• Title/Summary/Keyword: AC7A 알루미늄 합금

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Numerical Study on Thermal Deformation of AC4C and AC7A Casting Material (AC4C와 AC7A 주조재의 열변형 수치해석적 연구)

  • Yoon, Hee-Sung;Oh, Yool-Kwon
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.20 no.5
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    • pp.541-546
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    • 2011
  • This study was numerically investigated on thermal deformation of AC4C and AC7A aluminum alloy casting material for manufacturing the automobile tire mold. The metal casting device was used in order to manufacture the mold product of automobile tire at the actual industrial field. The temperature distribution and the cooling time of these materials were numerically calculated by finite element analysis. Thermal deformation with stress distribution was also calculated form the temperature distribution results. The thermal deformation was closely related to the temperature difference between the surface and inside of the casting. As shown by numerical analysis result, the thermal deformation of AC7A casting material became higher than AC4C casting material. In addition, the results of displacement and stress distributions appeared to be larger at the center parts of casting than on its sides because of the shrinkage caused by the cooling speed difference.

A Study on the Development for the Vehicle Engine Mountion Bracket Using Squeeze Casting (스퀴즈 캐스팅 제조법에 의한 자동차 엔진 마운틴 브래킷 개발에 관한 연구)

  • Kim, S.H.
    • Journal of Power System Engineering
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    • v.7 no.4
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    • pp.44-48
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    • 2003
  • Alumium alloys casting are gaining increased acceptance in the automotive and electronic industeries and squeeze casting is the most efficient method of manufacturing such mass produced parts. This study has been investigated the microstructures and mechanical properties of Al-7.0Si-0.4Mg(AC4C)alloy fabricated by squeeze casting process for development of Engine Mountain Bracket. The microstructure of squeeze casted specimen were composed of eutectic structure Alumimim solid solution and $Mg_2Si$ precipitates. The tensile strength of as-solid solution treatment Al-7.0Si-0.4Mg alloy revealed 2985MPa. It was found that Al-7.0Si-0.4Mg alloy have good aging hardening effect results are presented to show the validity of the control method.

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A Study on the Preparation and Wear Characteristics of TiC Hardfaced Layers on Aluminium alloy by PTA Method (PTA법에 의한 TiC 분말 표면강화 AL 합금층의 제조 및 마모특성에 관한 연구)

  • 민준원;유승을
    • Transactions of the Korean Society of Automotive Engineers
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    • v.7 no.9
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    • pp.138-145
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    • 1999
  • Surface hardening of AC4C aluminium alloy with TiC powders was obtained by plasma transferred are (PTA) method, Bead appearance, microstrucutre and wear behavior were characterized in relation to the torch current, powder feed rate and wear condition. The width and the depth of bead were mainly increased with increasing torch current. The comparison of wear behavior between AC4C alloy and PTA treated AC4C alloy showed the remarkable enhancement of wear resistance.

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A Study on Solidification Characteristics of Aluminum Alloy Casting Material by Pre-heated Temperature Conditions (예열온도조건에 따른 알루미늄 합금 주조재의 응고특성에 관한 연구)

  • Yoon, Cheonhan;Yoon, Heesung;Oh, Yoolkwon
    • Journal of the Korean Society of Safety
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    • v.27 no.4
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    • pp.7-12
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    • 2012
  • In this study, the solidification characteristics inside the AC7A casting material was analyzed using the numerical analysis method and was verified using the experimental method by the pre-heated temperature conditions of metal casting device. For the numerical analysis, "COMSOL Multiphysics", the commercial code based on the finite element analysis(FEA), was used in order to predict the thermal deformation of the AC7A casting material including temperature, displacement and stress distribution. Also, in order to verify the results calculated by the numerical analysis, the experiment for temperature measurement inside the AC7A casting material was performed using the K-type thermocouple under the same condition of numerical analysis method. In the numerical results, thermal deformation inside AC7A casting material was well-suited for manufacturing products when the pre-heated temperatures of the metal casting device was $250^{\circ}C$. When the results of the temperature distribution were experimentally measured and were compared with those of the numerical result, it appeared that there was some temperature difference because of the latent heat by phase change heat transfer. However, the result of cooling temperature and patterns were almost similar except for the latent heat interval. The solidification characteristics was closely related to the temperature difference between the surface and inside of the casting.

