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EFFECT OF LOW-FREQUENCY ELECTROMAGNETIC FIELD ON THE AS-CASTING MICROSTRUCTURES AND MECHANICAL PROPERTIES OF HDC 2024 ALUMINUM ALLOY 被引量:4
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作者 Q.F. Zhu Z.H. Zhao J.Z. Cui Y.B. Zuo F. Qu 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2008年第3期205-210,共6页
The influences of the low frequency electromagnetic field on the horizontal direct chill casting process were investigated experimentally. Ingots of 2024 aluminum alloy with a cross size of 40 mm× 200 mm were pro... The influences of the low frequency electromagnetic field on the horizontal direct chill casting process were investigated experimentally. Ingots of 2024 aluminum alloy with a cross size of 40 mm× 200 mm were produced by the conventional horizontal chill casting process and low frequency electromagnetic horizontal chill casting processre- spectively. The as-cast structures and the mechanical property of the ingots were examined. The results showed that the low frequency electromagnetic field could sub- stantially refine the microstructures and pronouncedly reduce the macrosegregation in the horizontal direct chill casting process. Moreover, the surface quality of the ingot was prominently improved by the low frequency electromagnetic field. The fracture strength and elongation percentage of the ingot was increased with the low frequency electromagnetic field. 展开更多
关键词 Horizontal direct chill casting Low frequency electromagnetic field 2024 aluminum alloy MICROSTRUCTURES MACROSEGREGATION
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Effect of Low Frequency Electromagnetic Field on Macrosegregation of Horizontal Direct Chill Casting Aluminum Alloys
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作者 Zhihao ZHAO, Jianzhong GUI, Jie DONG and Beijiang ZHANGThe Key Laboratory of Electromagnetic Processing of Materials, Ministry of Education, P.O. Box 314, Northeastern University, Shenyang 110004, ChinaPh.D. candidate, 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2005年第1期75-78,共4页
The horizontal direct chill (HDC) casting process is a well-established production route for aluminum alloy ingot but the ingot may suffer from macrosegregation sometimes. In order to control the defect, a low frequen... The horizontal direct chill (HDC) casting process is a well-established production route for aluminum alloy ingot but the ingot may suffer from macrosegregation sometimes. In order to control the defect, a low frequency electromagnetic field has been applied in HDC casting process and the relevant influence has been studied. The results show that application of low frequency electromagnetic field can reduce macrosegregation in HDC casting process; and two main parameters of electromagnetic field density and frequency, have great influences on the solution distribution along the diameter of ingot. Moreover, the mechanisms of reduction of macrosegregation by electromagnetic field have been discussed. 展开更多
关键词 Low frequency electromagnetic field Horizontal direct chill casting MACROSEGREGATION Aluminum alloy
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Effect of Middle-frequency Electromagnetic Field on the Semi-continuous Casting for ZK60 Billets
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作者 任政 张兴国 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2010年第3期449-453,共5页
The semi-continuous casting of ZK60 magnesium alloy under different middle frequency electromagnetic field conditions was examined.Effects of middle frequency electromagnetic field on microstructure,precipitations and... The semi-continuous casting of ZK60 magnesium alloy under different middle frequency electromagnetic field conditions was examined.Effects of middle frequency electromagnetic field on microstructure,precipitations and tensile properties are investigated.The results show that the microstructures of ZK60 magnesium alloy are refined and distribution uniformity of precipitations is observed after applying the middle frequency electromagnetic field.And the tensile properties of the billets produced by middle frequency electromagnetic field are increased. 展开更多
关键词 middle frequency electromagnetic field semi-continuous casting ZK60
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Analysis and Simulation of the Influence of Electromagnetic Fields on Living Beings near HV Power Lines Using the FDTD Method
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作者 Anthony Bassesuka Sandoka Nzao 《Open Journal of Applied Sciences》 2023年第12期2343-2359,共17页
