Experimental and Numerical Study of the Influence of a Low-Frequency Electromagnetic Field on the As-Cast Structure of Horizontal Direct Chill Casting Aluminum Alloy Slab

2009 ◽  
Vol 79-82 ◽  
pp. 1265-1268
Author(s):  
Zhi Hao Zhao ◽  
Jian Zhong Cui ◽  
Qing Feng Zhu ◽  
Gao Song Wang
Keyword(s):  
Electromagnetic Field ◽  
Aluminum Alloy ◽  
Temperature Field ◽  
Flow Pattern ◽  
Low Frequency ◽  
Direct Chill ◽  
Chill Casting ◽  
Cast Structure ◽  
Casting Aluminum Alloy ◽  
Casting Aluminum

The influences of low frequency electromagnetic field on the as-cast structure of horizontal direct chill casting aluminum alloy slab were experimental and numerical studied. The results of numerical analysis show that the interaction of the low-frequency electromagnetic field and the melt can generate an electromagnetically induced forced flow in the melt, which, in turn, changes flow pattern and temperature field in the mold. the as-cast structure of slab can be greatly improved by the changes of flow pattern and temperature field. The results of experimental analysis show that the grains of low frequency electromagnetic casting (LFEC) are fine, uniform, equiaxed, rosette-shaped; the surface of the slab of LFEC has no cold shut and less exudations. Moreover, the low-frequency electromagnetic field can improve the distribution of solute elements in the slab. The macrosegregation such as negative segregation and gravity segregation were reduced, which results in the homogenous distributions of the solute elements over the cross-section of the slab.

Low-Frequency Electromagnetic Field Influencing Horizontal Direct Chill Casting of Aluminum Alloy Rods

2007 ◽  
Vol 546-549 ◽  
pp. 691-696
Author(s):  
Zhi Hao Zhao ◽  
Jian Zhong Cui ◽  
Qing Feng Zhu
Keyword(s):  
Electromagnetic Field ◽  
Aluminum Alloy ◽  
Low Frequency ◽  
Casting Process ◽  
Gravitational Effect ◽  
Direct Chill ◽  
Cooling Condition ◽  
Chill Casting ◽  
Alloy Ingot ◽  
Production Route

The horizontal direct chill (HDC) casting process is a well-established production route for an aluminum alloy ingot; however, the ingot may suffer from inhomogeneous microstructures and serious macrosegregation due to the unbalanced cooling condition and gravitational effect. In order to control the defect, a low frequency electromagnetic field has been applied in the HDC casting process and its influences on microstructures and macrosegregation have been studied. The results show that the low frequency electromagnetic field can improve macrostructures, reduce inhomogeneous microstructures and macrosegregation in HDC product; and two main parameters of the electromagnetic field—density and frequency influence the microstructures and solution distribution along the diameter of the ingot significantly. In the range of ampere-turns and frequency employed in the experiments, the optimum ampere-turns and frequency have been found to be 10000At, 30Hz.

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.

Effect of Electromagnetic Field on Horizontal Direct Chill Casting of 7075 Aluminum Alloy

2010 ◽  
Vol 654-656 ◽  
pp. 982-985 ◽  
Author(s):  
Qing Feng Zhu ◽  
Zhi Hao Zhao ◽  
Xiang Jie Wang ◽  
Jian Zhong Cui
Keyword(s):  
Electromagnetic Field ◽  
Aluminum Alloy ◽  
Electromagnetic Fields ◽  
Molten Pool ◽  
Casting Process ◽  
Direct Chill ◽  
7075 Aluminum Alloy ◽  
Solidification Behavior ◽  
Cast Structure ◽  
Thermal Distribution

The influence of different electromagnetic fields on the horizontal direct chill (HDC) casting of aluminum alloy is studied. 7075 aluminum alloy with 100-mm in diameter is produced by HDC casting process; single electromagnetic field located before or around the mold and an out-phase electromagnetic field (OPEMF) are applied in the HDC casting process. The effect of different electromagnetic fields on the HDC casting solidification behavior and as-cast structure is investigated. The electromagnetic field can effectively make uniform thermal distribution in the molten pool and refine the as-cast structure. The OPEMF is more efficient than the single electromagnetic field in improving the as-cast structure of HDC cast ingots.

Homogenization Behaviors of Low Frequency Electromagnetic Casting and Direct Chill Casting 7050 Aluminum Alloy

2010 ◽  
Vol 97-101 ◽  
pp. 991-994
Author(s):  
Zhi Hao Zhao ◽  
Jian Zhong Cui ◽  
Jing Wang ◽  
Gao Song Wang
Keyword(s):  
Aluminum Alloy ◽  
Low Frequency ◽  
Eutectic Structure ◽  
Optical Microscope ◽  
Direct Chill ◽  
Direct Chill Casting ◽  
Chill Casting ◽  
Electromagnetic Casting ◽  
7050 Aluminum Alloy ◽  
Dsc Analyses

7050 aluminum alloy ingots were produced by low frequency electromagnetic casting (LFEC) and direct chill casting (DC) respectively. As-cast microstructures and homogenization behaviors of LFEC and DC ingots were investigated experimentally. The optical microscope and DSC analyses shown that the grain size of LFEC ingot was finer and the content of constituents and eutectic structure was less than that of DC ingot. Accordingly, the homogenization behaviors of the LFEC and DC ingots were significantly different. The remnant constituents of LFEC ingot were less in content and smaller in size than that of DC ingot after homogenization at 480°C for various lengths of time. Similar to the dissolving of constituents, the LFEC ingot exhibited faster diffusion kinetics of alloying elements from grain boundary to inner. The concentrations of Cu, Mg and Zn inside grain of LFEC ingot after homogenization for 12 h were 2.4%, 2.2% and 6.5% respectively, but the DC ingots had not reach the level even for 48 h.

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