Rapid Induction Heating Research Articles

Microstructural Evolution During Rapid Induction Heating and Hardening of Microalloyed 1045 Medium Carbon Steels: Effect of Initial Microstructure

Microstructural Evolution During Rapid Induction Heating and Hardening of Microalloyed 1045 Medium Carbon Steels: Effect of Initial Microstructure

Enhanced strength-plasticity synergy of 304 stainless steel by introducing gradient nanograined single austenite phase structure via USRP and induction annealing

Enhanced strength-plasticity synergy of 304 stainless steel by introducing gradient nanograined single austenite phase structure via USRP and induction annealing

Investigation on Improvement of Magnetic Properties of Semi Processed Materials by using High-Temperature and Rapid Low-frequency Induction Heating

Investigation on Improvement of Magnetic Properties of Semi Processed Materials by using High-Temperature and Rapid Low-frequency Induction Heating

Synergetic improvements in surface hydrophobicity and wear resistance of TC4 materials via the combination of rapid heating and EtOH quenching methods

Synergetic improvements in surface hydrophobicity and wear resistance of TC4 materials via the combination of rapid heating and EtOH quenching methods

Influence of process conditions on the mechanical and microstructural features of milled Al sintered with rapid heating

Influence of process conditions on the mechanical and microstructural features of milled Al sintered with rapid heating

Process Design for Manufacturing Fiber-Reinforced Plastic Helical Gears Using a Rapid Heating and Cooling System

In this study, a lightweight fiber-reinforced plastic (FRP) helical gear was fabricated to investigate the potential application of FRP in automobile parts that require high loads and reduced noise. High-performance aramid FRP processed using the wet-laid method was used in the tooth region, and SCR420 steel was used in the inner hub region. A hot-forming system that combines rapid induction heating and water channel cooling methods was developed to reduce the cycle time. The cooling water flow conditions were analyzed to precisely control the mold temperature. Additionally, a rotating extraction system was developed to mitigate the extraction difficulty owing to the helix angle to the extraction direction. Using the innovative hot-forming system developed in this study, a helical gear without any process-induced defects was fabricated with a significantly reduced cycle time. The performance of the gear was successfully estimated using gear durability, torsional strength, and motion noise tests. The use of FRP materials offers significant potential to realize lightweight components; however, certain challenges related to their properties that may limit their application must be addressed on a case-by-case basis.

Effect of Vanadium on the Microstructure and Mechanical Properties of 2100 MPa Ultra-High Strength High Plasticity Spring Steel Processed by a Novel Online Rapid-Induction Heat Treatment

Advanced automotive industries generate large demand for the next generation of high strength and high toughness spring steels. Vanadium-containing 55SiCrV spring steels subjected to rapid-induction heating treatment can fulfil such requirements. However, the effect of vanadium microalloying under online rapid-induction heat treatments is rarely reported. A comparative study of the microstructure and tensile properties of 55SiCr and 55SiCrV spring steel wires subjected to a novel online rapid induction heat treatment has been demonstrated herein. It is found that the tensile strength of the 55SiCr spring wire decreases with the decrease in the wire speed in online rapid-induction heating, and the plasticity increases. Whereas, the tensile strength of the 55SiCrV steel wire increases with the decrease in the wire speed with the retained high plasticity, which is attributed to the strengthening effect of the dislocations. Through the optimized rapid-induction heating/cooling thermal cycles and intermediate-temperature tempering treatment, the tensile strength of the 55SiCrV steel wire approaches 2106 MPa with total elongation of 9.7%. Compared with the 55SiCr spring steel, the addition of V in 55SiCrV spring steel changes the strengthening and toughening mechanisms via the grain refinement and enhancement in the hardenability and tempering resistance. The finely dispersed V-containing secondary phases are rarely found in the matrix, which indicates that the precipitation effect stemming from the addition of V is not the dominant strengthening factor in the online rapid-induction heat process. The proposed novel online rapid-induction heat treatment provides a promising pathway for the mechanical property improvement of the spring steel.Graphical

Improving Electroactivity of N-Doped Graphene Derivatives with Electrical Induction Heating.

