Induction Heating Process Research Articles

Mechanical and Microstructural Characteristics of 1.5 GPa-Grade Boron Steel by High-Frequency Induction of Eddy Currents

In the automobile industry, high-strength plates are increasingly used to reduce vehicle weight due to strict regulations on fuel efficiency and safety, and these plates achieve a tensile strength of 1500 MPa due to the hot-stamping process. Recently, research has been conducted to examine the flow behavior of materials according to the relationship between hot stamping time-temperature characteristics, coil shape, cooling method, and thermodynamic flow characteristics of quenching materials. In this study, a basic experiment in the form of a plate was conducted using an eddy current generated during high-frequency induction heating. It presents the surface temperature change, mechanical characteristics, and microstructure of boron steel that has undergone a high-frequency induction heating process. Surface temperature data were analyzed at different high-frequency induction heating forces (15, 18, 21, 24, 27, and 30 kW) and distances from specimens (6, 9, 12, and 15 mm). Two phases, austenite and ferrite, were formed in the low-temperature region, and martensite was formed in the high-temperature region. Mechanical properties and microstructures were also analyzed under different high-frequency induction heating coil conditions. The correlation between the high-frequency induction heating force and the specimen with the maximum tensile strength was investigated. Due to high-frequency induction heating, scale generation and surface decarbonization can be avoided. As a result of this experiment, 1500 MPa of the same tensile strength as the mechanical characteristics obtained in the existing heat treatment could be obtained.

Experimental investigation supported by artificial neural networks (ANNs) for predicting the heating performance of a cyclone separator coupled with induction heating coil

This paper proposes a novel dust separation and thermal inactivation system that couples an electromagnetic induction heating coil with a cyclone separator. The idea is aimed at the thermal inactivation of potential microorganisms (viruses and other pathogens) associated with dust-laden gas streams, particularly from road surfaces. The integrated system was tested in an experimental setup as a proof-of-concept investigation at different cyclone-induction heating temperatures of 100–400 °C (373–673 K) and air discharge flow velocities of 5–30 m/s. In addition, the influence of operating parameters such as cyclone heating temperature (as induction heating inputs), inlet air velocity, and heating time on the efficacy of the induction heating process were investigated. The time-averaged temperature measurements along the axial direction (z-down) showed predominant temperature fluctuations in the cylinder and cone sections for all cases, especially when the gas plummets down the cyclone. Temperature was highest in the conical section (z = 525 mm) at 320 °C (593 K) at 5 m/s and lowest in the outlet section (z = 375 mm) at 185 °C, which was expected. The results show that inlet air velocity plays a crucial role in affecting temperature dynamics. Conclusive results indicate that with increasing temperature, pressure drop decreases significantly. Along with the experimental results, multiple regression indices using an Artificial Neural Network (ANN) modeling were used to predict the cyclone’s induction heating performance, showing good prediction quality in terms of the mean square errors (MSE and RMSE) and the correlation coefficient R2: 0.99. The study demonstrates the technical viability of integrating induction heating coil to a cyclone separator for wide temperature applications.

Hybrid Neural Network Models for the Optimization of Induction Hardening Processes

We describe a simple hybrid methodology to simulate an induction heating process that combines observational (black-box) and physics-based (white-box) methodologies. This method uses a neural network to predict the process' physical characteristics, which were previously unknown. A primary emphasis is placed on monitoring temperature variations within a subsurface layer of a bolt sample. The hybrid model incorporates an ordinary differential equation for the heating rate, leading to improved data accuracy compared to a standalone black-box model. This innovative approach not only improves predictive precision but also simplifies interpretability, ultimately serving as a pivotal instrument for the effective management and advancement of induction heating operations.