Recent decades have seen rapid advances in the field of electrical engineering, such that our environment has become a sea of electrical and magnetic signals, raising questions about the possible effects of low-freque... Recent decades have seen rapid advances in the field of electrical engineering, such that our environment has become a sea of electrical and magnetic signals, raising questions about the possible effects of low-frequency electromagnetic fields on the environment and which are capable of modifying and destroying our ecosystem. Particular interest was given in this article due to a massive influx of population living near high voltage lines. The analysis and simulation of the influence of low frequency electromagnetic fields on living beings in the vicinity of high voltage sources 132 kV and 220 kV in urban areas in DR Congo is the subject of our research with a view to estimating the level of exposure of humans to low frequency electromagnetic fields. To carry out our research, we used the classic method of analyzing the field produced near a high voltage line based on Maxwell’s image theory, the Maxwell-Gauss theorem and Maxwell-Ampère theorem to model and quantify low-frequency electromagnetic fields in the vicinity of high-voltage lines. The 2D FDTD numerical formulation was developed from telegraphers’ equations and allowed us to obtain models of current and voltage induced by electromagnetic fields on living beings below and near HV lines. The different simulations carried out on the proposed models illustrate the effects of the electrical and geometric parameters of the pylons on the distribution of the electromagnetic field in the vicinity of the HV lines. The results obtained were compared to the safety limits recommended by the standards. 展开更多
关键词 Low frequency electromagnetic field Modeling field and Health Maxwell’s Equations FDTD Method electromagnetic Compatibility High Voltage Line
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Study on As-Cast Structure of DC Casting Aluminum Alloy Under Dual Frequency Electromagnetic Field
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作者 ZHAO Zhi-hao WANG Gao-song CUI Jian-zhong 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2012年第S1期265-268,共4页
The as-cast structures of semi-continuous casting aluminum alloy under dual-frequency electromagnetic field were experimental investigated.The results showed that the electromagnetic fields with different frequency ha... The as-cast structures of semi-continuous casting aluminum alloy under dual-frequency electromagnetic field were experimental investigated.The results showed that the electromagnetic fields with different frequency have different function for improving the cast structure of aluminum alloy casting.Imposing medium frequency electromagnetic field can change the surface morphology of melt pool in the casting process,increase the height of melt meniscus,improve the ingot's surface quality,and reduce the thickness of surface segregation.The low frequency electromagnetic field is most obvious to as-cast structure improvement effect because of its high permeability in conductance material.Imposing low-frequency electromagnetic field can change flow pattern and temperature field in the melt,strengthen the heat transfer and mass transfer in the melt,decrease the depth of the sttmp and reduce the temperature gradient.Thus,the as-cast structures are greatly refined,which can lead to the fine equiaxed as-cast structures throughout the cross-section of the ingot. 展开更多
关键词 dual frequency electromagnetic field semi-continuous casting aluminum alloy as-cast structure
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Effects of Different Electromagnetic Fields on Circadian Rhythms of Some Haematochemical Parameters in Rats
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作者 LAURA CONTALBRIGO CALOGERO STELLETTA +4 位作者 LAURA FALCIONI STEFANIA CASELLA GIUSEPPE PICCIONE MORANDO SOFFRITTI AND MASSIMO MORGANTE 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2009年第4期348-353,共6页
Objective To investigate the effects of different electromagnetic fields on some haematochemical parameters of circadian rhythms in Sprague-Dawley rats. Methods The study was carried out in 18 male and 18 female rats ... Objective To investigate the effects of different electromagnetic fields on some haematochemical parameters of circadian rhythms in Sprague-Dawley rats. Methods The study was carried out in 18 male and 18 female rats in good health conditions exposed to 50 Hz magnetic sinusoid fields at the intensity of 1000 μT, 100 μT, and 0 μT (control group) respectively, and in 18 male and 18 female rats in good health conditions exposed to 1.8 GHz electromagnetic fields at the intensity of 50 V/m, 25 V/m and 0 V/m (control group), respectively. Following haematochemical parameters for glucose, triglycerides, and total cholesterol were measured. Results Different effects of electromagnetic fields on circadian rhythms of both male and female rats were observed. Different changes occurred in some haematochemical parameters for glucose, triglycerides, and total cholesterol (P〈0.05). Conclusion Exposure to different electromagnetic fields is responsible for the variations of some haematochemical parameters in rats. 展开更多