Graphene derivatives doped with nitrogen have already been identified as active non-noble metal materials for oxygen reduction reaction (ORR) in PEM and alkaline fuel cells. However, an efficient and scalable method to prepare active, stable, and high-surface-area non-noble metal catalysts remains a challenge. Therefore, an efficient, potentially scalable strategy to improve the specific surface area of N-doped graphene derivatives needs to be developed. Here, we report a novel, rapid, and scalable electrical induction heating method for the preparation of N-doped heat-treated graphene oxide derivatives (N-htGOD) with a high specific surface area. The application of the induction heating method has been shown to shorten the reaction time and improve the energy efficiency of the process. The materials synthesized by induction heating exhibited very high specific surface area and showed improved ORR activity compared to the conventional synthesis method. Moreover, we demonstrated that the temperature program of induction heating could fine-tune the concentration of nitrogen functionalities. In particular, the graphitic-N configuration increases with increasing final temperature, in parallel with the increasing ORR activity. The presented results will contribute to the understanding and development of nonmetal N-htGOD for energy storage and conversion applications.

Post-Processing of Cold Sprayed CoNiCrAlY Coatings on Inconel 718 by Rapid Induction Heating

Cold spray is a solid-state additive manufacturing process that has been increasingly used for restoration of damaged parts. Due to the nature of powder solid-state bonding, cold spray coatings usually possess pores in the microstructures. Heat treatment has been widely used as a post-processing method to reduce the porosity of cold sprayed coatings. However, it usually requires the whole component to be treated in the furnace and typically takes a few hours to finish the treatment. This study aims to develop a localized and rapid post-processing method for cold sprayed coatings. Multi-layer cold sprayed coatings of CoNiCrAlY on an Inconel 718 substrate were produced. Then the coatings were heat treated at 800 °C, 900 °C, 1000 °C and 1100 °C by rapid induction heating. The porosity level of the coatings reduced significantly after induction heating for a short period of merely 10 min. This is attributed to the preferential Joule heating at pore regions, which results in pore closures within the coatings. The potential application of induction heating as a rapid post-processing method for cold spray coatings has been demonstrated in this work.

An Inverse Analysis Method Applied to Optimization of Specimen’s Shape for Performing Hot Rapid Crushing Tests from Homogeneous Initial Temperature Field

Specific experimental tests with loadings conditions close to those of industrial fast forming processes as rapid forging, rapid stamping or high speed machining, characterized by large plastic strains, localized deformations and important gradients of strain rates, strain and temperature, requires to analyses material flow behavior at different initial temperatures. One of the more important conditions to obtain intrinsic rheological constitutive equations is to have a quasi-homogenous initial temperature distribution and especially to keep constant the material microstructure during the specimens heating. The rapid induction heating seems to be one of the most reliable processes. This scientific study proposes an inverse analysis technique based on numerical finite element modelling to define on the thermal point of view, optimal specimen shapes for performing hot rapid crushing tests from homogenous initial temperature field.

A smart magnetically separable MIL-53(Al) MOF-coated nano-adsorbent for antibiotic pollutant removal with rapid and non-contact inductive heat regeneration

Metal-organic framework (MOF), MIL-53(Al), coated magnetic nanoparticles (MNP) were developed in this work for highly efficient adsorption and removal of an antibiotic pollutant oxytetracycline (OTC) from water. The adsorbed OTC molecules, which are heat labile, can be degraded rapidly using inductive heating which also regenerates the nano-adsorbent. Polyethylene glycol (PEG) coated MNP was used as a seed for growing the MIL-53(Al) MOF. The MIL-53(Al) coating was achieved via a facile green synthesis route using deprotonated terephthalic acid in an aqueous alkaline solution. The MIL-53(Al) coating layer on the MNP was found to have low crystallinity compared to that of the pristine MIL-53(Al) possibly due to the mismatch growth on the PEG-coated MNP surface. Nevertheless, the obtained nano-sorbent displays high OTC adsorption capacity of 794 mg/g at optimal pH 8. The adsorbed OTC on the nano-sorbent can be destructed using a rapid non-contact inductive heating of the magnetic core. Adsorption and regeneration were carried out up to 9 cycles in the presence of OTC. FTIR and PXRD shows that OTC adheres strongly to the MIL-53(Al) framework which causes gradual MIL-53(Al) degradation after several cycles of heat regeneration. Nevertheless, the MIL-53(Al) coated MNP without the adsorbed OTC shows strong structural integrity even after 9 regeneration cycles. The work demonstrates the high potential of the developed nano-sorbent for use in pollutant removal, magnetic separation of toxic pollutants as well as rapid regeneration of the nano-sorbents using induction heating.

