Effects of Low Frequency Electromagnetic Field on Hot Tear during Hot-Top Casting Process

2010 ◽  
Vol 97-101 ◽  
pp. 1012-1015
Author(s):  
Xiang Jie Wang ◽  
Jian Zhong Cui ◽  
Qing Feng Zhu ◽  
Zhi Hao Zhao
Keyword(s):  
Electromagnetic Field ◽  
Flow Direction ◽  
Low Frequency ◽  
Casting Process ◽  
Hot Top ◽  
Aluminium Casting

Hot tear is one of the main defects during the aluminium casting process, and it usually occurs during solidification. In this work, the low frequency electromagnetic field was applied to study the effects of low frequency electromagnetic field on hot tear during the conventional hot-top casting process. The results show that under the effect of the low frequency electromagnetic field, the structure of the ingot is refined, the flow direction is changed, and the depth of the sump becomes shallow. All these factors can decrease the hot tear susceptibility.

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

Effects of Low Frequency Electromagnetic Field on the Solidification Structure of 6063 Aluminum Alloy during Hot-Top Casting

2011 ◽  
Vol 675-677 ◽  
pp. 857-860
Author(s):  
Xiang Jie Wang ◽  
Jian Zhong Cui ◽  
Qing Feng Zhu
Keyword(s):  
Electromagnetic Field ◽  
Aluminum Alloy ◽  
Low Frequency ◽  
Casting Process ◽  
Liquid Pool ◽  
Solidification Structure ◽  
Cooling Curves ◽  
Melt Temperature ◽  
Hot Top ◽  
6063 Aluminum Alloy

Low frequency electromagnetic (LFE) field was applied during the conventional hot-top casting process. Thermocouples were used to measure the cooling curves from the border to the center of the ingot during steady-state of casting process, cooling curves were obtained, and effects of low frequency electromagnetic field on the solidification, macrostructure during the conventional hot-top casting for 6063 aluminum alloy process were analyzed. The experimental results show that the forced convection caused by the low frequency electromagnetic (LFE) filed can make the melt temperature uniform, promote the evacuation of superheat, make the temperature in the liquid pool lower than the liquidus temperature of 6063 aluminum alloy, increase the number of floating nuclei, make the ingot with fine and homogeneous macrostructure, though there is no addition of any grain refiners.

A Numerical Simulation of the Electromagnetic Hot-Top Casting of 6063 Aluminum Alloy

2010 ◽  
Vol 148-149 ◽  
pp. 1680-1683
Author(s):  
Xiang Jie Wang ◽  
Jian Zhong Cui ◽  
Hai Tao Zhang
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Electromagnetic Field ◽  
Low Frequency ◽  
Casting Process ◽  
Two Dimensional ◽  
Electromagnetic Process ◽  
Hot Top ◽  
6063 Aluminum Alloy ◽  
Good Agreement

On the basis of conventional hot-top casting and Casting, Refining and Electromagnetic process, a lower frequency electromagnetic field was applied during the hot-top casting process. A comprehensive two-dimensional (2-D) mathematical model based upon the ANSYS and FLUENT has been developed for the computation of the electromagnetic field, solidification, fluid flow and heat transport during conventional and low frequency electromagnetic hot-top casting processes. The results show that there is a good agreement between the experimental results and calculated results.

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.

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.

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.

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.

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