High Frequency Induction Heating Research Articles

Development of Energy Saving Technologies for Steel Wire Heat Treatment

This article presents the development of energy-saving induction heating technology to accelerate significantly the process of heat treatment of steel wire. The analysis of international trends and prospects of the use of induction heating shows a steady expansion of the applied induction technologies in metallurgy. The article considers the advantages of induction heating in comparison with other competitive technologies. Heat treatment in electro-technical induction units is determined by the interrelated electrical and thermal processes in them, the complex nature of the distribution of internal heat sources, the dependence of the nature of the power distribution of the induction unit on the temperature of the products processed. The features of the applicated in the induction method of heating in the hardware industry for objects previously unused: such as coils of wire and riots of calibrated steel. The results of the study show the influence of the induction method of heating on temperature-time factors to the formation of the structure, to increase the uniformity of heating and the quality of heat treatment of steel wire, calibrated steel in riots, taking into account the technological problem. The authors give the assessment of the effectiveness of medium and high-frequency induction heating of steel wire of various diameters. The evaluation of the increase in the efficiency of an induction heating unit with the simultaneous heat treatment of several filaments of steel wire of the same diameter, combined into a bundle, was made.

Correction to: Advancement in the Pressureless Sintering of CP Titanium Using High-Frequency Induction Heating

The article “Advancement in the Pressureless Sintering of CP Titanium Using High-Frequency Induction Heating”, written by Stella Raynova, Yan Collas, Fei Yang, and Leandro Bolzoni was originally published Online First without Open Access. After publication in volume 50A, issue 10, page 4732 the author decided to opt for Open Choice and to make the article an Open Access publication. Therefore, the copyright of the article has been changed to © The Author(s) 2019 and the article is forthwith distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits use, duplication, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made

高周波誘導加熱エネルギー入出力の線形性に着目した「機能性評価法」による汎用モーター部品生産プロセスの最適化

高周波誘導加熱エネルギー入出力の線形性に着目した「機能性評価法」による汎用モーター部品生産プロセスの最適化

Characteristic Evaluation of Coaxial High-Frequency Induction Heating Hybrid Friction Stir Welding Process on High Strength Carbon Steel Sheets

The thermo-mechanical properties of high strength steel limit the use of the friction stir welding(FSW) process in terms of quality and productivity. In this study, hybrid FSW(HFSW) using coaxial induction heating was designed to be applied to high strength steel and to ensure directional flexibility. The performance and characteristics of the HFSW process were evaluated on 590 and 980 dual phased high strength steel. The range of welding speeds adequate for the FSW and HFSW processes were compared, to evaluate the productivity of the HFSW process. During FSW, system deflection, vertical load and torque were measured to understand the process behavior. In HFSW, welding speeds were increased by 75% and 50%, respectively, for 590 DP and 980 DP steels compared to the conventional FSW processes. Furthermore, a relatively deeper heat-affected zone was achieved. The deeper heat-affected zone was produced by deeper tool plunging depth due to reduced system deflection. Earlier stabilization of the vertical load and torque is another feature of HFSW, due to the preheating effect. Employing the HFSW process, with its simple system configuration and process flexibility, can improve productivity and quality for welding high strength steels. Key words: Coaxial high-frequency induced heating, Friction stir welding, Dual phased high strength steel, Welding speed, Vertical load, Torque

Synthesis of powder metallurgy Ti-3Fe-2Al alloy using high-frequency induction heating

A powder metallurgy approach was applied for the synthesis of an [Formula: see text] Ti-2Al-3Fe alloy. Blends of the elemental Ti, Al and Fe powders were compacted and subsequently sintered. High-frequency induction heating (HFIH) instead of conventional high-vacuum furnace heating was used for the sintering, due to its high efficiency. The effect of temperature on the level of densification, residual porosity and mechanical properties was studied. Electron dispersive spectrum analysis was used to study the dissolution and homogenization of the alloying elements. The results showed that a short induction sintering (IS) cycle in the range of 10–15 min is sufficient to achieve significant powder consolidation, evident by the increase of the density and mechanical properties. The residual porosity diminishes with the increase of the sintering temperature. Full dissolution of the alloying powders is completed after sintering at temperatures above those of [Formula: see text]- to [Formula: see text]-phase transformation.

