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Herein, laboratory experiments are conducted to evaluate the effect of sulfur and lanthanum content in the steel on the modification of inclusions. The amount, composition, morphology, and size of nonmetallic inclusions in the steel are observed using an automatic scanning electron microscope. Results show that as the lanthanum content in the steel increased from 0 to 72 ppm, the inclusions in the steel with 12 ppm sulfur are modified in the following order: Al2O3–CaO–MgO → LaAlO3 → LaAlO3–La2O2S → La2O2S. Similarly, when the sulfur content is 27 ppm, inclusions transformed in the order of Al2O3–CaO–MgO → LaAlO3 → LaAlO3–La2O2S → La2O2S → La2O2S–LaxS → LaxS as the lanthanum content increases from 0 to 150 ppm. Thermodynamic analysis using FactSage based on a private database is employed to reveal the mechanism for the modification of inclusions. Additionally, a kinetic model is established to study the transformation rate of inclusions in the steel after the addition of lanthanum and sulfur. Liquid Al2O3–CaO–MgO inclusions disappear after 800 s when the steel contains 12 ppm sulfur and 12 ppm lanthanum. The composition of inclusions is 53%LaAlO3–47%La2O2S at 1800 s, while it is 100%La2O2S and 80%La2O2S–18%LaxS–2%CaS when the lanthanum content is 33 and 72 ppm, respectively. [ABSTRACT FROM AUTHOR]

The objective of this work is to study the ability of friction surfacing to deposit metal alloys that are difficult to process with traditional methods. Creep and neutron irradiation-resistant oxide dispersion strengthened (ODS) materials cannot be produced via the conventional casting route due to the insolubility of the oxidic and metallic alloy constituents, causing unintended inhomogeneous oxide dispersion and material behavior. Increasing the silicon content of iron-silicon (Fe-Si) improves electromagnetic properties but embrittles the material significantly, and fusion-based manufacturing methods are unable to process this steel. The solid-state nature of the friction surfacing process offers a potential alternative processing route to enable wider usage of difficult-to-process alloy systems. Both ODS and Fe-Si materials are available in powder forms. While the existing literature in friction surfacing focuses on depositing composites by incorporating small quantities of powders through holes in consumable rods, this is the first study showing that a large charge of powder can be converted to a homogeneous fully consolidated deposit in friction surfacing. A novel methodology is used that incorporates the high portion of powder feedstock into hollow consumable friction surfacing rods (up to 35% volume fraction). It was found that fully consolidated deposits can be produced with powder feedstocks using the proposed methodology. A recrystallized, homogeneous, equiaxed microstructure was observed in Fe-Si 6.8 wt% and a new-generation FeAlOY ODS alloy deposits processed with hollow stainless steel friction surfacing rods. Both powder and rod material plasticize and deposit without bulk intermixing. [ABSTRACT FROM AUTHOR]

To improve the cleanliness of oriented silicon steel, industrial experiments are performed under different refining slag composition conditions. The results show that the use of medium‐basicity refining slag (w(CaO)/w(SiO2) = 2.3–2.6, w(CaO)/w(Al2O3) = 2.3–2.6) results in higher steel cleanliness with lower Al2O3 volume fraction, and smaller inclusions. In addition, the thermodynamic equilibrium between the oriented silicon steel slag and the molten steel is investigated at a temperature of 1873 K (1600 °C) to understand the effect of different slag compositions on the oxygen content and Al2O3 absorption capacity. Furthermore, a mathematical model is introduced to describe the behavior of inclusions at the steel–slag interface as well as to predict the removal of oxide inclusions during the slag‐refining process. The experimental and predicted results for inclusion removal after slag refining are in good agreement. [ABSTRACT FROM AUTHOR]

AbstractThe present study concentrates on the development of carbide-free bainite steel and explores its tribological and mechanical characteristics using a newly devised disk-on-disk tribometer. The microstructure of the treated samples was examined through heat treatment at various holding temperatures (300, 350, and 400 °C) and durations (10, 20, and 30 min), along with isothermal transformation. The wear rate demonstrated significant sensitivity to holding duration, transformation temperature, phase fraction, and the stability of retained austenite. The microstructural analysis encompassed atomic force microscopy (AFM), FE-SEM, x-ray diffraction (XRD), and energy-dispersive x-ray spectroscopy (EDS). The study extensively investigated the robust correlation among mechanical properties, microstructure, wear behavior, and the presence of retained austenite (RA) and bainite volume fraction. The findings indicate that carbide-free bainite steel holds promise for replacing conventional railway wheel track steel in the steel industry. The structural property correlations have developed of high silicon steel, hardness reduced with increasing temperature and isothermal preserving time; resulting in a gradual increase in the wear rate of CFB steel. The salt bath soaking temperature of 350 °C with a period of 30 min was found to be the preeminent wear properties condition for CBF steel. [ABSTRACT FROM AUTHOR]