Hardening Characteristics of Aluminum Alloy Surface by PTA Overlaying with Metal Powders (I) (플라즈마분체 오버레이법에 의한 알루미늄합금 표면의 경화특성에 관한 연구(I) -후막 표면 합금화층의 형성조건과 그 조직-)

  • ;中田一博;;;松田福久
    • Journal of Welding and Joining
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    • v.12 no.4
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    • pp.85-101
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    • 1994
  • Effect of Cr, Cu and Ni metal powders addition on the alloyed layer of aluminum alloy (AC2B) has been investigated with the plasma transferred arc (PTA) overlaying process. The overlaying conditions were 125-200A in plasma arc current, 150mm/min in process speed and 5-20g/min in powder feeding rate. Main results obtained are summarized as follows: 1) It was made clear that formation of thick surface alloyed layer on aluminum alloy is possible by PTA overlaying process. 2) The range of optimum alloying conditions were much wider in case of Cu and Ni powder additions than the case of Cr powder addition judging from the surface appearance and the bead macrostructure. 3) Alloyed layer with Cu showed almost the homogeneous microstructure through the whole layer by eutectic reaction. alloyed layers with Cr and Ni showed needle-like and agglomerated microstructures, the structure of which has compound layer in upper zone of bead by peritectic and eutectic-peritectic reactions, respectively. 4) Microconstituents of the alloyed layer were analyzed as A1+CrA $l_{7}$ eutectics, C $r_{2}$al sub 11/, CrA $l_{4}$, C $r_{4}$A $l_{9}$ and C $r_{5}$A $l_{*}$ 8/ for Cr addition, Al+CuA $l_{2}$(.theta.) eutectics and .theta. for Cu addition, and Al+NiA $l_{3}$ eutectics. NiA $l_{3}$, N $i_{2}$A $l_{3}$ and NiAl for Ni addition. 5) Concerning defect of the alloyed layer, many blow holes were seen in Cr and Ni additions although there was lesser in Cu addition. Residual gas contents in blow hole for Cu and Ni alloyed layer were confirmed as mainly $H_{2}$ and a littie of $N_{2}$ Cracking was observed in compound zone of the alloyed layer in case of Cr and Ni addition but not in Cu alloyed layer.r.r.

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Effect of Mold Preheat Temperature on Solidification Crack Strength of AC2B Aluminum Alloy (AC2B 알루미늄 주조합금의 응고균열 강도에 미치는 금형 예열온도의 영향)

  • Kim, Heon-Joo
    • Journal of Korea Foundry Society
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    • v.34 no.5
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    • pp.162-169
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    • 2014
  • The effect of the mold preheat temperature on the solidification crack strength was investigated in AC2B aluminum alloy. A tension type apparatus as part of a solidification crack test which could measure the stress-strain relationship quantitatively was utilized. The evaluation of the solidification crack strength with varying mold preheat temperatures was performed by the test procedure established in this research. When the mold preheat temperatures were $250^{\circ}C$, $150^{\circ}C$ and $50^{\circ}C$, the solidification crack strengths were found to be $7.8Kgf/cm^2$, $12.9Kgf/cm^2$ and $28.6Kgf/cm^2$, respectively. In the same way, when the mold preheat temperatures were $250^{\circ}C$, $150^{\circ}C$ and $50^{\circ}C$, the corresponding temperatures of the failure sites were $610^{\circ}C$, $600^{\circ}C$ and $571^{\circ}C$, and the calculated solid fractions were 14.0%, 29.3% and 50.8% when the specimens failed, respectively. The solidification crack strength increased in proportion to the solid fraction of the failure site. The solidification crack strength obtained in this test is assumed to reflect the effects of metallurgical factors on the thermo-plastic characteristics of a solidifying alloy such as the grain size of the solid, the grain morphology, and the distribution of solid grain.

