• 제목/요약/키워드: AZ31B Magnesium Alloy Sheet

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AZ31 마그네슘 합금판재의 소성변형특성 (Plastic Deformation Characteristic of AZ31 Magnesium alloy Sheet)

  • 박진기;김영석;;유봉선
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2005년도 춘계학술대회 논문집
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    • pp.64-68
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    • 2005
  • In recent years, there has been a growth of the manufacture and application of magnesium products because of its small specific gravity as well as its relatively high strength. However, there are so many studies to assure good formability because magnesium sheet alloy is difficult to form. In this study, uniaxial tensile and biaxial tensile test of AZ31 magnesium sheet alloy with thickness of 1.2mm were performed at room temperature. Uniaxial tensile test were performed until $7\%$ of engineering strain. R-values and stress-strain curve were obtained. Biaxial tensile tests with cruciform specimen were performed until the breakdown of the specimen occurs. The yield loci are made by application of plastic work theory. The results are compared with the theoretical predictions based on the Hill and Logan-Hosford model. However, next study will be performed at warm-temperature because the specimens are broken under the $0.5\%$ of equivalent strain at biaxial tensile test.

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AZ31B 마그네슘합금 판재의 원형 및 사각 딥드로잉 성형성의 실험적 평가 (A Study on the Experimental Evaluation of AZ31B Sheet Formability with Circle and Rectangle Shape)

  • 권기태;강석봉;강충길
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2007년도 추계학술대회 논문집
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    • pp.250-253
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    • 2007
  • Since Mg alloy has many attractive advantages among the practically used metals, many researchers have been studied to develop useful process and material. The crystal structure of Magnesium was hexagonal close-packed, so its formability was poor at room temperature. But formability was improved in high temperature with increasing of slip planes, twins, dynamic recrystallization. In this study The formability of AZ31B magnesium sheet is estimated according to the variable temperatures, forming speed, thickness, blank holding force. The results of deep drawing experiences show that the formability is well at the range from 200 to $250^{\circ}C$, 20 to 60 mm/min forming speed and 2.5 to 3KN blank holding force.

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AZ31B 마그네슘 합금 판재에 대한 드로우벤드 시험과 스프링백 측정 (Measurement of Springback of AZ31B Mg Alloy Sheet in Draw/bend Test)

  • 최종길;이명규;김헌영
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2007년도 춘계학술대회 논문집
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    • pp.302-305
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    • 2007
  • The springback characteristics of AZ31B magnesium alloy sheet was investigated in OSU draw/bend test. Springback is the elastically-driven change of shape of a part after forming and it should be estimated and controlled to manufacture more precise products in sheet forming. The demands are increasing for magnesium alloy sheet press forming, but the study on its springback characteristics is insufficient. Strip draw/bend tests were conducted with various conditions - die radius, sheet thickness and controlled tensile force. The springback angles were measured from 'sidewall curl' of deformed shape. The tendency of springback angle was observed from the tests.

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AZ31B 마그네슘 합금 판재의 구성식 개발 (Constitutive Modeling of AZ31B Magnesium Alloys)

  • 이명규;정관수;김헌영
    • 소성∙가공
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    • 제16권4호
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    • pp.234-238
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    • 2007
  • Magnesium alloy sheets in room temperature have unusual mechanical properties such as high in-plane anisotropy/asymmetry of yield stress and hardening behavior. In this paper, the continuum plasticity models considering the plastic behavior of AZ31B Mg alloy sheet were derived. A new hardening law based on modified two-surface model was developed to consider the general stress-strain response of metals including Bauschinger effect, transient behavior and the unusual asymmetry. Three deformation modes observed during the continuous tension/compression tests were mathematically formulated with simplified relations between the state of deformation and their histories. To include the anisotropy and asymmetry of the initial yield stress, the Drucker-Prager's pressure dependent yield surface was modified by adding anisotropic constants.

레이저 열원을 이용한 마그네슘 합금의 용접성에 관한 연구 (II) - AZ31B-H24 및 AZ31B-O 레이저 용접부의 기계적 특성 - (A Study on the Weldability of Magnesium Alloy by Laser Heat Source (II) - Mechanical Properties of laser-welded AZ31B-H24 and AZ31B-O -)

  • 이정한;김종도;이문용
    • Journal of Welding and Joining
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    • 제30권6호
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    • pp.56-61
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    • 2012
  • Magnesium alloy sheet which is commercially available in the market presently is AZ31B, a Mg-Al-Zn three elements alloy. AZ31B is used by being classified into AZ31B-H24 and AZ31B-O depending on temper designation. In this study, AZ31B-H24 and AZ31B-O alloy sheets with 1.25mm thickness were butt-welded using CW Nd:YAG laser. And the effect of materials on mechanical properties was investigated by tensile and hardness tests. As a result of this study, regardless of materials, the butt-welded joint did not show a significant difference in tensile strength and hardness values. However, compared with the basemetal, the AZ31B-O showed more outstanding mechanical properties than AZ31B-H24, and that is because H24 material lost the effect of work hardening during welding.