Induction Heating of Gear Wheels in Consecutive Contour Hardening Process

Induction contour hardening of gear wheels belongs to effective heat treatment technologies especially recommended for high-tech applications in machinery, automotive and aerospace industries. In comparison with long term, energy consuming conventional heat treatment (carburizing and consequent quenching), its main positive features are characterized by high total efficiency, short duration and relatively low energy consumption. However, modeling of the process is relatively complicated. The numerical model should contain both multi-physic and non-linear formulation of the problem. The paper concentrates on the modeling of rapid induction heating being the first stage of the contour induction hardening process which is the time consuming part of the computations. It is taken into consideration that critical temperatures and consequently the hardening temperature are dependent on the velocity of the induction heating. Numerical modeling of coupled non-linear electromagnetic and temperature fields are shortly presented. Investigations are provided for gear wheels made of a special quality steel AISI 300M. In order to evaluate the accuracy of the proposed approach, exemplary computations of the full induction contour hardening process are provided. The exemplary results are compared with the measurements and a satisfactory accordance between them is achieved.

A novel active braze composition design route for C/C composite using Fe as active element

A novel active braze composition design route for carbon fiber reinforced carbon composite (C/C) using weak carbide former of Fe as active element based on Fe-C eutectic reaction was firstly proposed and demonstrated to increase service temperature of brazed C/C joint. Five kinds of commercial Fe-based sheets, including commercially pure iron (CPFe), mild steel, Invar alloy (4J36), stainless steels (SS) 304 and 630, were used as braze to investigate wettability. Brazing was performed by rapid induction heating in flowing argon at 1250 °C for 5 min under 0.5 MPa. C/C composite and each braze were dissolved well by Fe-C eutectic reaction, forming (i) intimate interface without gap defect, and (ii) dense bond seam consisting of retained austenite with high carbon content (∼35 at.%) without (only for SS) or with pro-eutectic carbides. CPFe showed the maximum penetration depth in C/C composite up to 25 μm, while 630SS exhibited the smallest contact angle (20–45°) and detectable interfacial carbide, resulting in a shear strength of 16 ± 1 MPa. The results demonstrated that Fe is a promising active element for C/C composite with cheap, rapid, robust, and high remelting temperature attractive features.

Tunable electromagnetic wave absorbing properties of carbon nanotubes/carbon fiber composites synthesized directly and rapidly via an innovative induction heating technique

Carbon nanotubes (CNTs) can create a larger specific surface area and space conductive network with its in-situ growth on the carbon fiber (CF) felt, which have the potential to be an excellent electromagnetic (EM) wave absorbing materials. Herein, we reported a fast and effective induction heating method to in-situ grow CNTs on the CF matrix to prepare carbon nanotubes/carbon fiber (CNTs/CF) composites. The CNTs/CF composites prepared by rapid induction heating have light weight and excellent flexibility. Due to the dense space conductive network formed by CNTs, the EM wave absorbing properties of CNTs/CF composite features 1% filling amount, thin absorption thickness, and width absorption bandwidth. The minimum reflection loss (RL) and peak location can be tailored by controlling the dopant ratio of ferrocene, range from −44.46 dB at 14.16 GHz (the effective bandwidth below −10 dB was achieved in a wide range from 10.48 to 17.92 GHz at the thickness of 3 mm) to −40.615 dB at 5.36 GHz (the bandwidth below −10 dB is narrowed from 4.80 to 6.24 GHz at the thickness of 4.7 mm). Due to its extremely light weight, excellent EM wave absorbing property and flexibility, CNTs/CF composites have the potential to be used in the chip-shielding field. • The innovative induction heating was proposed to prepare CNTs/CF composite. • EM wave absorption performance can be controlled by adjusting the density of CNTs. • The excellent EM wave absorption performance can be obtained with a filling amount about 1%. • The EM wave loss mechanism is discussed in detail.

Fatigue Properties of Quenching and Tempering Steel Using Super Rapid Induction Heating

Fatigue Properties of Quenching and Tempering Steel Using Super Rapid Induction Heating

Effect of Oxide Scale on Hot Dip Zn-Al-Mg Alloy Coating Prepared by Reduction Combined with Induction Heating

Hot dipping Zn-Al-Mg coatings were prepared by rapid induction heating combined with gas protection. The influence of oxide scale on the structure and surface quality of a hot-dip Zn-6Al-3Mg alloy coating was studied in this paper. The results showed that the reaction of Fe-Al was suppressed by the scale on the surface of the steel plate. When the thickness of scale was 10 μm and the steel entry temperature was 900 °C, the surface quality of the coating was good. The Zn-Al-Mg coatings mainly consisted of the ternary eutectic structure of Zn/Al/MgZn2 and Fe4Al13 at the interface. When the scale thickness was 2–3 μm with the same steel entry temperature, the surface quality of the coating was poor, and serious stripe-like protrusion defects were formed on the surface of the coating, which was mainly caused by the Fe4Al13 phase separating from the substrate / coating interface into the overlay.

