Electromagnetic Induction Heating Research Articles

Bonding horizontal aligned carbon nanotubes with a high-frequency electromagnetic induction heating method

This paper introduces an innovative method using high-frequency electromagnetic induction heating to realize a partial heating process without increasing overall chip temperature. This method provides an easy and reliable way to solve the long-term problem that has limited carbon nanotube application in mass integrated circuit production. Carbon nanotube alignment and bonding experiments are also conducted and the results are analyzed and discussed. The results show that the resistance of the carbon nanotube–metal interface reduces by 90% after bonding and the contact of the interface exhibits excellent endurance.

Numerical Simulation of Electromagnetic Induction Heating in the Material Heat Treatment

The paper firstly introduces the principle and mode of electromagnetic induction heating. Accordingly the basic equations of electromagnetic field and temperature field in the heating material are derived from Maxwell's equations and heat conduction differential equations. Then give an example of the electromagnetic induction heating. With the application of ANSYS software, the one-dimensional finite element model of the heating material is built. And numerically simulate it by the means of the electromagnetic field and temperature field coupling in the ANSYS software. The influence of the material's physical parameters changing with the temperature and significant skin effect in the electromagnetic induction heating are considered. So the results are correct and reliable.

Practical Application of Eddy Currents Generated by Wind

When a conductive material is subjected to time-varying magnetic fluxes, eddy (Foucault) currents are generated in it and magnetic field of opposite polarity as the applied one arises. Due to the internal resistance of the conductive material, the eddy currents will be dissipated into heat (Joule heating). Conventional domestic water heaters utilize gas burners or electric resistance heating elements to heat the water in the tank and substantial part of the energy to use for it is wasted. In this paper the origin of electromagnetic induction heat generated by wind turbine in special heat exchange camera connected to water boiler is discussed and material evaluation performed using mathematical modelling (comparing the 2D finite element model with analytical and numerical calculation results).

Fabrication of high chromium cast iron and medium carbon steel bimetal by liquid–solid casting in electromagnetic induction field

The high chromium cast iron and medium carbon steel bimetal was fabricated by liquid–solid casting in electromagnetic induction field. The interfacial structure and mechanical properties were investigated. The results show that the microstructure is refined obviously and mechanical properties are improved significantly. The electromagnetic stirring can refine effectively the microstructure, and profit the diffusion of elements and obtaining of the desirable microhardness transition. The electromagnetic induction heating is beneficial to achieving metallurgical interface bonding and improving the mechanical property. Furthermore, the electromagnetic stirring compels the molten metal to scour continuously the surface of medium carbon steel, resulting in the oxides and impurities being melted or broken away from the surface.

Electromagnetic induction heating of an orthopaedic nickel–titanium shape memory device

Shape memory orthopaedic implants made from nickel-titanium (NiTi) might allow the modulation of fracture healing, changing their cross-sectional shape by employing the shape memory effect. We aimed to show the feasibility and safety of contact-free electromagnetic induction heating of NiTi implants in a rat model. A water-cooled generator-oscillator combination was used. Induction characteristics were determined by measuring the temperature increase of a test sample in correlation to generator power and time. In 53 rats, NiTi implants were introduced into the right hind leg. The animals were transferred to the inductor, and the implant was electromagnetically heated to temperatures between 40 and 60°C. Blood samples were drawn before and 4 h after the procedure. IL-1, IL-4, IL-10, TNF-α, and IFN-γ were measured. Animals were euthanized at 3 weeks. Histological specimens from the hind leg and liver were retrieved and examined for inflammatory changes, necrosis, and corrosion pits. Cytokine measurements and histological specimens showed no significant differences among the groups. We concluded that electromagnetic induction heating of orthopedic NiTi implants is feasible and safe in a rat model. This is the first step in the development of new orthopedic implants in which stiffness or rigidity can be modified after implantation to optimize bone-healing.

EFFICIENCY AND INFLUENCING FACTORS OF ELECTROMAGNETIC STEEL--TEEMING TECHNOLOGY

A new method(electromagnetic steel-teeming method) using electromagnetic induction heating in slide-gate was proposed to overcome the disadvantage of the pollution of the traditional nozzle sand on the molten steel.The basic idea of this new process is to melt part of or the whole of the new ladle well-packing materials(i.e.Fe-C alloy with similar composition of the molten steel),which became the substitute of the traditional nozzle sand,and achieved smoothly molten steel-teeming. Experimental and numerical simulation methods were employed to investigate the surface temperature of the upper nozzle where the Fe-C alloy was used to replace the traditional nozzle sand.The calculated temperature is consistent with the experimental results.In addition,the effects of the induction parameters such as current intensity,frequency and diameter of the coil on teeming time were investigated. The results showed that the teeming time was decreased with the increases of current intensity and frequency,but with the decrease of coil diameter.The order of the factors affecting the teeming time is current intensity,frequency and diameter of the coil.The best parameters were found under the conditions of this research.The experimental results indicated that automatically teeming of the ladle would be achieved by using the electromagnetic steel-teeming technology.

