Experimental Investigation of Microsegregation in Low Frequency Electromagnetic Casting of Al-4.5%Cu Binary Alloy

2010 ◽  
Vol 152-153 ◽  
pp. 1217-1221
Author(s):  
Dan Dan Chen ◽  
Hai Tao Zhang ◽  
Xiang Jie Wang ◽  
Jian Zhong Cui
Keyword(s):  
Experimental Investigation ◽  
Electromagnetic Field ◽  
Binary Alloy ◽  
Low Frequency ◽  
Direct Chill ◽  
Solute Content ◽  
Electromagnetic Casting ◽  
Dc Casting

Al-4.5%Cu ingots were prepared by a process of low frequency electromagnetic casting (LFEC) and conventional direct chill (DC) casting, respectively. The effects of low frequency electromagnetic field on the microsegregation were investigated from eutectic analysis and electro probe microanalysis (EPMA). It was found that the amount of the nonequilibrium eutectic and the dimension of the nonequilibrium eutectic were decreasing markedly. In contrast, the solute content in the α-Al phase increased to a certain extent in the presence of the low frequency electromagnetic field, and it increased with the incerasing electromagnetic.

DC Casting of Large Sized Ingot of a High Strength 7xxx Alloy under the Influence of Electromagnetic Field

2013 ◽  
Vol 765 ◽  
pp. 165-169 ◽  
Author(s):  
Jian Zhong Cui ◽  
Hai Tao Zhang ◽  
Yu Bo Zuo
Keyword(s):  
Electromagnetic Field ◽  
Flow Direction ◽  
New Technology ◽  
Low Frequency ◽  
High Strength ◽  
Direct Chill ◽  
Hot Tearing ◽  
Electromagnetic Casting ◽  
Dc Casting ◽  
7Xxx Alloy

Hot tearing and cold cracks are major defects during direct chill (DC) casting of large sized ingots of high strength aluminium alloys. In order to solve these problems, based on a low frequency electromagnetic casting (LFEC) process, a new technology, electromagnetic casting with the application of an air blade (EMA) was developed. In the present work, this new technology was used to prepare large sized AA7055 aluminium alloy ingots and the effects of the low frequency electromagnetic field and the air blade on macro-physical fields, microstructure and cracking are studied by numerical and experimental methods. The results show that applying an electromagnetic field can modify the flow direction, increase the velocity of melt flow and homogenize the distribution of temperature in the sump. Applying an air blade can homogenize the distribution of temperature and decrease the stress and strain in the solidified ingot. Furthermore, the microstructure of the ingot is refined remarkably and cracking is eliminated by simultaneously applying the electromagnetic field and the air blade during DC casting.

Effect of DC Casting Processes on Microstructure of AlCu4.5Mn0.8 Alloy

2013 ◽  
Vol 652-654 ◽  
pp. 2409-2412
Author(s):  
Li Zhou ◽  
Gen Xiang Luo
Keyword(s):  
Electromagnetic Field ◽  
Low Frequency ◽  
Direct Chill ◽  
Direct Chill Casting ◽  
Chill Casting ◽  
Dc Casting ◽  
Semi Solid

The semi-solid billets of AlCu4.5Mn0.8 alloy were cast respectively by low frequency electromagnetic, low-superheated, and conventional direct chill casting. The effect of casting processes on microstructures was investigated. The results show that due to the effect of the low frequency electromagnetic field, the coarse dentritic microstructure is gradually broken up and turned into the homogeneous, fine rosette-shaped non-dentritic microstructures with the increase of electromagnetic frequency from 10 Hz to 30 Hz. When electromagnetic frequency is 30 Hz, the homogeneous, fine non-dentritic microstructure what is suitable for semi-solid reheating and thixo-forming could be obtained successfully.

Coupled Modeling of Electromagnetic Field, Fluid Flow, Heat Transfer and Solidification during Conventional DC Casting and Low Frequency Electromagnetic Casting of 7XXX Aluminum Alloys

2006 ◽  
Vol 15-17 ◽  
pp. 18-23 ◽  
Author(s):  
Hai Tao Zhang ◽  
Hiromi Nagaum ◽  
Yu Bo Zuo ◽  
Jian Zhong Cui
Keyword(s):  
Heat Transfer ◽  
Electromagnetic Field ◽  
Fluid Flow ◽  
Low Frequency ◽  
Casting Process ◽  
Coupled Modeling ◽  
Electromagnetic Casting ◽  
Flow Heat ◽  
Dc Casting ◽  
Heat Transfer And Solidification

A comprehensive mathematical model has been developed to describe the interaction of the multiple physics fields during the conventional DC casting and LFEC (low frequency electromagnetic casting) process. The model is based on a combination of the commercial finite element package ANSYS and the commercial finite volume package FLUENT, with the former for the calculation of the electromagnetic field and the latter for the calculation of the magnetic driven fluid flow, heat transfer and solidification. Moreover, the model has been verified against the temperature measurements obtained from two 7XXX aluminum alloy billets of 200mm diameter, cast during the conventional DC casting and the LFEC casting processes. In addition, a measurement of the sump shape of the billets were carried out by using addition melting metal of Al-30%Cu alloy into the billets during casting process. There was a good agreement between the calculated results and the measured results. Further, comparison of the calculated results during the LFEC process with that during the conventional DC casting process indicated that velocity patterns, temperature profiles and the sump depth are strongly modified by the application of a low frequency electromagnetic field during the DC casting.