Mechanical Properties and Fabrication of a Nanostructured Nb-Al2O3 Composite by High Frequency Induction Heating

Al2O3 has a high Young’s modulus (380 GPa), a low density (3.98 g· cm-3), good high-temperature mechanical properties, biocompatibility and excellent oxidation resistance. Al2O3 has been used for automotive, aerospace, bio-materials and various industrial applications. Despite its various merits, the low fracture toughness of the material below the brittle-ductile transition temperature has limited its use for wide application. To enhance its fracture toughness, the method commonly utilized has been to make a composite by the addition of a second phase to fabricate nanostructured materials. In the study, nano-powders of Al2O3 and Nb were synthesized during the ball milling according to the reaction(Nb2O5 + 10/3 Al → 2Nb + 5/3 Al2O3). The nanostructured Nb-Al2O3 composite was consolidated within a short time from the milled powders using high-frequency induction heated sintering. The average grain sizes of Al2O3 and Nb in composite sintered at 1400 °C were 63 and 250 nm, respectively. The relative density of the Nb-Al2O3 composite was about 99% under the simultaneous induced current and application of 80 Mpa pressure. The fracture toughness and hardness of the composite were about 8.7 MPa· m1/2 and 1460 kg/mm2, respectively. The fracture toughness of the nanostructured Nb-Al2O3 composite was higher than that of monolithic Al2O3. (Received June 7, 2019; Accepted September 10, 2019)

High-frequency induction heating for increase of flow length in polymer/metal hybrid molding

Recent trends of miniaturization and multi-functionality in electrical parts have driven development of molded interconnect devices (MIDs) that contain conductive tracks on a nonconductive base. This study aims to develop polymer/metal hybrid molding technology to fabricate MIDs in a single manufacturing process, without an additional assembly procedure. For this purpose, injection molding was performed to fabricate a thermoplastic carrier that contained negative circuit channels, and die casting was used to fill the circuit channels with metal alloy of low melting point. To increase the flow length of the molten metal through the narrow circuit channel, high-frequency induction heating was used prior to the die casting stage. The effect of heating conditions on the mold temperature was investigated numerically, and the relevant induction heating conditions were determined accordingly. Induction heating was then applied to the die casting process to increase the flow length enough to be used as a circuit path for fabrication of MIDs.

High-frequency induction heating of shrink-fitting parts of turbogenerators

The advantages and disadvantages of induction heating by high-frequency currents during large-sized parts mounting and dismounting are studied. The deviations of the temperature field and the deformation field of the part from the axial symmetry with the horizontal position of the shaft are analyzed. Recommendations were developed on how to take into account these deviations in the technology of mounting and dismounting of the retaining rings of turbogenerators.

Evaluation of a High-Frequency Induction Heating Assisted Friction Stir Welding Process on Carbon Steel Sheets

Friction stir welding of carbon steel causes tool wear and system deformation issues because of its relatively high strength compared to aluminum. As a countermeasure, additional high-frequency induction heating is suggested to solve this problem. An inline high-frequency induction heating assisted friction stir welding process was studied on 450 MPa and 980 MPa grade carbon steel sheets. As a pre-experiment, the heating performance of the high-frequency induction heating system was quantified. Then the effective welding speed range, vertical load history, and weldment performance were investigated to evaluate the characteristics of the process. Those results were compared with a conventional friction stir welding process conducted under equivalent process conditions. For the 440 MPa steel, about 40% faster maximum welding speed was achieved by applying the 4 kW induction heating. No tensile strength degradation of the weldment was found. Also, the maximum vertical load was decreased by 26% compared to the conventional friction stir welding process. No significant degradation of hardness was observed in the welds on 440 MPa and 980 MPa steel. Key words: High-frequency induced heating, Friction stir welding, Carbon steel, Welding speed, Vertical load

The Microalloying Effect of Ce on the Mechanical Properties of Medium Entropy Bulk Metallic Glass Composites

