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Title: Warm Deep Drawing Of Rectangular Cups With Magnesium Alloy AZ31 Sheets

Abstract

Recently, magnesium alloys have been widely applied in automotive and electronic industries as the lightest weight structural and functional materials. Warm forming of magnesium alloys has attracted much attention due to the very poor formability of Mg alloys at room temperature. The formability of magnesium alloy sheet at elevated temperature is significantly affected by the processing parameters. Among them the forming temperature, the punch speed, the geometrical shape of the blank, the blank holder force and the lubrication are probably the most relevant. In this research, the deep drawing of rectangular cups with AZ31 sheets was conducted at elevated temperatures with different process parameters. The finite element analyses were performed to investigate the effects of the process parameters on the formability of rectangular cup drawing and to predict the process defects during the process. The material yield condition was modeled using the isotropic Von Mises criterion. The flow stress data were obtained from tensile tests.

Authors:
 [1];  [2]; ;  [1];  [3]
  1. Department of Mechanical and Management Engineering (DIMeG), Polytechnic of Bari, 70126 Bari (Italy)
  2. (China)
  3. Institute of Metal Research, Chinese Academy of Sciences, 110016 Shenyang (China)
Publication Date:
OSTI Identifier:
21061729
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 908; Journal Issue: 1; Conference: NUMIFORM 2007: 9. international conference on numerical methods in industrial forming processes, Porto (Portugal), 17-21 Jun 2007; Other Information: DOI: 10.1063/1.2740872; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; COMPUTERIZED SIMULATION; DEFECTS; DRAWING; FINITE ELEMENT METHOD; FLOW STRESS; LUBRICATION; MAGNESIUM ALLOYS; PROCESSING; SHEETS; TEMPERATURE DEPENDENCE; TENSILE PROPERTIES; VELOCITY