Size-Controlled Synthesis of Iron and Iron Oxide Nanoparticles by the Rapid Inductive Heating Method.

Inductive heating synthesis is an emerging technique with the potential to displace the hot-injection synthesis method to prepare colloidal particles very rapidly with a narrow size distribution, controlled size, and high crystallinity. In this work, the inductive heating synthesis is applied to produce a short-temperature jump to mimic conditions like the hot-injection method to prepare traditional iron and iron oxide nanoparticles (IONPs) in the 3–11 nm size range within various solvents, precursors, and reaction time conditions. Moreover, this inductive heating technique can be used under unique experimental conditions not available for hot-injection reactions. These conditions include the use of very high initial monomer concentrations. Considering benefits over conventional methods, the inductive heating technique has the potential to provide an industrial level scale-up synthesis. The magnetization of these particles is consistent with the magnetization of the particles from the literature.

Application of Electrochemical Noise to Investigate Role of Microstructural Evolution on Inhibiting Stress Corrosion Cracking of Ti–6Al–4V Weldment

Using the electrochemical noise method, this paper studies the effect of microstructure of weld seam on the stress corrosion cracking behavior of Ti–6Al–4V alloy weldment. Local rapid induction heating can significantly change the microstructure, and the acicular α′ martensite phase in the weld seam is decomposed into lathy α phase and transformed β phase. The higher heat temperature leads to more transformed β phase and less lathy α phase. The mechanical properties and stress corrosion cracking sensitivity during the slow strain rate tensile test are significantly affected by the microstructure of weld seam, which are improved with the decomposition of acicular α′ martensite and decrease of lathy α phase content combined with increase of transformed β phase content. Compared with the non-treated sample, the induction heating enhances the corrosion resistance of the sample and delays the occurrence time of localized corrosion during the slow strain rate tensile test. The higher corrosion resistance and the later occurrence time of localized corrosion are caused by the higher induction heating temperature. The microstructural evolution of the weldment significantly inhibits the stress corrosion cracking process.

MoSi2-based cylindrical susceptor for rapid high-temperature induction heating in air

Abstract Conductive susceptors are necessary for heating non-conductive materials in induction heating systems. Susceptor materials should have sufficient electrical conductivity and thermal/chemical stability under a range of environmental conditions. However, many susceptor materials oxidize in high-temperature environments, resulting in degradation and poor durability. Here, we used intermetallic MoSi2 ceramics as a susceptor material and designed a cylindrical susceptor to apply to rapid high-temperature induction heating in an oxidizing environment. MoSi2 was prepared by self-propagating high-temperature synthesis (SHS), and then used to fabricate cylindrical susceptors by slip casting. The optimal thickness of the susceptor was controlled by modelling. A MoSi2-based cylindrical susceptor with SiO2 protective layer showed higher heating rate (4.2–26.8 °C/s at 0.5–2.5 kW) than a commercial rod-type susceptor (7.7–13.6 °C/s at 1.0–2.5 kW) of the same material. In addition, our susceptor endured high temperatures below 1700 °C and severe thermal cycle (700–1600 °C, heating for 2min and cooling for 1min) during 36 cycles. In general, these results demonstrate that the MoSi2-based susceptor can be applied to a rapid induction heating furnace that can be used in air at a high temperature of 1600 °C (equal to the available temperature of a commercial graphite susceptor in H2).

Effects of Rapid Induction Heating on Transformations in 0.6% C Steels

Rapid induction surface hardening of high-carbon steel with an initial martensitic microstructure can attain the very high-strength levels needed for lightweighting components such as shafts, gears, and bearings that are subjected to high operating stresses. Specimens of pearlitic and martensitic 0.6 wt pct C steels were heat-treated using a dilatometer to investigate the effects of prior microstructure, heating rates (5 to 500 °C/s), and austenitizing temperatures (850 to 1050 °C) on the transformation to austenite and subsequent transformation to martensite during helium quenching. Specimens were quenched from selected temperatures during heating to assess the initial cementite precipitates formed in martensite before transformation to austenite. Other specimens were isothermally held at the austenitizing temperature to assess cementite dissolution rates and austenite grain evolution. Higher heating rates increased the Ac1 and Ac3 temperatures and lowered the Ms temperatures. Martensitic prior microstructures resulted in lower Ms temperatures and lower hardness as compared to a pearlitic prior microstructure. Alloy content and the austenitizing temperature (900 or 1150 °C) utilized to provide the initial martensitic microstructure also influenced the transformation temperatures and the amount of retained austenite.