Novel ultra-strong medium entropy bulk metallic glasses composites (BMGCs) Fe65.4−xCexMn14.3Si9.4Cr10C0.9 and Ti40−xCexNi40Cu20 (x = 0, 1.0), through the martensite transformation induced plasticity (TRIP effect) to enhance both the ductility and work-hardening capability, were fabricated using magnetic levitation melting and copper mold suction via high frequency induction heating. Furthermore, the Ce microalloying effects on microstructure and mechanical behaviors were studied. The Fe-based BMGCs consisted of face-centered cubic (fcc) γ-Fe and body-centered cubic (bcc) α-Fe phase, as well as Ti-based BMGCs containing supercooled B2-Ti (Ni, Cu) and a thermally induced martensite phase B19’-Ti (Ni, Cu). As loading, the TRIP BMGCs exhibited work-hardening behavior, a high fracture strength, and large plasticity, which was attributed to the stress-induced transformation of ε-Fe martensite and B19’-Ti (Ni, Cu) martensite. Ce addition further improved the strengthening and toughening effects of TRIP BMGCs. Adding elemental Ce enhanced the mixing entropy ΔSmix and atomic size difference δ, while reducing the mixing enthalpy ΔHmix, thus improving the glass forming ability and delaying the phase transition process, and hence prolonging the work-hardening period before fracturing. The fracture strength σf and plastic stress εp of Ti39CeNi40Cu20 and Fe64.4CeMn14.3Si9.4Cr10C0.9 alloys were up to 2635 MPa and 13.8%, and 2905 MPa and 30.1%, respectively.

One-step rapid preparation of CuO nanosheets by high frequency induction heating and the application as excellent electrochemical sensor based on CuO/MWCNTs for the detection of glucose

In this study, to improve production efficiency, a simple and rapid synthesis method of copper oxide (CuO) nanosheets by using high frequency induction heating was proposed. The CuO nanosheets were successfully prepared, and formulated into CuO and CuO/Multi-walled carbon nanotube (MWCNTs) electronic ink. After characterizing of the morphology, composition and structure of the as-prepared CuO nanosheets, the non-enzymatic glucose sensors by using CuO nanosheets and CuO/MWCNTs as functional materials were fabricated by dispensing on screen printed graphite electrodes (SPGE). For the detection of glucose, the electrochemical properties of the fabricated electrochemical sensor were evaluated by cyclic voltammetry (CV) and chronoamperometry. The results showed that the prepared electrochemical glucose sensor by CuO and CuO/MWCNTs all exhibited excellent sensitivity (1290 μAmM−1cm−2, 1890 μAmM−1cm−2), wide linear range (4–400 μM), and low detection limit (0.21 μM, 0.14 μM), high selectivity to common interference in physiological fluids, high stability and excellent feasibility for actual sample analysis. Between them, the electrochemical properties of the sensor prepared from CuO/MWCNTs are better due to the excellent electronic conductivity of MWCNTs.

Advancement in the Pressureless Sintering of CP Titanium Using High-Frequency Induction Heating

High-frequency induction heating is applied as an alternative heating source for pressureless sintering of commercially pure Ti powders, aiming to intensify the sintering process. The effects of the process parameters on the properties of the sintered material are systematically studied. The initial powder compact density is the most influential parameter permitting sintered structures with highly porous to almost fully dense appearance. Short heating time combined with sintering to temperatures just above the β-transus resulted in a strong diffusion bonding between the Ti powder particles, and grain growth is observed at the former boundaries of the neighboring powder particles. The dimpled appearance of the fracture surface at those regions confirmed the strong metallic interparticle bonding. Tensile properties comparable to those of Ti-Grade 3 and Ti-Grade 4 are achieved, which also demonstrates the efficiency of the induction sintering process. A mechanism explaining the fast and efficient sintering is proposed. The process has the added advantage of minimizing the oxygen pickup.

Formability Analysis and Oxidation Layer Effects in Dieless Drawing of Stainless Steel Wires

In this study, dieless drawing experiments of stainless steel SUS304 wires of 1 mm in diameter were carried out using a self-developed dieless drawing machine. In order to prevent oxidation, argon gas was applied to a self-designed chamber during dieless drawing processes. The effects of the forming temperature and the oxide layer on the mechanical properties of the drawn SUS304 stainless wires obtained by tensile tests are discussed in this paper. A finite element model considering the high frequency induction heating mode in the finite element software DEFORM2D was developed to conduct the heat transfer analysis and the formability analysis of the drawn products in dieless drawing of stainless steel wires. The effects of the drawing speed and forming temperature on the maximal reachable area reductions are discussed. Through the comparisons of the maximal reachable area reduction between the finite element simulations and experiments, the finite element modelling for dieless drawing processes was validated.