마그네슘 합금 판재를 활용한 차체 Reinforced Dash 부품 온간성형 공정 연구 (A Study on Warm Forming Technology of Car Body Reinforced Dash Using Magnesium Alloy Sheet)

  • 박동환;탁윤학
    • 한국생산제조학회지
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    • 제23권5호
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    • pp.519-524
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    • 2014
  • The use of light weight magnesium alloy offers significant potential towards improvement of the automotive fuel efficiency. However, the application of formed magnesium alloy components in auto-body structures is restricted due to the low formability at room temperature and lack of knowledge for processing magnesium alloys at elevated temperatures. In this study, a warm tensile test of magnesium alloys was performed to measure tensile strength and elongation. An improvement in formability was confirmed at increased temperatures above about $250^{\circ}C$. Car body warm forming technology was conducted for forming forming reinforced dash components of the magnesium alloy AZ31B sheet at elevated temperatures.

AZ31B 마그네슘 합금판재의 성형특성 평가를 위한 실험적·해석적 연구 (Experimental and Analytical Evaluation of Forming Characteristics for AZ31B Magnesium Alloy Sheet)

  • 이명근;김형종
    • 소성∙가공
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    • 제20권2호
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    • pp.146-153
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    • 2011
  • This study aimed at providing an experimental database for the mechanical properties of AZ31B magnesium alloy sheet such as stress-strain curve, yield stress, R-value and forming limit diagram(FLD) at various strain-rates and temperatures. Tensile tests were carried out on specimens having the orientations of $0^{\circ}$, $45^{\circ}$ and $90^{\circ}$ to the rolling direction with different crosshead speeds in the range between 0.008 and 8 mm/s at temperature from 25(room temperature) to $300^{\circ}C$. The influence of the specimen gage length on the tensile properties was investigated. FLD tests were performed at punch speed of 0.1 and 1.0 mm/s in the same temperature range as that of the tensile tests. Swift cup tests were conducted to verify the usefulness of the material database and the reliability of the finite element analysis(FEA). The effects of strain-rate as well as temperature were taken into account in these simulations. It was shown that the FLD-based failure was reasonably well predicted by the thermal-deformation coupled analysis for this rate-sensitive material.

십자 형상 금형의 디프 드로잉에서 AZ31B 마그네슘 합금판재의 성형 한계 (Forming Limit of AZ31B Magnesium Alloy Sheet in the Deep Drawing with Cross Shaped Die)

  • 황상희;최선철;김헌영;김형종;홍석무;신용승;이근호
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2008년도 춘계학술대회 논문집
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    • pp.374-377
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    • 2008
  • Magnesium alloy sheets are usually formed at temperatures between $150^{\circ}C$and $300^{\circ}C$ because of their poor formability at room temperature. In the present study, the formability of AZ31B magnesium alloy sheets was investigated by the analytical and experimental approaches. First, tensile tests and the limit dome height test were carried out at elevated temperatures to get the mechanical properties and forming limit diagram, respectively. And then deep drawing of cross shaped die was tried to get the minimum corner radius and forming limit at specific temperature. Blank shape, punch velocity, minimum corner radius, fillet size, etc, were determined by finite element analysis physical try-outs. Especially, optimum punch and die temperature were suggested through the temperature-deformation analysis using Pam-stamp.

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마그네슘합금의 온간 딥 드로잉 공정에서의 윤활 특성 연구 (A study on lubrication characteristics in warm deep drawing of magnesium alloy sheet)

  • 박설희;김상우;이영선;김병민;이정환
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2007년도 추계학술대회 논문집
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    • pp.306-309
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    • 2007
  • Recently, magnesium alloys have been widely used in automotive, aerospace and electronic industries with the advantages such as lightweightness, high specific strength and stiffness. However, magnesium alloy has quite low formability at room temperature due to its hexagonal close-packed crystal structure. Warm deep drawing is one of the forming technologies to improve the formability of magnesium alloy sheet and the lubrication condition is an important process parameter in that. In this study, the drawing tests of AZ31 alloy sheet at elevated temperature for various kinds of lubricant were carried out and the effects of lubrication conditions on drawbility were investigated.

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AZ31 마그네슘 합금판재의 소성변형특성 (Plastic Deformation Characteristic of AZ31 Magnesium Alloy Sheet)

  • 박진기;;유봉선;김영석
    • 소성∙가공
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    • 제14권6호
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    • pp.520-526
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    • 2005
  • In recent years, there has been a growth of the manufacture and application of magnesium products because of its small specific gravity as well as its relatively high strength. However, there are so many studies to assure good formability because magnesium sheet alloy is difficult to form. In this study, uniaxial tensile and biaxial tensile tests of AZ31 magnesium sheet alloy with thickness of 1.2mm were performed at room temperature. Uniaxial tensile tests were performed until $7{\%}$ of engineering strain. Lankford values and stress-strain curve were obtained. Biaxial tensile tests with cruciform specimen were performed until the breakdown of the specimen occurs. The yield loci were calculated by application of plastic work theory. The results are compared with the theoretical predictions based on the Hill and Logan-Hosford model. In this study, Hill's 1979 yield function for the case of m=2.8 and Logan-Hosford yield function for the case of M=8 give good agreements with experimental results. However, next study will be performed at warm-temperature because the specimens are broken under the $0.5{\%}$ of equivalent strain at biaxial tensile test.