Study on Formability about ME20M Magnesium Alloy Sheet

2010 ◽  
Vol 136 ◽  
pp. 23-27
Author(s):  
Ting Fang Zhang ◽  
Shi Kun Xie

Warm forming of magnesium alloy sheet has attracted more and more attention in recent years. Mechanics tension test has been made in this paper in order to study the constitutive relationship of ME20M magnesium alloy sheet at different temperatures and strain rates. And a constitutive relationship which includes a softening factor has been put forward. Warm deep drawing experiment and numerical simulation on ME20M magnesium alloy sheet have been made in which the attention was focused on the forming temperature. The results showed that the limit deep drawing height of ME20M magnesium alloy sheet can be dramatically improved as the temperature goes up, especially when the temperature was over about 250°C. Simultaneity, it is feasible and effective to add a material model into numerical simulation software by user subroutine.

2011 ◽  
Vol 138-139 ◽  
pp. 754-758
Author(s):  
X.Q. Cao ◽  
J.W. Wang ◽  
Y. Liu ◽  
Cheng Zhong Chi ◽  
L.C. Li ◽  
...  

The effect of forming temperature on the deep drawability (limit drawing ratio (LDR)) of AZ31 magnesium alloy sheet was studied both numerically and experimentally by the use of finite element analysis software DYNAFORM and specially designed warm deep drawing die set. The simulation model was built by SolidWorks 2009, 3-Parameter_Barlat model with BT shell unit was adopted as material model. The constitutive relation of the material was provided by uniaxial isothermal tension tests at different temperatures. After being set, all parameters were referred to famous explicit dynamic solver LS-DYNA. The simulation results showed that the LDR of the AZ31 magnesium alloy sheet is increased with the increase of the temperature initially, but after the temperature reached 423K, the LDR reached the maximum, and then decrease with the increase of temperature in the temperature range studied (room temperature-673K). PTEF was used as lubricant in the experiment. Experimental results showed same trend as numerical simulation results in the studied range of temperature, and LDR reached the maximum of 3.0 at 423K. It is shown that the results of numerical simulation have a good agreement with that of the experiment. By analyzing the microstructure of the drawn-cup walls at different temperatures, it is found that grains were stretched along the direction of tension at temperatures lower than 423K. And there appeared a large number of fine recrystallized grains when forming temperature is 423K showing that dynamic recrystallization occurred during forming process. Dynamic recrystallization conducted completely when forming temperature increased higher than 423K, but the material softening would aggravate with the increase of temperature and on the contrary would do harm to the deep drawing of AZ31 magnesium alloy sheet, resulting the decrease of LDR.


Magnesium ◽  
2005 ◽  
pp. 848-853
Author(s):  
Shi-Hong Zhang ◽  
Kun Zhang ◽  
Zhong-Tang Wang ◽  
Chuan-Fu Yu ◽  
Yi Xu ◽  
...  

2007 ◽  
Vol 340-341 ◽  
pp. 639-644 ◽  
Author(s):  
Ying Hong Peng ◽  
Qun Feng Chang ◽  
Da Yong Li ◽  
Hu Jie ◽  
Xiao Qin Zeng

Blank holder force (BHF) plays an important role in sheet metal forming. Previous studies demonstrated that variable blank holder forces can improve the cold formability of steel blank, but the research on the application of variable blank holder force in warm forming of magnesium sheet forming has not been well investigated. In this study, the mechanical property of AZ31 magnesium alloy sheet is measured through some uniaxial tensile tests. In order to obtain the variational rule of the BHF, a mathematical model of BHF is deduced based on the energy theory. The variational rule of the BHF over the punch stroke is analyzed. Finally, three profiles of the BHF curve are designed, and the numerical simulation of warm deep drawing process of magnesium alloy sheet is also performed. A suitable variable blank holder force scheme is obtained through comparison among three results of simulation. The simulation indicates that the limiting drawing ratio of AZ31 magnesium alloy sheet can be improved from 3.0 to 3.5 with the suitable blank holder force varied by an inverted V curve.


2010 ◽  
Vol 148-149 ◽  
pp. 241-244
Author(s):  
Zhong Tang Wang ◽  
Shi Hong Zhang ◽  
Guang Xia Qi ◽  
Rong Hui Chang

Magnesium alloy tailor-welded blanks(MTWBs) of AZ31 and AZ80 sheet had been manufactured by gas tungsten arc welded(GTAW), which the thickness were 0.8mm. The welding properties of Magnesium alloy sheet had been analyzed, and the technology parameters of GTAW were determined by experiment study, which was that welding thread being Φ2.0mm, welding electricity 50A, welding voltage 9V, welding rate 12—13cm/min. The research results presented that the grain in welded seam was isometric crystal, and the grains were branching crystal in heat-affected zone (HAZ). For MTWBs of AZ31and AZ80 sheet which the thickness was 0.8mm, the forming parameters were that the forming temperature of AZ31 being 190-220°C, and forming temperature of AZ80 being 310°C-350°C, and the temperature of tools is 180°C~200°C.


2005 ◽  
Vol 488-489 ◽  
pp. 461-464 ◽  
Author(s):  
Yong Chao Xu ◽  
Shi Hong Zhang ◽  
H.M. Liu ◽  
Z.T. Wang ◽  
W.T. Zheng ◽  
...  

The extruded sheets were prepared at the temperature between 350ıand 400ı, and the magnesium alloy sheet was manufactured by a new method, cross rolling, in which the rolling direction was changed in each pass. At the time, deep drawing of magnesium alloy sheet was investigated at elevated temperatures. The results show that the sheet has refined-grain by cross-rolling after it was annealed at 250ı, and the formability is significantly improved at lower temperatures, which is superior to the extruded sheet and the one-way rolled sheet. Deep drawing of magnesium alloy was performed successfully, and cylindrical cup of limited drawing ratio (LDR) 2.6 and 35 mm deep rectangular box (65ı50) was achieved at the lower temperature of 170ı. The different types of fracture were analyzed and reasonable parameters were determined.


2011 ◽  
Vol 403-408 ◽  
pp. 4360-4363
Author(s):  
Zu Jian Yu ◽  
Jian Hui Li

Magnesium alloy, differential temperature drawing, mould structure, surface roughness Abstract. To improve the formability of magnesium alloy sheet, the differential temperature drawing process was presented, and the mould structure of differential temperature drawing process for magnesium alloy was well-designed and fabricated by analyzing the friction and the stress distribution of material in drawing process. With the blank heated to 200-235°C at the flange by inserting heating coils and thermocouples in die and binder and the drawn cup cooled by injecting cooling water into die and punch, the differential temperature drawing process of magnesium alloy sheet was performed successfully and the value of surface roughness Ra1.6um was adopted for punch, Ra0.4um was adopted for die and binder. The result shows that by using the designed mould, the deep drawing performance of AZ31B magnesium alloy can be enhanced obviously and the value of LDR can be increased form 2.1 to 3.05.


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