The study of the temperature field in pebble beds with volumetric heating and radial flow of coolant

The paper presents the results of an experimental and numerical study of hydrodynamics and heat transfer in a pebble bed with internal volumetric heat release. An experimental setup was designed to investigate the hydrodynamics and heat transfer at the radial flow of a single-phase coolant. The pebble bed was set from 2.0 mm diameter sphere made of AISI 420 steel. The internal heat release model in the pebble bed is provided by high-frequency induction heating, whereby the thermal power of the high-frequency installation is 20 kW. The experiments were carried out in the range of mass flow rates of 0.1 - 0.6 kg/s. The test section simulates the fuel assembly of a nuclear reactor with microfuel. Pebbles are placed between the inner and outer perforated covers. Radial coolant flow is achieved to minimize pressure losses. The inner cover is cone-shaped and is the dispensing manifold for the coolant. The conical shape of the cover provides a uniform flow rate of the cooling liquid along the length of the test section. The temperature distribution in the pebbles were recorded.

Numerical Simulation of Metal Surface Layer Modification Using High-Frequency Induction Heating

Thermal processes of modifying the surface layer of a metal in a moving substrate with continuous induction heating of a rectangular substrate region by a high-frequency electromagnetic field have been studied using numerical simulation. The distribution of electromagnetic energy over the substrate surface is considered uniform, and over its volume, it is described by empirical formulas. It is assumed that, during the melting of the metal, the nanosized particles of the refractory compound inside of it are evenly distributed over the volume of the liquid metal and act as crystallization centers during its cooling. The boundary of the melting region is determined in the Stefan approximation, and the boundaries of the solid phase growth region are computed within the framework of the Kolmogorov theory of the metal crystallization. In the quasi-stationary distribution of the temperature field approximation, the size of the melting and crystallization zones was estimated and the growth kinetics of the solid phase was calculated. The characteristics of induction heating that make it possible to reduce the surface treatment time were determined. Calculated estimates of the specific power of the electromagnetic field were obtained that ensures that the melting region remains unchanged at the substrate velocity in the range of 1–3 cm/s.

Ceramic nanofibers versus carbon nanofibers as a reinforcement for magnesium metal matrix to improve the mechanical properties

Light composite materials based on Magnesium matrix reinforced with carbon or ceramic nanofibers were fabricated by powder metallurgy rout using high frequency induction heat sintering (HFIHS) technique. A comprehensive comparative study has been investigated on using ceramic nanofibers and carbon nanofibers as a fibers reinforced Magnesium metal matrix in order to evaluate the overall improvements in mechanical properties. Electrospinning technique followed by calcination process were used efficaciously to synthesize and fabricate the Titanium Oxide (TiO2) fibers and carbon fibers. Mg/nanofibers mixtures were prepared via powder metallurgy route using mechanical alloying technique by adding 1, 3, 5 and 10 wt% calcined nanofibers to Mg matrix. In inert atmosphere and room temperature, mixtures were initially processed using high energy ball milling for 15 + 15 min. The final bulk cylindrical samples were obtained by performing consolidation or sintering process using high frequency induction heat sintering furnace (HFIHS). Characterization of the sintered composites have been investigated using field emission scanning electron microscopes (FESEM), energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). While, hardness test and compression test were performed in order to evaluate the mechanical properties of the fabricated composites. The obtained result shows that, the ultimate compressive strength increased to 281 MPa at 5 wt% TiO2, which represent about 12.4% more than the pure Mg. Hardness improved up to 64.4% in case of using the ceramic nanofibers as reinforcement. While using CNFs as reinforcement to the Mg matrix, slightly deteriorates the mechanical properties.

Transient Liquid Phase Bonding of Ti-6Al-4V and Mg-AZ31 Alloys Using Zn Coatings.

Ti-6Al-4V and Mg-AZ31 were bonded together using the Transient Liquid Phase Bonding Process (TLP) after coating both surfaces with zinc. The zinc coatings were applied using the screen printing process of zinc paste. Successful bonds were obtained in a vacuum furnace at 500 °C and under a uniaxial pressure of 1 MPa using high frequency induction heat sintering furnace (HFIHS). Various bonding times were selected and all gave solid joints. The bonds were successfully achieved at 5, 10, 15, 20, 25, and 30 min. The energy dispersive spectroscopy (EDS) line scan confirmed the diffusion of Zn in both sides but with more diffusion in the Mg side. Diffusion of Mg into the joint region was detected with significant amounts at bonds made for 20 min and above, which indicate that the isothermal solidification was achieved. In addition, Ti and Al from the base alloys were diffused into the joint region. Based on microstructural analysis, the joint mechanism was attributed to the formation of solidified mixture of Mg and Zn at the joint region with a presence of diffused Ti and Al. This conclusion was also supported by structural analysis of the fractured surfaces as well as the analysis across the joint region. The fractured surfaces were analyzed and it was concluded that the fractures occurred within the joint region where ductile fractures were observed. The strength of the joint was evaluated by shear test and found that the maximum shear strength achieved was 30.5 MPa for the bond made at 20 min.