Experimental and numerical investigations of induction heating for Ti-6Al-4V sheets and epoxy/carbon fiber composite laminates

The objective of this study is to present the electromagnetic and the thermal multi-field coupling model of the induction heating process for numerical simulation based on the finite element method. One of the most important difficulties encountered in the induction heating processes is to ensure homogeneous temperature distribution throughout the part. To improve the uniform temperature distribution in the sheet, the induction heating system is modelled with the ANSYS software taking into account some operational and geometrical parameters including current density and coupling distance between induction coil and sheet. Induction heating simulations were performed for all simulations at 20 kHz frequency ANSYS Maxwell. The numerical model has been verified by the conducted experiments for Ti6Al4V at the current of 50 A, 125 A, and 200 A, and the 1 mm and 3 mm gap distances. The relative error of the maximum temperature between the experiment and simulation was found around 14 % recorded at 25 s measurements. In addition, the effects of the current and the frequencies on the induction heating were evaluated by the verified numerical model for epoxy/carbon fiber (UD prepreg) and epoxy/carbon fiber (Woven prepreg) plates. The results show that the induction heating model is suitable and efficient to determine the temperature distribution within the thin plates by the finite element method.

A-site vacancy induced electronic engineering of perovskite for synergistic modulation of redox activity and magnetocaloric effect

Realizing “Power to Syngas” by electrifying chemical reactors via induction heating is one of the key enabling technologies to decarbonize the chemical industry. Nevertheless, developing catalysts for the induction heating process that can simultaneously serve as magnetic susceptors under high-temperature conditions remains challenging. Herein, we formulate a A-site vacancy induced electronic engineering strategy and, accordingly, synthesize a series of LaFe0.5Al0.5O3 perovskite catalysts with different amounts of La vacancies (VLa) (LFAO, 1.5 M-LFAO, and 3 M-LFAO). In this way, we tune both the redox activity and the magnetocaloric effect (MCE) of perovskite and, for the first time, achieve induction heating methane partial oxidation coupled with CO2 splitting for syngas production. Compared with the reported catalysts, the 3 M-LFAO had not only superior syngas and CO yields (101.84 L·kg cat−1/54.96 L kg cat−1) but also a great MCE (875 °C). Spectroscopic investigations and DFT calculations rationalize these observations and demonstrate that the VLa cause a unique Fe4+–O2-–Fe3+ configuration in perovskite, accounting for an upshift of Fe 3d and O 2p band centers and therefore enhancing redox activity and MCE. This work deepens the understanding of the relationship between catalysis and MCE and unlocks the novel guidance to design induction heating chemical processes.

Modelling the post‐buckling behaviour of steel sheets under induction heating

AbstractInduction heating has many engineering applications. To accurately describe the induction heating process of thin steel sheets one needs to account for their mechanical deformation. This might strongly affect the magnetic configuration since thin sheets are prone to thermal buckling, leading to large supercritical deformations. We suggest a modelling strategy combining a computationally highly efficient structural mechanical shell description for the thin sheet with a standard continuum model for eddy current and thermal problems through an iterative coupling algorithm. All benchmark problems are solved numerically using the finite element method.

Experimental activities for the study of transformation of electrical energy into thermal

In this article, three experimental practices involving transformations of electrical energy into thermal energy using the Joule effect, electromagnetic induction, and the Peltier effect were proposed. Furthermore, energy balance calculations and the demonstration of the induction heating process are performed using a zero voltage switching module coupled to an Arduino board. In this sense, the work verifies the pedagogical potential of the activities applied in two classes of the third grade of high school, in the face-to-face class format. A qualitative research methodology was adopted, and for data collection, questionnaires were used to survey the students’ prior knowledge, which, at the end of the activities, were applied again to identify a possible integrating reconciliation on the content. We hope that with this proposal, we can contribute to other Physics teachers, who can replicate these activities with their students, adapting it to their realities.

Simulation and experimental research on local continuous induction heating of inner corrugated section

