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 Low Frequency Electromagnetic Field on Segregation Layer during Hot-Top Casting of Aluminium Alloy

2011 ◽  
Vol 189-193 ◽  
pp. 3795-3798
Author(s):  
Xiang Jie Wang ◽  
Jian Zhong Cui ◽  
Hai Tao Zhang ◽  
Hui Xue Jiang ◽  
Gao Song Wang
Keyword(s):  
Electromagnetic Field ◽  
Aluminium Alloy ◽  
Surface Segregation ◽  
Low Frequency ◽  
Casting Process ◽  
Direct Chill ◽  
Direct Chill Casting ◽  
Chill Casting ◽  
Direct Chill Casting Process

Surface segregation layer are frequently encountered during aluminium alloy direct chill casting process, and the removal of the surface segregation layer before further processing of the ingot decreases the ingot yield. In this work, the low frequency electromagnetic field was applied to study the effects of low frequency electromagnetic field on segregation layer during the direct chill casting process. The results show that under the effect of the low frequency electromagnetic field, the surface quality of ingot is improved, the structure of the ingot is refined, and the thickness of segregation layer is decreased.

scholarly journals Transient Modeling of Grain Structure and Macrosegregation during Direct Chill Casting of Al-Cu Alloy

Processes ◽  
2019 ◽  
Vol 7 (6) ◽  
pp. 333 ◽  
Author(s):  
Qipeng Chen ◽  
Hongxiang Li ◽  
Houfa Shen
Keyword(s):  
Direct Chill ◽  
Grain Structure ◽  
Fe Model ◽  
Grain Refiner ◽  
Negative Segregation ◽  
Cu Alloy ◽  
Transient Modeling ◽  
Dc Casting ◽  
Columnar Grain

Grain structure and macrosegregation are two important aspects to assess the quality of direct chill (DC) cast billets, and the phenomena responsible for their formation are strongly interacted. Transient modeling of grain structure and macrosegregation during DC casting is achieved with a cellular automaton (CA)–finite element (FE) model, by which the macroscopic transport is coupled with microscopic relations for grain growth. In the CAFE model, a two-dimensional (2D) axisymmetric description is used for cylindrical geometry, and a Lagrangian representation is employed for both FE and CA calculations. This model is applied to the DC casting of two industrial scale Al-6.0 wt % Cu round billets with and without grain refiner. The grain structure and macrosegregation under thermal and solutal convection are studied. It is shown that the grain structure is fully equiaxed in the grain-refined billet, while a fine columnar grain region and a coarse columnar grain region are formed in the non-grain-refined billet. With the increasing casting speed, grains become finer and grow in a direction more perpendicular to the axis, and the positive segregation near the centerline becomes more pronounced. The increasing casting temperature makes grains coarser and the negative segregation near the surface more pronounced.

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.

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.

Simulation of Low Frequency Electromagnetic DC Casting

2014 ◽  
Vol 790-791 ◽  
pp. 390-395 ◽  
Author(s):  
Nejc Kosnik ◽  
Robert Vertnik ◽  
Božidar Šarler
Keyword(s):  
Solid Phase ◽  
Low Frequency ◽  
Casting Process ◽  
Direct Chill ◽  
Temperature Fields ◽  
Step Method ◽  
Fractional Step Method ◽  
Hot Top ◽  
Induction Equation ◽  
Dc Casting

A comprehensive multiphysics model has been developed to describe the effect of the low frequency electromagnetic field (LFEM) [1, on solidification in the hot-top Direct-Chill (DC) casting [ of round aluminium alloy billets. The volume averaged equations and the rigid solid phase assumption are assumed for fluid flow and heat transfer [. The electromagnetic induction equation for the field imposed by the coil is solved using the diffuse approximate method (DAM), structured in axial symmetry with Gaussian weight function, 6 polynomial basis and 9 nodded domains. The heat, mass, and momentum transfer equations are solved in primitive variables by meshless [ method using 5 nodded domains of influence and 5 scaled multiquadrics radial basis functions, using collocation. Explicit time stepping is used. Pressure-velocity coupling is performed by the fractional step method. The effects of intensity and frequency of the LFEM [ on the velocity and temperature fields is investigated. A comparison of the calculated results with different LFEM field process variables with that of the conventional hot-top DC casting process indicates that the velocity patterns, the temperature profiles, and the shape of the sump could be modified remarkably.

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.

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.

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

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.

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