Effect of Heating Spacing on Deformation Distribution of Line Heating Process

Ship hull plate forming with line heating technique is an important process in the shipbuilding industry. An automatic line heating control system needs an accurate database of various processing parameters. In this study, a numerical model, calibrated and verified using experiment results, was used to study the deformation distribution of a plate corresponding to different heating line spacing. This paper presents the results based on a single-torch and multiple-torch process. The deformation distributions in the heating and nonheating regions were analyzed. The impacts of coupling effect among heating lines were deliberated. 1. Introduction Line heating is an efficient plate forming process for many applications, such as ship hull forming, molding car body, and other curved objects. In the shipbuilding industry, this method is mainly used to create double-curved ship hull plates, especially for those plates near the bow and stern. Line heating is a complex nonlinear thermal process that involves thermodynamics, elastic-plastic mechanics, and metallurgy. Many researchers have conducted studies on the mechanism of line heating process to predict the final shape of the metal plate according to the heating conditions and mechanical properties of the plate (Moshaiov & Vorus 1987; Ueda et al. 1994a, 1994b, 1994c; Ji & Liu 2001); others performed numerical analysis with thermal elastic-plastic models to determine the parameters in line heating process (Jang et al. 1997; Yu et al. 1999,2001; Yu 2000; Wang et al. 2006). Many experimental works were carried out to verify the thermal elastic-plastic models (Moshaiov & Shin 1991; Liu et al. 2006; Zhou et al. 2014a). The effects of parallel and cross heating lines were discussed recently (Zhou et al. 2014b; Vega et al. 2015). Residual stress among the steel plate was studied to reveal the relationship of different heating conditions. Different heat sources have been used in line heating process, and they include gas torch(Tomita et al. 2001; Jong & Jong 2003), laser beam (Kyrsanidi et al. 1999), welding arc (Kitamura et al. 1996), and high-frequency induction heating (Ogawa et al. 1994; Lee & Hwang 2014). In all heat sources, gas torch is most frequently used as it was and still is the cheapest and most readily available heating source in most shipyards.

Thermal stability of nanocrystalline Al−10Fe−5Cr bulk alloy

Abstract Thermal stability of nanocrystalline Al−10wt.%Fe−5wt.%Cr bulk alloy was investigated. The initial micro-grained mixture of powders was processed for 100 h using mechanical alloying (MA) to produce nano-grained alloy. The processed powders were sintered using high frequency induction heat sintering (HFIHS). The microstructures of the processed alloy in the form of powders and bulk samples were investigated using XRD, FESEM and HRTEM. Microhardness and compression tests were conducted on the bulk samples for evaluating their mechanical properties. To evaluate the thermal stability of the bulk samples, they were experimented at 573, 623, 673 and 723 K under compression load at strain rates of 1×10−1 and 1×10−2 s−1. The annealed samples exhibited a significant increase in their microhardness value of 2.65 GPa when being annealed at 723 K, as compared to 2.25 GPa of the as-sintered alloy. The bulk alloy revealed compressive strengths of 520 MPa and 450 MPa at 300 K and 723 K, respectively, when applying a strain rate of 1×10−1 s−1. The microstructural stability of the bulk alloy was ascribed to the formation of iron and chromium containing phases with Al such as Al6Fe, Al13Fe4 and Al13Cr2, in addition to the supersaturated solid solution (SSSS) of Cr and Fe in Al matrix.

Separation behavior of metal-resin composite film using high frequency induction heating

Waste flexible printed circuit (WFPC) contains a number of precious resources such as base and noble metals. In this research, we propose a new separation / recovery technology using high frequency induction heating as a recycling process of WFPC. The peeling strength of the sample heated by high frequency induction heating was quantitatively evaluated using a tensile tester, and the effect of sample dimensions and heating conditions on adhesive properties was experimentally investigated. As a result of the high frequency induction heating experiment, it became clear that the coil current when the FPC simulated sample is peeled decrease with increase in heating area and decrease in sample thickness. As a result of the tensile test, there was a difference in peeling behavior between the unheated sample and the heated sample. It was found that the peeling tensile force of the heated sample increased with increase in the coil current. In addition, the peeling tensile force showed a tendency to decrease after reaching the maximum. Ultimately, the peeling tensile force of the sample heated at the critical current value was decrease than that of the unheated sample.