Effect of Physical Fields on Solidification Structures of DC Casting AZ80 Magnesium Alloy Billets

2011 ◽  
Vol 105-107 ◽  
pp. 1616-1619
Author(s):  
Zhi Qiang Zhang ◽  
Qi Chi Le ◽  
Jian Zhong Cui
Keyword(s):  
Magnesium Alloy ◽  
Continuous Casting ◽  
Low Frequency ◽  
Direct Chill ◽  
Ultrasonic Fields ◽  
Electromagnetic Casting ◽  
Az80 Magnesium Alloy ◽  
Continuously Cast ◽  
Dc Casting ◽  
Physical Fields

AZ80 magnesium alloy was semi-continuously cast under different physical fields which were conventional direct chill (DC) casting, low frequency electromagnetic casting (LFEC), ultrasonic casting (USC) and electromagnetic-ultrasonic combined casting (ECUC), respectively. The effect of different physical fields on solidification structures of AZ80 alloys was investigated. The results show that compared with the conventional DC casting, structures of AZ80 alloys billets cast with LFEC and USC have been greatly refined. The effective refinement takes place in the edge of billets when LFEC is applied. However, the effective refinement takes place in the center of billets when USC is applied. When combination of low frequency electromagnetic and ultrasonic fields is applied during semi-continuous casting AZ80 magnesium alloy billet, structures of AZ80 alloys are refined significantly in the whole billets everywhere and more uniform.

Effect of Electromagnetic Field on the Macrosegregation Behaviour of Al-Cu Alloy Ingot Prepared with Direct-Chill Casting Process

2016 ◽  
Vol 877 ◽  
pp. 84-89
Author(s):  
Yu Bo Zuo ◽  
Qing Feng Zhu ◽  
Lei Li ◽  
Guang Ming Xu ◽  
Jian Zhong Cui
Keyword(s):  
Electromagnetic Field ◽  
Low Frequency ◽  
Casting Process ◽  
Direct Chill ◽  
Grain Refiner ◽  
Negative Segregation ◽  
Cu Alloy ◽  
Dc Casting ◽  
Positive Segregation ◽  
Direct Chill Casting Process

A low frequency electromagnetic field was introduced into the direct chill (DC) casting process and the ingots of Al-Cu alloy were prepared to study the macrosegregation behaviour of the ingots under the influence of the electromagnetic field. The experimental results showed that there is an obvious positive segregation near to the surface and a negative segregation in the centre area of the ingot. Cu shows the highest segregation tendency among the main elements of Cu, Mg and Mn. Grain refiner element Ti shows a segregation trend opposite to that of Cu. With the application of electromagnetic field, the negative centreline segregation in the centre area of the ingot was evidently reduced although it didn’t show significant effect on the segregation near to the ingot surface. A significant grain refinement was also achieved with the application of electromagnetic field. The mechanism of the reduction of macrosegregation with electromagnetic field was also analyzed in the present work.

Effects of the Low Frequency Electromagnetic Field on the Centerline Macrosegregation of 7075 Aluminum Ingots

2011 ◽  
Vol 295-297 ◽  
pp. 1705-1708
Author(s):  
Dan Dan Chen ◽  
Hai Tao Zhang ◽  
Xiang Jie Wang ◽  
Jian Zhong Cui
Keyword(s):  
Electromagnetic Field ◽  
Steady State ◽  
Mushy Zone ◽  
Transition Region ◽  
Low Frequency ◽  
Casting Process ◽  
Direct Chill ◽  
Mushy Region ◽  
Chill Casting ◽  
Temperature Contour

The effects of the low frequency electromagnetic field on the macrosegregation of the 7075 aluminum ingots were investigated. The 7075 aluminum ingots with the diameter of 200 mm were prepared by the conventional direct chill casting and the low frequency electromagnetic field casting (LFEC) processes, respectively. The temperature during casting at steady state was measured, and the mushy region was observed from the temperature contour. The concentrations of the alloying elements were measured by the spectrograph. It was found that the transition region was broadened, but the mushy zone became narrower with presence of the low frequency electromagnetic field. The centerline macrosegregation of the ingots was alleviated by the low frequency electromagnetic casting process.

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