Study on localized induction heating for wafer level packaging

Micro-electro-mechanical systems (MEMS) are being developed as a new multi-disciplinary technology, which will undoubtedly have a revolutionary impact on the future of human life. However, with the development of MEMS technology, the packaging has become the main technical obstacle to the commercialization of MEMS. An approach to MEMS packaging by high-frequency electromagnetic induction heating at wafer level is presented in terms of numerical simulation and experimental study. The structure of inductor is firstly designed and optimized. Then the heating situation of PCB board is verified. The results indicate that the heat impact on the chip during the packaging process can be effectively reduced by local induction heating packaging, therefore the thermal stress on the chip is considerably lowered. This method can effectively improve the reliability of the MEMS devices.

Introduction of electromagnetic induction heating technique into on-line chemical oxygen demand determination

A flow injection system incorporating electromagnetic induction heating oxidation for on-line determination of chemical oxygen demand (COD) was proposed. The procedure utilised electromagnetic induction heating instead of conventional reflux heating, with acidic potassium dichromate acting both as an oxidant and as a spectrometric reagent. The elevated temperature and pressure inside the reaction coil contributed to the improvement of on-line sample oxidation, and hence, sample oxidation time was reduced to ca. 8 min (as compared to 2 h required for conventional method). The sampling frequency was 10 h−1, along with a quantification limit of 4.0 mg L−1 COD and a linear range of 4–200 mg L−1 COD (potassium hydrogen phthalate, r = 0.9958). Relative standard deviation was evaluated to be 3.5% at 100 mg L−1 COD and the results were comparable to those obtained by the standard method.

유도가열 증기발생장치의 온도제어

제안한 유도가열 시스템은 증류탑 장치에 사용되는 특수적층 규칙충진체에 의한 열 교환기술과 IH(Induction-Heating)전자유도가열용의 특수한 고주파 전력회로 기술을 응용한 차세대 가열방식이다.<BR> 본 전자유도 유체가열기술은 IGBT대응의 고주파 인버터를 사용하여 상용교류로부터 수[㎑]의 고주파 교류를 발생시킬 수 있다. 공진형 고주파 인버터를 사용함으로 고성능, 고효율의 시스템화가 가능하다.<BR> 본 논문에서는 주파수 범위가 20[㎑]에서 44[㎑]인 고주파 공진형 인버터을 이용하여 증기를 발생시키는 유도가열시스템에 대해 제안한 온도제어에 대하여 기술하고자 한다.

Analysis of an Automatic Steel-teeming Method Using Electromagnetic Induction Heating in Slide Gate System

A new method (electromagnetic steel-teeming method) using electromagnetic induction heating in slide gate system was proposed to overcome the pollution of traditional nozzle sand on the molten steel and achieve 100% automatic steel teeming. By Joule heat, this new process is to melt part or the whole of a new ladle well-packing materials (i.e. Fe–C alloy particles with similar composition as the molten steel), which is the substitute for traditional nozzle sand. A numerical simulation method based on the integration of both electromagnetic and thermal analysis modules of ANSYS was employed to investigate the outside surface temperature change of the Fe–C alloy. In addition, the effects of the coil structural parameters (the distance between the molten steel and the coil, the length and the diameter of the coil) and electric current parameters (ampere-turns, frequency) on teeming time were investigated. Under the condition of the optimal parameters found according to simulation, the smoothly steel-teeming using induction heating was achieved. The safety of the steel shell under the action of electromagnetic induction heating with the optimal parameters was also checked via the distribution of temperature field on the shell.

Fabrication of Bioactive Apatite Nuclei Precipitated Titanium by Using Electromagnetic Induction Heating

Many micro pores were formed on the surface of a titanium (Ti) plate by sulfuric acid treatment, then apatite nuclei were precipitated in the pores of the Ti plate by direct heating of the plate by using electromagnetic induction in a simulated body fluid (SBF). When the Ti plate was soaked in SBF, amorphous calcium phosphate thin film covered the whole surface within 6 h and it grew into hydroxyapatite within 12 h. The hydroxyapatite layer showed high adhesive strength to the Ti plate due to a mechanical interlocking effect between hydroxyapatite grown in the micro pores and the Ti plate.

