C$ mold pre-heating temperature, and 2500 rpm mold rotational frequency.

Reaction of Lithium Tris(diethylamino)aluminum Hydride in Tetrahydrofuran with Selected Organic Compounds Containing Representative Functional Groups

  • Jin Soon Cha;Jae Cheol Lee
    • Bulletin of the Korean Chemical Society
    • /
    • 제14권4호
    • /
    • pp.469-475
    • /
    • 1993
  • The approximate rates and stoichiometry of the reaction of excess lithium tris(diethylamino)aluminum hydride (LTDEA) with selected organic compounds containing representative functional groups under standardized condition (tetrahydrofuran, 0$^{\circ}C$) were examined in order to define the characteristics of the reagent for selective reductions. The reducing ability of LTDEA was also compared with those of the parent lithium aluminum hydride (LAH) and lithium tris(dibutylamino)aluminum hydride (LTDBA). In general, the reactivity toward organic functionalities is in order of LAH${\gg}$LTDEA${\geq}$LTDBA. LTDEA shows a unique reducing characteristics. Thus, benzyl alcohol and phenol evolve hydrogen slowly. The rate of hydrogen evolution of primary, secondary, and tertiary alcohols is distinctive: 1-hexanol evolves hydrogen completely in 6 h, whereas 3-hexanol evolves hydrogen very slowly. However, 3-ethyl-3-pentanol does not evolve any hydrogen under these reaction conditions. Primary amine, such as n-hexylamine, evolves only 1 equivalent of hydrogen. On the other hand, thiols examined are absolutely inert to this reagent. LTDEA reduces aldehydes, ketones, esters, acid chlorides, and epoxides readily to the corresponding alcohols. Quinones, such as p-benzoquinone and anthraquinone, are reduced to the corresponding diols without hydrogen evolution. However, carboxylic acids, anhydrides, nitriles, and primary amides are reduced slowly, where as tertiary amides are readily reduced. Finally, sulfides and sulfoxides are reduced to thiols and sulfides, respectively, without evolution of hydrogen. In addition to that, the reagent appears to be an excellent partial reducing agent to convert esters, primary carboxamides, and aromatic nitriles into the corresponding aldehydes. Free carboxylic acids are also converted into aldehydes through treatment of acyloxy-9-BBN with this reagent in excellent yields.