关键词 Extremely low frequency electromagnetic fields (50 Hz) Radiofrequency electromagnetic fields (1.8 GHz) Haematochemical parameters Circadian rhythm Sprague-Dawley rat
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Efects of low frequency electromagnetic ield on surface quality, microstructure and hot-tearing tendency of semi-continuous casting ZK60 magnesium alloy billets 被引量:3
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作者 Zhang Zhiqiang Le Qichi +1 位作者 Bao Lei Cui Jianzhong 《China Foundry》 SCIE CAS 2013年第6期351-354,共4页
The low frequency electromagnetic field was applied during direct chill(DC) semi-continuous casting of the ZK60 magnesium alloy billets. Effects of low frequency electromagnetic field on surface quality, microstructur... The low frequency electromagnetic field was applied during direct chill(DC) semi-continuous casting of the ZK60 magnesium alloy billets. Effects of low frequency electromagnetic field on surface quality, microstructure and hot-tearing tendency of Φ500 mm ZK60 magnesium alloy billets were investigated. The results showed that with the application of the low frequency electromagnetic field, the surface quality of the ZK60 magnesium alloy billets is markedly improved and the depth of cold fold is decreased. The microstructure of the billets is also significantly refined. Besides, the distribution of the grain size is relatively uniform from the billet surface towards its center, where the average grain size is 42 μm at surface and 50 μm at center. It also shows that the hot-tearing tendency of DC semi-continuous casting ZK60 magnesium alloy billets is significantly reduced under low frequency electromagnetic field. 展开更多
关键词 ZK60 magnesium alloy billets direct chill casting low frequency electromagnetic field REFINEMENT
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Direct-chilling casting of Mg alloy under electromagnetic and ultrasonic combined field 被引量:2
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作者 崔建忠 张志强 乐启炽 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第B07期297-305,共9页
The effects of low frequency electromagnetic (LFEC) field and ultrasonic (US) field on the microstructures, macrosegregation of alloying elements and the mechanical properties of DC cast AZ80 alloy were studied. The r... The effects of low frequency electromagnetic (LFEC) field and ultrasonic (US) field on the microstructures, macrosegregation of alloying elements and the mechanical properties of DC cast AZ80 alloy were studied. The results show that both LFEC and US fields can refine the grains of the billets, which results in the increase in mechanical properties and uniformity of alloying element distribution. The effective refinement takes place on the edge of ingots when LFEC field is applied, while in the center of billets when field US is adopted. Combined the characteristics of LFEC and US fields, a new process for direct-chilling (DC) casting of Mg-electromagnetic-ultrasonic (ECUS) casting is developed, by which the grains are refined significantly and are more uniform in the whole ingots, and the mechanical properties of the ingots are improved. 展开更多
关键词 low frequency electromagnetic field ultrasonic field Mg alloy DC casting
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DISCHARGE CHANNEL GROWTH IN MICRO EDM OF HIGH FREQUENCY PULSE 被引量:2
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作者 刘宇 王津 +1 位作者 王元刚 赵福令 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2011年第4期353-361,共9页
The influences of intense magnetic pinch effect caused by electromagnetic field with high frequency on discharge channel expansion and plasma configuration change are discussed. The change of Lorentz force exerting on... The influences of intense magnetic pinch effect caused by electromagnetic field with high frequency on discharge channel expansion and plasma configuration change are discussed. The change of Lorentz force exerting on charged particles in discharge channel is calculated under the electromagnetic field with high frequency. Through the theoretical analysis and experimental study, the forming process of discharge channel is conjectured. And it is considered that the changes of discharge channel, such as the decrease of diameter and increase of energy density, coming from the intense magnetic pinch effect in high frequency electromagnetic field, are the main reasons for a series of special phenomena on the machined surface in micro EDM. 展开更多