The inner corrugated pressure-resistant shell has superior pressure resistance and can be formed by continuous rolling with corrugated rolls. However, there is a problem of excessive temperature drop during the rolling process. Meanwhile, lower rolling temperature leads to larger deformation resistance which affects plastic forming and increases the load of the rolling mill, which makes the size and shape control of the inner corrugated section more unstable. There is thickness variation in the inner corrugated section. The local supplementation and continuous induction heating of the inner corrugated section to complete the energy supplementation during the rolling of the inner corrugated section is an issue worthy of investigation. In this paper, Rectangular, profiling and anti-profiling coils were designed for the structure of the inner corrugated section, and continuous induction heating is carried out through the induction coil at the local position of the inner corrugated section. Based on the comparison of the simulation results, the heating efficiencies of rectangular coil, profiling coil, and anti-profiling coil were 46.39%, 75.07%, and 41.16%, respectively. The induction heating of the profiling coil is more efficient and uniform. Moreover, by optimizing the process parameters of profiling coil induction heating, the effects, caused by current, frequency, and air gap, on the induction heating results of the inner corrugated section were studied and analyzed, and the optimal profiling coil induction heating process parameters were obtained. Finally, an experimental platform for induction heating of the inner corrugated section was built. The induction heating experiment of the inner corrugated section was carried out by rectangular, profiling, and anti-profiling coil respectively. The experimental results were compared and analyzed, the heating efficiencies of rectangular coil, profiling coil, and anti-profiling coil were 47.88%, 84.14%, and 50.27%, respectively. The profiling coil had high heating efficiency and good uniformity.

Совместная оптимизация конструктивных параметров индуктора и алгоритмов управления процессом нагрева под поверхностную закалку

The paper considers an approach for solving the joint optimization problem of design solutions and modes 
 of inductor functioning in the process of heating steel parts of L-shaped form for surface hardening. The first stage solves the problem of optimizing the design of the coils of the inductor and the parameters of the power supply control algorithm, ensuring the maximum uniform heating of the quenched layer to a given temperature above the Curie point in 
 a fixed time. In the second step, a phase limitation is considered, which is a technological requirement to ensure, throughout the heating stage, a temperature not exceeding the limit value. In case of violation of the specified limit, the problem of finding the control algorithm on a special interval within which the maximum temperature in the hardened layer exceeded the maximum permissible value is solved. In the third step, the problem of joint optimization is solved with the found control algorithm at a specific interval of motion on the phase restriction. The described steps can be repeated if necessary. There is presented a test example of the application of the developed strategy for the considered class of technology induction heating for the surface hardening of metal blanks with an angle zone. For the numerical solution in the MATLAB application package developed a software complex, in which integrated two-dimensional nonlinear problem-oriented model of the induction heating process, developed in ANSYS Mechanical APDL. The algorithm for solving the joint optimization problem is based on an alternate method of parametric optimization of systems with distributed parameters. Developed strategy tested on a verified model of interconnected electromagnetic and temperature fields, it is possible to obtain a uniform temperature distribution along the boundary of the hardened layer of steel semi-finished products of complex geometric shape without local overheating throughout the heating stage.

Modeling and Simulation of a cooking inductors by Electromagnetic Induction

The fundamental concepts of induction heating have been discovered and applied to industrial processes since the 1920s. Its principle is based on the direct application of two physical laws, Lenz's law, and the Joule effect. The development of electromagnetic induction principles in cooking systems is progressing, as they offer better working conditions, good safety, high energy efficiency, and low pollution. Induction heating is the transmission of electromagnetic energy through the surface of a heated material via three physical phenomena: permeability, electrical conductivity and thermal conductivity, depending on temperature. This electro-thermal technique permits electrical conductive materials to be heated without physical contact with an electrical source. In particular, the study of the inductor position in the heating plate can improve and normalize the induction heating temperature. In this work, we proposed several geometries for cooking inductor position based on numerical modeling of induction heating processes using the finite element method on Matlab to solve all electromagnetic problems. The chosen geometrical model with 3 inductors has a good temperature distribution in the heating plate of about 650 K (377 C).

Method of Determining the Temperature Characteristics of the Thermal and Electrical Properties of Conductive Materials on a Stand for Induction Heating

In induction heating processes, knowledge of the charge material parameters, i.e., thermal conductivity and volumetric heat capacity, as well as resistivity and magnetic permeability, is important both at the stage of preparatory process simulations and during their implementation. The paper presents a measurement method for estimating the thermal diffusivity, volumetric heat capacity, and resistivity of the charge material as a function of temperature on a single measuring setup, using a generator for induction heating as the source of signals. The method is based on the study (for forced temperature levels) of the temperature responses of cylindrical samples of the test materials and the voltage induced in the designed measuring coil after short- or long-term step excitation impulses. The presented approach enabled the dedicated computer-controlled system to obtain the initial values of the searched parameters with an accuracy of several percent. The procedure constitutes an introductory step in the simultaneous determination of a set of searched characteristics, and, by performing measurements, significantly narrows the range of variability in the decision variables of the optimization process.

