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.

A New Approach of Casting Aluminium Alloy Bar by Applying Low Frequency Electromagnetic Field

2014 ◽  
Vol 794-796 ◽  
pp. 167-171
Author(s):  
Xiang Jie Wang ◽  
Gang Sun ◽  
Li Juan Wang ◽  
Peng Wei Li ◽  
Jian Zhong Cui
Keyword(s):  
Electromagnetic Field ◽  
New Technology ◽  
Low Frequency ◽  
High Strength ◽  
Casting Process ◽  
Lower Surface ◽  
Growth Direction ◽  
Direct Chill ◽  
Cast Aluminum ◽  
Low Efficiency

Aluminum is the richest metallic element in the earth, the ingots cast by DC casting process are usually extruded into aluminum bars. When the final products do not require high strength, this process appears to be low efficiency and high cost. We try to design a new technology to cast aluminum bar by horizontal direct chill (HDC) casting process directly. An electromagnetic field is applied during the horizontal continuous casting of 6061 aluminium bar with a diameter of 30mm. The experimental results show the asymmetry of the sump can be overcome by electromagnetic field. Ingot with good upper and lower surface quality is obtained. The structure of ingot is refined and the angle between growth direction and horizontal direction becomes small with increasing casting speed.

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.

Preparing Large Sized Billet of High Strength Aluminum Alloy with the Application of Low Frequency Electromagnetic Field

2012 ◽  
Vol 472-475 ◽  
pp. 723-726
Author(s):  
Yu Bo Zuo ◽  
Zhi Hao Zhao ◽  
Qing Feng Zhu ◽  
Xiang Jie Wang ◽  
Jian Zhong Cui
Keyword(s):  
Electromagnetic Field ◽  
Aluminum Alloy ◽  
Large Scale ◽  
Low Frequency ◽  
High Strength ◽  
Direct Chill ◽  
Hot Tearing ◽  
Grain Structure ◽  
Grain Refiner ◽  
7050 Aluminum Alloy

Grain refinement is quite important for producing 7050 alloy billet especially in large scale. Low frequency electromagnetic casting (LFEC) process was used to make 7050 aluminum alloy Φ500 mm billets and study the effect of electromagnetic field on the microstructure. The sound Φ500 mm billets of 7050 alloys without any grain refiner can be successfully prepared by the LFEC process. The results show that low frequency electromagnetic field has a significant grain refining effect on 7050 alloy and can effectively eliminate feather grain structure. The microstructures of LFEC ingot from the border to the center of the cross section are all equiaxed grains and are finer and more uniform than that of conventional direct chill (DC) cast billets. The LFEC process also shows a strong power to eliminate hot tearing during casting large sized billet of high strength aluminium alloy.

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.

The Numerical and Experimental Study on Electromagnet-Air Knife DC Casting Process of Large-Size AA 7055 Aluminum Alloys

2014 ◽  
Vol 783-786 ◽  
pp. 319-324
Author(s):  
Hai Tao Zhang ◽  
Jian Zhong Cui ◽  
Hiromi Nagaumi
Keyword(s):  
Electromagnetic Field ◽  
Flow Direction ◽  
Low Frequency ◽  
Casting Process ◽  
Stress And Strain ◽  
Large Size ◽  
Dc Casting ◽  
Physical Fields ◽  
7055 Aluminum Alloy ◽  
Air Knife

In this paper, Low frequency electromagnetic field and air knife are applied simultaneously to produce large-size AA 7055 aluminum alloy ingots during DC casting. Moreover, the effects of low frequency electromagnetic field and air knife on macro-physical fields during DC casting as well as microstructure and crack in the ingots are studied and analyzed by the numerical and experimental methods. Comparison of the calculated results indicates that applying electromagnetic field can modify the flow direction and increase the velocity of melt flow and homogenize the distribution of temperature in the sump, and applying air knife can homogenize the distribution of temperature and decrease the stress and strain in the solidified ingots. Further, the microstructure of the billet is refined remarkably and the crack is eliminated by applying electromagnetic field and air knife during DC casting because of modification of the macro-physical fields

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.

Direct Chill Casting of Φ500mm ZK60 Magnesium Alloy Billets under Low Frequency Electromagnetic Field

2011 ◽  
Vol 686 ◽  
pp. 26-29
Author(s):  
Zhi Qiang Zhang ◽  
Qi Chi Le ◽  
Jian Zhong Cui
Keyword(s):  
Electromagnetic Field ◽  
Magnesium Alloy ◽  
Surface Quality ◽  
Low Frequency ◽  
Direct Chill ◽  
Hot Tearing ◽  
Direct Chill Casting ◽  
Chill Casting ◽  
Zk60 Magnesium Alloy

Effects of low frequency electromagnetic field on surface quality, microstructure and hot-tearing tendency of direct chill casting of Φ500mm ZK60 magnesium alloy billets were investigated. The results show that with the application of the low frequency electromagnetic field, the surface quality of Φ500mm ZK60 magnesium alloy billets has been markedly improved, and the depth of cold fold is decreased. In the conventional direct chill casting, the microstructures of the billet, especially at the center, are coarse. The distribution of the grain size is non-uniform throughout the billet. From the edge to the center, the microstructure gradually changes from fine to coarse in all billets. However, under the low frequency electromagnetic casting, the microstructures of the billet is significantly refined, the distribution of the grains size is relatively uniform from the billets edge to the billets center. And it also shows that the hot-tearing tendency of direct chill casting Φ500mm ZK60 magnesium alloy billets under low frequency electromagnetic field is significantly reduced.

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