关键词 micro EDM discharge channel high frequency electromagnetic field magnetic pinch effect discharge crater
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DC casting of light alloys under magnetic fields 被引量:2
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作者 崔建忠 张志强 乐启炽 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第11期2046-2050,共5页
The working principle of LFEC(Low frequency electromagnetic casting) process developed in Northeastern University, China was introduced and the metallurgical results of LFEC were discussed according to the casting p... The working principle of LFEC(Low frequency electromagnetic casting) process developed in Northeastern University, China was introduced and the metallurgical results of LFEC were discussed according to the casting practices. The low frequency field around the mold produces Lorenz force, which can be divided into two parts: one is the potential force which will be balanced by a pressure gradient of the liquid and results in the formation of a convex surface meniscus and improves the surface quality; the other is the rotary force which stirs the liquid in the mold to refine the microstructures and homogenize the distribution of alloying elements. LFEC can refine microstructures remarkably, improve surface quality of the ingots, depress macrosegregation and eliminate cracks. Some new technologies, such as horizontal direct chill casting under low-frequency electromagnetic field (HLEC), DC casting of hollow billets under electromagnetic fields (HBEC), electromagnetic modifying of hypereutectic A1-Si alloys(EMM), air film casting under static magnetic field (AFCM), and multi-ingots casting under low-frequency magnetic field (MLFEC) were developed based on LFEC. 展开更多
关键词 low frequency electromagnetic field light alloy DC casting grain refinement
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Microstructures and constituents of super-high strength aluminum alloy ingots made through LFEC process 被引量:1
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作者 WANG Shuang ZUO Yu-bo CUI Jian-zhong 《China Foundry》 SCIE CAS 2007年第4期280-283,共4页
Ingots of a new super-high strength Al-Zn-Mg-Cu-Zr alloy were produced respectively by low frequency electromagnetic casting(LFEC)and by conventional direct chill(DC)casting process.Microstructure and constituents of ... Ingots of a new super-high strength Al-Zn-Mg-Cu-Zr alloy were produced respectively by low frequency electromagnetic casting(LFEC)and by conventional direct chill(DC)casting process.Microstructure and constituents of the ingots were studied.The results indicated that the LFEC process significantly refines microstructure and constituents of the alloy,and to some extent,decreases the area(or volume)fraction of constituents and eutectic structure precipitated at grain boundaries.But,no difference in the type of constituents was observed between LFEC and DC ingots.The results also showed LFEC process can improve the as-cast mechanical properties. 展开更多
关键词 Al-Zn-Mg-Cu-Zr alloy low frequency electromagnetic field DC casting MICROSTRUCTURE CONSTITUENT
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Effect of Induction Heat on Initial Solidification During Electromagnetic Continuous Casting of Steel 被引量:4
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作者 WANG Hong-ming LI Gui-rong 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2010年第7期13-18,共6页
A three-dimensional finite element model of electromagnetic field and temperature field was developed to investigate the effects of induction heat of high frequency electromagnetic field on the early solidification pr... A three-dimensional finite element model of electromagnetic field and temperature field was developed to investigate the effects of induction heat of high frequency electromagnetic field on the early solidification process of molten steel.The results show that the increases of exciting current frequency make the effects of induction heat on solidification increase remarkably.Contrarily,the effects of induction heat on solidification process are weakened sharply with the increase of casting speed.Especially,when the casting speed exceeds a certain value,the effects of induction heat on solidification process are nearly negligible. 展开更多
关键词 high frequency electromagnetic field induction heat initial solidification
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