Amaiur Mendi Altube - Electro-thermal modelling of an induction heating process for industrial applications

Amaiur Mendi Altube - Electro-thermal modelling of an induction heating process for industrial applications

Development of productive curing processes for the manufacturing of adhesively bonded milling tools

ABSTRACT The use of adhesive bonding in the milling tool industry has been reported as advantageous, when compared with the industry’s standard, i.e. brazed joints. This work focuses on improving a previously developed jigless manufacturing process – i.e. induction pre-curing – used to produce woodworking tools. To reduce production times, two tactics were employed to accelerate the induction process. Different coil geometries, changing the magnetic field intensity, and a ferromagnetic filler, promoting internal heat generation. It was found that these methods do not improve the heating process in a significant way. Therefore, the standard alternative, i.e. full oven curing, was also tested. Using small-scale real joint specimens, the shear resistance of both curing procedures was compared. This revealed that oven curing provides two times more strength. As such, a new joint geometry was developed, to facilitate the process of oven curing full milling tools, now fabricated with fixing jigs. In conclusion, the induction heating process was deemed unfeasible, and, as such, oven curing became the recommended method. Several milling tool prototypes were manufactured and validated both in laboratory and real-world conditions, through costumer focused testing. These tests showed good tool performance and workpiece surface quality.

Разработка конструкции индуктора для закалки детали сложной формы

Due to active process of import substitution, domestic industry starts producing the parts previously purchased abroad. These parts are necessary for stable and reliable operation of various technical objects and systems. Thus, the development of a technological installation for hardening a metal profile is topical. The task is complicated by the fact that the profile has very thin irregularly shaped walls, which should be hardened only from the inside, while the outer wall of the profile should be heated minimally to maintain strength. The studies have been carried out on simulation models of electromagnetic and thermal fields, which make it possible to reproduce the process of induction heating of the research object. Since the part has the same shape along the entire length, the simulation of the process of its induction heating is performed in two-dimensional space. The authors have developed a simulation model of the process of induction heating of a part of a non-standard shape, which includes calculations of thermal and electromagnetic fields. The design of the inductor is proposed, supplemented with ferrite inserts, which makes it possible to achieve the temperature regime necessary for the hardening process. The developed simulation model makes it possible to evaluate the distribution of the thermal and electromagnetic fields of the part, thereby predicting getting the temperatures required for its hardening when using various designs of inductors. The results of numerical experiments are consistent with the physical concepts of induction heating and prove the possibility to use induction hardening for thin-walled parts of complex shape instead of laser hardening used for this type of parts. The proposed model can be used in engineering practice to design inductors of non-standard parts.

Insights into Induction Heating Processes for Polymeric Materials: An Overview of the Mechanisms and Current Applications

In polymer systems, induction heating (IH) is the physical outcome that results from the exposure of selected polymer composites embedding electrically-conductive and/or ferromagnetic fillers to an alternating electromagnetic field (frequency range: from kHz to MHz). The interaction of the applied electromagnetic field with the material accounts for the creation of magnetic polarization effects (i.e., magnetic hysteresis losses) and/or eddy currents (i.e., Joule losses, upon the formation of closed electrical loops), which, in turn, cause the heating up of the material itself. The heat involved can be exploited for different uses, ranging from the curing of thermosetting systems, the welding of thermoplastics, and the processing of temperature-sensitive materials (through selective IH) up to the activation of special effects in polymer systems (such as self-healing and shape-memory effects). This review aims at summarizing the current state-of-the-art of IH processes for polymers, providing readers with the current limitations and challenges, and further discussing some possible developments for the following years.

Numerical Study of Ti6Al4V Alloy Tube Heated by Super-Frequency Induction Heating.

