• Title/Summary/Keyword: Magnesium sheet

Search Result 155, Processing Time 0.027 seconds

Forming Analysis for Warm Deep Drawing Process of Magnesium Alloy Sheet (마그네슘 합금 판재의 온간 딥드로잉 공정의 성형해석)

  • Lee, M.H.;Kim, H.Y.;Kim, H.J.;Kim, H.K.;Oh, S.I.
    • Transactions of Materials Processing
    • /
    • v.16 no.5 s.95
    • /
    • pp.401-405
    • /
    • 2007
  • Due to the low densities and high specific strength and stiffness, magnesium alloy sheets are very attractive lightweight materials for automotive and electrical products. However, the magnesium alloy sheets should be usually formed at elevated temperature because of their poor formability at room temperature. For the use of the magnesium alloy sheets for an industrial, their mechanical properties at elevated temperature and appropriate forming process conditions have to be developed. In this study, non-isothermal simulation of a square cup drawing of magnesium alloy sheets have been conducted to evaluate a proper forming process conditions such as the tool temperature, the tool shoulder radius, friction between the blank and the tools. According to this study, appropriate forming process conditions of square cup drawing at elevated temperature from magnesium alloy sheets are suggested.

Evaluation of Mechanical Properties of AZ31B for Sheet Metal Forming at Warm and High Temperature (온간, 열간 판재 성형을 위한 AZ31B의 기계적 성질 평가)

  • Choo D. K.;Kim W. Y.;Lee J. H.;Kang C. G.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
    • /
    • 2004.10a
    • /
    • pp.256-259
    • /
    • 2004
  • In the present study, AZ31B sheets has a bad formability in room temperature, but the formability is improved significantly as increasing the temperature because of rolled magnesium alloy sheet has a hexagonal closed packed structure (HCP) and a plastic anisotropy. In this paper, after tensile test in various temperatures, strain rate, show the tensile mechanical properties, yield and ultimate strength, K-value, work hardening exponent(n), strain rate sensitivity(m). As temperature increased, yield, ultimate strength and K-value, work hardening exponent(n) are decreased but strain rate sensitivity(m) is increased. As cross-head-speed increased, yield, ultimate strength and K-value, work hardening exponent(n) are increased. And according to the temperature, how change the plastic anisotropy factor R. In addition, we observed how temperatures and cross-head-speed effect on microstructure.

  • PDF

Formability Test in Warm Forming Simulation of Magnesium Alloy Sheet Using FLD (마그네슘 합금 판재의 온간성형 해석에서 FLD를 이용한 성형성 평가)

  • Lee, M.H.;Kim, H.K.;Kim, H.K.;Oh, S.I.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
    • /
    • 2008.05a
    • /
    • pp.556-559
    • /
    • 2008
  • In this study, the failure in circular cup deep drawing simulation at warm temperature is predicted using forming limit diagram (FLD). The FLD is used in sheet metal forming analysis to determine the criterion for fracture prediction. The simulation with heat transfer of circular cup deep drawing at warm temperature was conducted. To predict the failure, the simulation with heat transfer used FLD at temperature in the vicinity of maximum thinning. The result of the simulation with heat transfer shows that the drawn depth increases with increasing temperature and is in accord with the experimental results above $150^{\circ}C$. The FLD provides a good guide for the failure prediction of warm forming simulation with heat transfer.

  • PDF

Heating and Cooling Channel Design of Cross-Shaped Die for Warm Forming of Magnesium Alloy Sheet (Mg 온간성형을 위한 십자형상 금형의 가열/냉각 채널 설계)

  • Choi, S.C.;Ko, D.S.;Kim, H.Y.;Kim, H.J.;Hong, S.M.;Ryu, S.Y.;Shin, Y.S.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
    • /
    • 2008.05a
    • /
    • pp.370-373
    • /
    • 2008
  • It is known that the temperatures of die, punch, holder and punch pad need to be kept different to get better formability in Mg sheet forming processes. Heating and cooling channels are usually equipped in each tool to assign different temperature. This study focused on the optimal design of the heating and cooling channels for a cross-shaped deep drawing die set. While the die and blankholder were heated to and kept at $250^{\circ}C$ by using heat cartridges, the punch and punch pad were kept at much lower temperature than that of the die and blankholder by water circulating through cooling channels. All the approaches were done by numerical analyses, aiming to maximize the cup height and to minimize the punch corner radius without any failure.

  • PDF

Temperature and Strain Rate Dependent Tension Properties of Stainless Steel-Aluminum-Magnesium Multilayered Sheet Fabricated by Roll Bonding (롤 아연된 STS-Al-Mg 이종금속판재의 온도와 변형률속도에 따른 1축인장 변형특성)