Citation Formats

Ren, L. M., Institute of Metal Research, Chinese Academy of Sciences, 110016 Shenyang, Palumbo, G., Tricarico, L., and Zhang, S. H. Warm Deep Drawing Of Rectangular Cups With Magnesium Alloy AZ31 Sheets. United States: N. p., 2007. Web. doi:10.1063/1.2740872.
Ren, L. M., Institute of Metal Research, Chinese Academy of Sciences, 110016 Shenyang, Palumbo, G., Tricarico, L., & Zhang, S. H. Warm Deep Drawing Of Rectangular Cups With Magnesium Alloy AZ31 Sheets. United States. doi:10.1063/1.2740872.
Ren, L. M., Institute of Metal Research, Chinese Academy of Sciences, 110016 Shenyang, Palumbo, G., Tricarico, L., and Zhang, S. H. Thu . "Warm Deep Drawing Of Rectangular Cups With Magnesium Alloy AZ31 Sheets". United States. doi:10.1063/1.2740872.
@article{osti_21061729,
title = {Warm Deep Drawing Of Rectangular Cups With Magnesium Alloy AZ31 Sheets},
author = {Ren, L. M. and Institute of Metal Research, Chinese Academy of Sciences, 110016 Shenyang and Palumbo, G. and Tricarico, L. and Zhang, S. H.},
abstractNote = {Recently, magnesium alloys have been widely applied in automotive and electronic industries as the lightest weight structural and functional materials. Warm forming of magnesium alloys has attracted much attention due to the very poor formability of Mg alloys at room temperature. The formability of magnesium alloy sheet at elevated temperature is significantly affected by the processing parameters. Among them the forming temperature, the punch speed, the geometrical shape of the blank, the blank holder force and the lubrication are probably the most relevant. In this research, the deep drawing of rectangular cups with AZ31 sheets was conducted at elevated temperatures with different process parameters. The finite element analyses were performed to investigate the effects of the process parameters on the formability of rectangular cup drawing and to predict the process defects during the process. The material yield condition was modeled using the isotropic Von Mises criterion. The flow stress data were obtained from tensile tests.},
doi = {10.1063/1.2740872},
journal = {AIP Conference Proceedings},
number = 1,
volume = 908,
place = {United States},
year = {Thu May 17 00:00:00 EDT 2007},
month = {Thu May 17 00:00:00 EDT 2007}
}
  • AZ31 magnesium alloy sheet with good shape and formability is fabricated by warm cross rolling. Uniaxial tensile tests are conducted using a Gleeble 3500 thermal - mechanical simulator, and the mechanical properties of AZ31 magnesium alloy sheet are analyzed. A warm deep drawing process of square part is also simulated by the finite element method. The influences of blank holder force on the formability are numerically investigated. A double-action hydraulic press that can realize adjustable blank holder forces is developed and its working principle and control system are introduced. Some warm deep drawing experiments of square parts of AZ31 magnesiummore » alloy sheet are also performed. Different variation schemes of the blank holder force with the stroke of the punch are tested, and the experiment results are compared. Results show that the suitable blank holder force variation scheme is a ladder curve with the punch stroke. Adopting the variable blank holder force technique can improve 13.2% of the drawing depth of square parts of AZ31 magnesium alloy sheet.« less
  • Magnesium alloys, as one of the lightest metal structural materials, are attracting more and more attention. At present, most of Mg alloy products are manufactured by die casting. For enlarging the applications of Mg alloys, many researchers are engaged in developing its plastic forming technology. However, the study on warm sheet hydroforming of Mg alloy is rarely reported. Therefore, a set of warm sheet hydroforming tools was designed for experimental research on the hydroforming of rectangular Mg alloy cups with a step cavity. The corners of the deeper cavity are difficult to form directly because of the severe stretching. Multi-stagemore » hydroforming method was used to improve the sheet thickness reduction in the corners of the deeper cavity. Several different two-stage hydroforming methods were realized by elastic-plastic finite element simulation. According to the results of finite element simulation, the influence of forming methods on the minimum thickness of formed parts and the reasons were analyzed, and the optimal process for the rectangular Mg alloy cup with a step cavity was determined.« less
  • Hydroforming of magnesium (Mg) alloy sheet metal offers the possibility to form geometrically complex sheet metal parts that are applicable within automotive and electronic industry etc. However, due to the limited formability of Mg alloy at ambient temperature hydroforming of Mg alloy sheet metal has to be conducted at elevated temperature. In the present study an experimental warm hydroforming process using a low melting point alloy as forming medium is presented and on the basis of this a 2D thermo-mechanical finite element model is setup in order to analyze the temperature distribution in the Mg alloy workpiece during forming. Themore » results show that the temperature in the workpiece is nearly uniform and nearly identical to the temperature of the forming medium.« less
  • This paper applies a multi-step inverse approach to predict the forming of AZ31 magnesium alloy sheets. An in-house finite element code named “INAPH”, which implements the inverse approach formulation by Guo et al. (Int. J. Numer. Methods Eng., 30, 1385-1401), has been used for the forming analysis. This inverse approach uses the deformation theory of plasticity and assumes that the deformation is independent of the loading history. Failure during forming is predicted by a stress-based criterion or a forming limit diagram-based criterion. The INAPH predictions have been compared with experimental results of Takuda et al (Journal of Materials Processing Technology,more » 89-90:135-140) and incremental analysis using ABAQUS. The multi-step inverse analysis has been shown to very quickly and fairly accurately predict stress, plastic strain, thickness distributions and failure locations on deeply drawn parts made of AZ31 magnesium alloy. The capability of INAPH to predict the formability of magnesium alloys has also been demonstrated at various temperatures. As magnesium alloys possess very limited formability at room temperature, and their formability becomes better at higher temperatures (> 100oC), the inverse analysis constitutes an efficient and valuable tool to predict forming of magnesium alloy parts as a function of temperature. In addition, other processing and design parameters such as the initial dimensions, final desired shape, blank holder forces, and friction can be quickly adjusted to assess the forming feasibility.« less
  • In the present study, the stamping process for manufacturing cell phone cases with magnesium alloy AZ31 sheets was studied using both the experimental approach and the finite element analysis. In order to determine the proper forming temperature and set up a fracture criterion, tensile tests and forming limit tests were first conducted to obtain the mechanical behaviors of AZ31 sheets at various elevated temperatures. The mechanical properties of Z31 sheets obtained from the experiments were then adopted in the finite element analysis to investigate the effects of the process parameters on the formability of the stamping process of cell phonemore » cases. The finite element simulation results revealed that both the fracture and wrinkle defects could not be eliminated at the same time by adjusting blank-holder force or blank size. A drawbead design was then performed using the finite element simulations to determine the size and the location of drawbead required to suppress the wrinkle defect. An optimum stamping process, including die geometry, forming temperature, and blank dimension, was then determined for manufacturing the cell phone cases. The finite element analysis was validated by the good agreement between the simulation results and the experimental data. It confirms that the cell phone cases can be produced with magnesium alloy AZ31 sheet by the stamping process at elevated temperatures.« less