Computational Study of Electromagnetic Fields, Eddy Currents and Induction Heating in Thin and Thick Workpieces

A set of 2D steady state finite element numerical simulations of electromagnetic fields, eddy currents distribution and induction heating pattern has been done for different thicknesses of ametal workpiece. Comparison between the calculation results show the importance of workpiece thickness on induction heating process including electromagnetic field distribution, eddy currents pattern, heating structure and coil efficiency. PACS: 02.60.Cb, 02.70.Dh, 07.05.Tp, 81.05.Bx

A CLASS OF STATIONARY NONLINEAR MAXWELL SYSTEMS

We study a new class of electromagnetostatic problems in the variational framework of the subspace of W1,p(Ω) of vector functions with zero divergence and zero normal trace, for [Formula: see text], in smooth, bounded and simply connected domains Ω of ℝ3. We prove a Poincaré–Friedrichs type inequality and we obtain the existence of steady-state solutions for an electromagnetic induction heating problem and for a quasi-variational inequality modelling a critical state generalized problem for type-II superconductors.

Determination of Trace Inorganic Mercury in Mineral Water by Flow Injection On-line Sorption Preconcentration-Cold Vapor Atomic Fluorescence Spectrometry

Abstract Flow injection on-line sorption preconcentration and separation in a knotted reactor (KR) was coupled to cold vapor atomic fluorescence spectrometry for the determination of trace mercury in mineral water. Mercury was preconcentrated by on-line formation of mercury diethyldithiocarbamate complex (Hg-DDTC) and absorption of the resulting neutral complex on the inner walls of a knotted reactor. A 20% (v/v) HNO 3 solution heated by Electromagnetic induction heating technique was used as eluent to remove the absorbed Hg-DDTC from the KR, and then the vapor mercury generated by mixing the resulting solution and KBH 4 was determined on-line by cold vapor atomic fluorescence spectrometry. The 20% HNO 3 was used as both the efficient eluent and the required acidic medium for subsequent mercury vapor generation. Using 20% HNO 3 instead of conventional organic solvent as eluent, the proposed method is simple, easy operational and environmental friendly. Under the optimal experimental conditions, the sample throughput was approximately 30 per hour with the enhancement factor of 35. The detection limit of mercury was 2.0 ng l −1 . The precision (RSD, n = 11) was 2.2% at the 0.1 μg l −1 Hg 2+ level.

Compression Molding of Carbon Fiber Reinforced Thermoplastics Using Non-Woven Stitched Multi-Axial Cloth by Means of Induction Heating System

High-speed compression molding process of carbon fiber reinforced thermoplastics (CFRTP) by means of electromagnetic induction heating system (IH system) using non-woven stitched multi-axial cloth (NSMC) were proposed in this study. This IH system allows heating of the mold surface instantaneously. There is no need to preheat the mold and the material before placing it in the mold. This system can also reduce production cycle times and the cost of manufacturing composite parts. Specimens were molded by a traditional hot press processing and IH system. While the hot press processing required 50 minutes to raise the temperature of the mold from 50°C to 250°C, IH system required only 70 seconds. Mold cooling of the IH system finished in only about 150 seconds. Comparing with the traditional hot press processing, this IH system can reduce production cycle time drastically. The CF/polyamide 6 specimens molded by IH system had higher bending strength and better impregnation than these molded by the hot press processing. While the void content of specimens molded by the traditional hot press processing were more than 10%, specimens molded by IH system had only about 5% void content. In case of IH system, not only mold but also carbon fiber itself is heated by electromagnetic field. Since this heated carbon fiber accelerates the resin impregnation into the carbon fiber bundle, the void content of the specimens molded by IH system is smaller than that by hot press.