Ti6Al4V alloys have a narrow processing window, which complicates temperature control, especially during large-scale production. Therefore, a numerical simulation and experimental study on the ultrasonic induction heating process of a Ti6Al4V titanium alloy tube were conducted to obtain stable heating. The electromagnetic and thermal fields in the process of ultrasonic frequency induction heating were calculated. The effects of the current frequency and current value on the thermal and current fields were numerically analyzed. The increase in current frequency enhances the skin and edge effects, but heat permeability was achieved in the super audio frequency range, and the temperature difference between the interior and exterior of the tube was less than 1%. An increase in the applied current value and current frequency caused an increase in the tube's temperature, but the influence of current was more prominent. Therefore, the influence of stepwise feeding, reciprocating motion, and stepwise feeding superimposed motion on the heating temperature field of the tube blank was evaluated. The coil reciprocating with the roll can maintain the temperature of the tube within the target temperature range during the deformation stage. The simulation results were validated experimentally, which demonstrated good agreement between the results. The numerical simulation method can be used to monitor the temperature distribution of Ti6Al4V alloy tubes during the super-frequency induction heating process. This is an economical and effective tool for predicting the induction heating process of Ti6Al4V alloy tubes. Moreover, online induction heating in the form of reciprocating motion is a feasible strategy for processing Ti6Al4V alloy tubes.

Digital Twins of Induction Heating Processes in the Metallurgical Industry

Digitalization of induction heating systems in metallurgy passes the way from digital simulation of electromagnetic fields to the construction of digital twins. The main stages in the evolution of digital simulation, including computational experiments and the development of digital twins of induction heating systems, are considered. The main features in the development of digital twins have been identified. Efficient methods for computing electromagnetic fields in induction heating devices and principles for constructing multiphysical models, including the most important electrothermal models, have been developed. A package of dedicated computer programs for simulating not only induction heating devices, but also technologies involving the use of induction heating has been developed. A close relationship between optimal design and control of induction heaters is shown. Examples of building digital twins of various systems with the use of induction heating are given.

Microstructure Observation around Hardness Transition Area of Repeated Induction Heated S45C Shaft

It had been reported that repeated induction heating process decreased the prior austenite grain size and refined the martensitic structure of JIS SUJ2 samples. In the present work, we compared hardness values and structures of hard surface and soft core of three-times repeated induction heated and once tempered (IH Q3T1) JIS S45C steel bar specimen and once induction heated and once tempered (IH Q1T1) bar. Structures consist of three areas: Hard; Transition; and Soft Core Areas. Martensite, ferrite and martensite, and ferrite and pearlite were observed at the Hard, Transition, and Soft Core Areas. From these observations, it was found that ferrite ratio increased with depth from the surface, and repeated induction heating had little effect on the hardness distribution and internal structure.

Investigation of Induction Heating Process for Selective Melting of Aluminum Alloy for the Repair of Exit Hole Defect in Friction Stir Welding Process

Investigation of Induction Heating Process for Selective Melting of Aluminum Alloy for the Repair of Exit Hole Defect in Friction Stir Welding Process

A Development of an Induction Heating Process for a Jewelry Factory: Experiments and Multiphysics

This article reports a successful development of the induction heating process (IHP) in a jewelry factory based on experiments and multiphysics consisting of electromagnetic and thermal simulations. First, two experiments were set to measure essential parameters for result validation and multiphysics boundary condition settings. Then, the essential parameters were applied to multiphysics, and both simulation results revealed heat transfer, magnetic flux density (B) generated by the coil, and temperature (T) of the product. B and T were consistent with the experimental results and theory, confirming the reliability of the multiphysics and methodology. After that, all simulation results were analyzed to assess and optimize IHP in terms of the number of coil turns (N), positional placement of the product (P), and coil thickness (Th). Multiphysics revealed that the current operating condition with N = 3 is proper; however, the IHP can be improved more with coil and operating condition optimizations. Finally, completing the optimizations, decreasing 40% of Th with N = 6, and the same P, increased B on the product by 21.62%, leading to IHP efficacy enhancement. The research findings are the optimum coil model and methodology for developing the IHP, which were practically employed in the jewelry factory.