Effect of Sr and (Ti-B) Additives on Tensile Properties of AC4A Recycled Aluminum Casting Alloys (재활용 AC4A 알루미늄 합금의 인장특성에 미치는 (Ti-B), Sr 첨가제의 영향)

  • Oh, Seung-Hwan;Kim, Heon-Joo
    • Journal of Korea Foundry Society
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    • v.38 no.5
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    • pp.87-94
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    • 2018
  • The effects of Sr and (Ti-B) additives on the tensile properties of AC4A recycled (35% scrap content) aluminum alloys were investigated. An acicular morphology of the eutectic Si phase of as-cast specimens was converted to a fibrous morphology upon the addition of Sr. Moreover, morphology of the Sr modified eutectic Si phase became finer due to a T6 heat treatment. The grain size of the ${\alpha}$-solid solution was decreased by the addition of (Ti-B) additives. Depending on the treatment conditions of the as-cast specimens, i.e., no addition, a Sr addition and a (Ti-B)+Sr addition, the tensile strength levels of the as-cast specimens were 182, 192, and 204MPa, respectively. The corresponding strengths of T6 heat-treated specimens were 293, 308, and 318MPa. Elongations of the as-cast specimens were 2.2, 3.1, and 5.6%, and the corresponding elongations of the T6 heat-treated specimens were 4.6, 6.1, and 7.6%. The percentage of the reduced section area in the tensile specimens was also increased by the Sr and (Ti-B) additives. Sr and (Ti-B) additives changed the microstructure and the distribution of defects in the castings, resulting in an improvement of the tensile properties of AC4A aluminum alloys. According to our test results, recycled (35% scrap content) AC4A aluminum alloy met all of the KS requirements of the tensile strength and elongation values of AC4A aluminum alloy except for the elongation value of the one specimen condition, in this case the as-cast no-addition condition.

Development of Aluminium Alloy for Piston of Air Compressor (공기 압축기의 피스톤용 알루미늄 합금 소재 개발)

  • Kim, Soon-Kyung;Kim, Moon-Kyung
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.7 no.1
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    • pp.9-16
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    • 2008
  • It is important not only to reduce the casting defects of piston but also to improvement in the mechanical properties(hardness) of piston for the air compressor. The blow hole is typical casting defects in the conventional cast of aluminium alloy(AC8A-T6) piston. Because of the heat treatment method, mechanical properties of the aluminium alloy for piston was decided on the heat treatment method and cycle. Therefore, we tested on the development of mechanical properties and on the casting defects of piston for the air compressor in accordance with the heat treatment and casting condition. After the heat treatment and casting was carried out as several times, and was compared with the imported piston. As a result of several investigations; microstructure, hardness and casting defects of piston was changed under the influence of the heat treatment and casting method. When the cooling rate was controlled and the uni-cast method used, it bas the same mechanical properties and microstructure.

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Effect of Scrap Addition Ratio on Tensile and Solidification Cracking Properties of AC4A Aluminum Casting Alloy (AC4A 알루미늄 합금의 인장 및 응고균열 특성에 미치는 스크랩 첨가 비율의 영향)

  • Oh, Seung-Hwan;Kim, Heon-Joo
    • Journal of Korea Foundry Society
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    • v.40 no.3
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    • pp.85-96
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    • 2020
  • The effect of an aluminum scrap addition ratio on the tensile and solidification cracking properties of the AC4A aluminum alloy in the as-cast state and heat-treated state were investigated in this study. Generally, the expected problem of using scrap in aluminum casting is an increase of hydrogen and Fe element inside the aluminum melt. Another issue is an oxide film which has a weak interface with the molten aluminum and acts as potent nucleation sites for internal porosity and crack initiation. Solidification cracking is one of the critical defects that must be resolved to produce high quality castings. A conventional evaluation method for solidification cracking is a relative and qualitative analysis method which does not provide quantitative data on the thermal stress in the solidification process. Therefore, a newly designed solidification cracking test apparatus was used in this study, and the device can provide quantitative data. As a result, after conducting experiments with different scrap addition ratios (0%, 20%, 35%, 50%), the tensile strengths and elongations in the as-cast state were 214, 187.7, 182.1 and 170.4MPa and 4.6%, 3.4%, 3.1% and 2.3%, respectively. In the case of the T6 heat-treated state, the tensile strengths and elongations were 314.9, 294.6, 293.1 and 271.1MPa and 5.4%, 4.6%, 3.8% and 3.1%, respectively. The strength of the solidification cracking was 3.1, 2.4, 2.2and 1.6MPa as the scrap addition ratio increases.