Variable mold temperature to improve surface quality of microcellular injection molded parts using induction heating technology

AbstractMicrocellular foam injection molding provides many advantages over conventional foams and their unfoamed counterparts, but its applications are limited by visible surface quality problems such as silver streaks and swirl marks. In this study, we propose a variable mold temperature method to improve the surface quality of molded parts. Electromagnetic induction heating is used in combination with water cooling to achieve rapid mold surface temperature control during the microcellular foam injection molding process. The effect of processing parameters, such as mold temperature, melt temperature, and injection velocity on the part surface quality, was investigated using surface roughness measurements and visual inspection of the molded parts. The results show that using induction heating to increase the mold surface temperature from 100°C to 160°C can decrease surface roughness of polycarbonate moldings from 25 µm to 6.5 µm. It was also found that the flow marks formed by gas bubbles on the part surface can be removed completely at a mold temperature of 160°C. Further increases in the mold temperature show slight improvements in the surface roughness up to 180°C, at which point the surface roughness starts to level off at 5 µm. This surface roughness value reflects an 80% improvement without a significant increase in cycle time over parts molded at a mold temperature of 60°C using water heating. Higher melt temperature and faster injection speed will also improve the surface quality of microcellular injection molded parts but not as significantly. The usefulness of a variable mold temperature in improving part surface quality during microcellular foam injection molding has been successfully demonstrated. © 2009 Wiley Periodicals, Inc. Adv Polym Techn 27:224–232, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20133

유도가열을 이용한 강판성형공정에서 유도코일 형상의 효과

Because of high intensity and easy controllability of the heat source, high frequency induction heating has been concerned and studied for the steel forming process in the ship building industry. However, the heating and forming characteristics have to be further properly modelled and analyzed for the process to be utilized with its optimal working parameters. In this study, a modelling with thermo-elasto-plastic analysis is performed using the FEM to study heat flow and deformation of the steel plate during the forming process with the electro-magnetic induction heating. The numerical model is then used to study the effect of the inductor shape on the magnitude of angular deformation of the plate during the forming process. It is revealed that the square shape of inductor induces the largest deformation among the rectangular inductors.

공진형 인버터를 이용한 2단 유도가열 시스템의 주파수제어에 관한 연구

제안한 유도가열 시스템은 증류탑 장치에 사용되는 특수충진체에 의한 열교환기술과 IH(Induction-Heating) 전자유도가열용의 특수한 고주파 전력회로 기술을 응용한 차세대 가열방식이다. 특히 일체의 연소과정이 없다는 점에서 작업환경의 개선이 가능하며 본 기술은 IGBT대응의 고주파 인버터를 사용하여 상용교류로부터 수[㎑]의 고주 파교류(HFAC)를 발생시킬 수 있다.BR 본 논문에서는 1.5[㎾]급 하프-브릿지 공진형 인버터 시스템과 공진부하의 동작해석, 특성분석 및 본 시스템을 이용한 2단가열 과열증기 발생장치의 개발과 시스템의 응용에 대해 논하였다.

On-line pressurized electromagnetic induction heating digestion: a promising sample preparation technique for trace mercury analysis

A novel, automated on-line pressurized sample digestion system based on electromagnetic induction heating technique was developed to perform solid sample decomposition in acid medium. The efficiency of acid digestion was increased with 0.36 MPa pressure built up in-line by a 0.5 mm id × 25 m length flow restrictor and up to approximately 135 °C reaction temperature. The system's performance was evaluated for on-line digestion of edible seaweeds and subsequent determination of mercury by cold vapor generation atomic fluorescence spectrometry (CVAFS).

Hot Tearing of Machinability Improved 2xxx Aluminum Alloy of High Tin Content with Manganese and Chromium Addition

In this study, the effect of Mn and Cr addition on high temperature mechanical properties of a machinable 2xxx alloy with high Sn content was systematically investigated. Tensile test during solidification was carried out, using an electromagnetic induction heating tensile test machine. Stress-strain curve, tensile strength, fracture strain (elongation), Zero Strength Temperature (ZST) and Zero Ductility Temperature (ZDT) were evaluated. To determine the solidification range of the 2xxx alloy with high Sn content, the specific heat were continuously measured in the range from room temperature to 700°C using an insulating type measuring device of specific heat. It was found that the tensile strength during solidification steeply increased with Mn and Cr addition, and the temperature range between ZST and ZDT became wider, in comparison with those without Mn and Cr addition. It was presumed that the crack susceptibility of the alloy increased by Mn and Cr addition. Fractography on the high temperature clearly distinguished the fracture property and fracture behavior of the alloys with and without Mn and Cr addition. Formation of intermetallic compounds at later stage of solidification was different from with and without Mn and/or Cr addition. Furthermore, by comparing the tensile strength with the casting practice, the effect of Mn and Cr addition on the crack susceptibility of direct-chill cast billets was severely attributed to crystallization of these compounds.