  • Hwang, B.K.;Lee, K.S.;Hong, S.E.;Lee, Y.S.
    • Transactions of Materials Processing
    • /
    • v.20 no.3
    • /
    • pp.257-264
    • /
    • 2011
  • Multilayer(clad) sheets, composed of two or more materials with different properties, are fabricated using the roll-bonding process. A good formability is an essential property for a multilayered sheet in order to manufacture parts by plastic deformation. In this study, the influences of temperature and strain rate on the plastic properties of stainless steel-aluminum-magnesium multilayered(STS-Al-Mg) sheets were investigated. Tensile tests were performed at various temperatures and strain rates on the multilayered sheet and on each separate layer. Fracture of the multilayered sheet was observed to be temperature-dependent. At the base temperature of $200^{\circ}C$, all materials fractured simultaneously. At lower temperatures, the Mg alloy sheet fractured earlier than the other materials. Conversely, the other materials fractured earlier than the Mg alloy sheet at higher temperatures. The uniform and total elongations of the multilayered sheet were observed to be higher than that of each material at a temperature of $250^{\circ}C$. Larger uniform elongations were obtained for higher strain rates at constant temperature. The same trend was observed for the Mg alloy sheet, which exhibited the lowest elongation among the three materials. The tensile strengths and elongations of the single layer sheets were compared to those of the multilayer material. The strength of the multilayered sheet was successfully calculated by the rule of mixture from the values of each single layer. However, no simple correlation between the elongation of each layer and that of the multilayer was obtained.

Prediction for Thickness and Fracture of Stainless Steel-Aluminum-Magnesium Multilayered Sheet during Warm Deep Drawing (온간 딮 드로잉에서 이종금속판재(STS430-Al3004-AZ31)의 파단 및 두께 예측을 위한 연구)

  • Lee, Y.S.;Lee, K.S.;Kim, D.
    • Transactions of Materials Processing
    • /
    • v.21 no.1
    • /
    • pp.49-57
    • /
    • 2012
  • It is difficult to estimate the properties of multilayered sheet because they are composed of one or more different materials. Plastic deformation behavior of the multilayered sheet is quite different as compared to each material individually. The deformation behavior of multilayered sheet should be investigated in order to prevent forming defects and to predict the properties of the formed part. In this study, the mechanical properties and formability of stainless steel-aluminum-magnesium multilayered sheet were investigated. The multilayered sheet needs to be deformed at an elevated temperature because of its poor formability at room temperature. Uniaxial tensile tests were performed at various temperatures and strain rates. Fracture patterns changed mainly at a temperature of $200^{\circ}C$. Uniform and total elongation of multilayered sheet increased to values greater than those of each material when deformed at $250^{\circ}C$. The limiting drawing ratio (LDR) was obtained using a circular cup deep drawing test to measure the formability of the multilayered sheet. A maximum value for the LDR of about 2 was achieved at $250^{\circ}C$, which is the appropriate forming temperature for the Mg alloy. Fracture patterns on a circular cup and thickness of formed part were predicted by a rigid-viscoplastic FEM analysis. Two kinds of modeling techniques were used to simulate deep drawing process of multilayered sheet. A single-layer FE-model, which combines the three different layers into a macroscopic single layer, predicted well the thickness distribution of the drawn cup. In contrast, the location and the time of fracture were estimated better with a multi-layer FE model, which used different material properties for each of the three layers.

Improvement of Formability of AZ31 Magnesium Alloy Sheet during Warm Deep Drawing (AZ3l 마그네슘합금의 온간디프드로잉시 판재성형성 향상)

  • Rhee, Myeong-Sup;Kang, Dae-Min
    • Transactions of Materials Processing
    • /
    • v.15 no.2 s.83
    • /
    • pp.148-152
    • /
    • 2006
  • In this study, the experiments of warm deep drawing were done with heated die, and with heated die, and blankholder, and cooled punch in order to investigate the formability of AZ31 magnesium alloy sheet in warm deep drawing. For this, warm deep drawing experiments were executed under various temperatures and punch velocities. The results of warm deep drawing with heated die showed that fracture occurred around the punch part at punch velocity of 75mm/min and punch stroke of 10mm under temperature range of 373-523K, but did not occur under temperature range of 548-673K even punch stroke of 25mm. And fracture at the punch stroke of 25mm and the temperature of 523K did not occur under the punch velocity of 30mm/min, but occurred under punch velocity of 75 and 125mm/min. Also warm deep drawing with heated die and blankholder, and cooled punch showed that the temperature range happening maximum height under punch velocity of 10-100mm/min was around 498-523K. Finally, with heating and cooling technique necking of AZ31 magnesium alloy occurred at punch shoulder part under the temperature range of 293-423K, but at die wall part under the temperature range of 473-573K.

Improvement on the Formability of Magnesium Alloy Sheet by Heating and Cooling Method (가열냉각방법에 의한 마그네슘합금의 판재성형성 개선)

  • Kang Dae-Min;Manabe Ken-ich
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.13 no.6
    • /
    • pp.93-98
    • /
    • 2005
  • The purpose of this study is to confirm the improvement of formability of AZ31 magnesium alloy sheet by using local heating and cooling technique. For this, the experiments of warm deep drawing were done under the temperatures of $100^{\circ}C\~400^{\circ}C$, and the punch velocity of 10, 100mm/min. Also FE analysis under the temperatures of blankholder and die of $150^{\circ}C,\;225^{\circ}C\;and\;300^{\circ}C$ for tools(holder and die) was executed with considering heat teansfer. From the results, the formability of AZ31 magnesium alloy, espicially the temperatures of $225^{\circ}C\~250^{\circ}C$ for tools(holder and die)improved remarkably. And the experiments and simulations showed that necking under room temperature for tools occured under the part of punch shoulder while at $300^{\circ}C$ for tools, at the part of die shoulder.