With the rise of eco-friendly policies, advanced motor technologies are being developed to replace fossil fuel-based engines in the mobility industry. Axial flux motors, known for their ability to reduce size and increase output torque compared to radial flux motors, require different materials and manufacturing techniques. Specifically, the production of complex stator cores and segmented magnets presents significant challenges, often leading to higher costs. To address this issue, soft magnetic composite (SMC) materials, which offer greater design flexibility, are being explored for use in stator cores. However, soft magnetic composite materials exhibit lower permeability and saturation flux density compared to laminated silicon steel, resulting in reduced output torque and efficiency. This paper investigates the effects of stator geometry on axial flux motor performance and explores cladding core technology, which combines soft magnetic composite materials with silicon steel. By conducting finite element method (FEM) analysis to evaluate the output torque and efficiency based on the shape of the silicon steel within the cladding core, this study proposes an optimized cladding core design to enhance the efficiency and output torque of axial flux motors. [ABSTRACT FROM AUTHOR]

In this paper, Fe-3%Si ultra-thin ribbons prepared by the planar flow casting (PFC) technique were subjected to temper rolling and annealing treatments. The microstructure and texture evolution during this process were examined through experimental measurements coupled with crystal plasticity finite element (CPFE) simulation to assess the feasibility of preparing ultra-thin non-oriented silicon steel using PFC ribbons. The results indicate that the PFC ribbons exhibit a significant columnar crystal structure, and {001}-oriented grains comprise over 30%. After being annealed, the grains with different orientations grew uniformly, the texture components were basically unchanged, and the {001} texture was well preserved. When annealing was carried out after temper rolling with a reduction rate of 7%, uneven grain growth was observed, and the growth tendency of the {001} grains, especially, surpassed that of the {111} grains, with an elevated temperature which peaked at 950 °C, where the proportion of {001} grains was maximal. When being annealed after temper rolling to 15%, grains of other orientations showed significant growth at each temperature, while the {001} grains did not show an obvious growth advantage. Utilizing the CPFE, the deformation-stored energy distribution of each characteristic-oriented grain was simulated, and it was shown that compared to the 15% rolling reduction rate, the deformation-stored energy accumulation of {001}-oriented grains after being rolled to 7% reduction was significantly lower than that of {111}-oriented grains. It suggests that the larger stored energy difference makes {001} grains show a stronger growth advantage based on the SIBM mechanism during annealing, after being rolled with a reduction rate of 7%. Overall, for the synergistic optimization of microstructure and texture, rolling with a 7% reduction rate followed by annealing at 950 °C in a hydrogen atmosphere is most advantageous. [ABSTRACT FROM AUTHOR]

To investigate the impact of diverse multivariate mixing excitation conditions on the hysteresis loop of ferromagnetic materials, this study initially constructs a magnetic performance testing system for electrical steel. This system is capable of generating mixed excitation utilizing a standard Epstein square‐circle setup. Subsequently, the study measures the magnetic properties of the oriented silicon steel sheets at various mixing AC frequencies of the hysteresis loop data. Secondly, a hybrid network model integrating a convolutional neural network (CNN) and a bi‐directional long short‐term memory network (BiGRU), augmented with an attention mechanism (AM), is proposed and utilized for predicting the hysteresis properties of oriented silicon steel wafers subjected to compound mixed‐frequency excitation. The model utilizes CNN to extract high‐dimensional data features reflecting the hysteresis characteristics of the loop, BiGRU to capture the temporal evolution patterns of the key feature vectors, an AM to weigh the feature parameters and emphasize the key features, and a Bayesian optimization (BO) algorithm based on neural network hyperparameters for automatic selection, enhancing prediction accuracy. In comparison with experimental observations, the method accurately predicts material hysteresis properties under non‐sinusoidal complex excitation conditions, outperforming existing deep‐learning network models. © 2024 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Magnetic flux leakage from the rotor core bridge must be improved in interior permanent magnet motors to improve their performance. The partial non-magnetization of bridges is effective in reducing magnetic flux leakage. In our previous studies, we proposed a new partial nonmagnetization process for silicon steel, which was used for the rotor core. The portion of the silicon steel sheets that becomes a bridge after pressing can be non-magnetized by melting and mixing Ni-Cr-B alloy powder with the silicon steel sheets using a laser beam and then laminated to produce the rotor core. In this study, the effect of B addition to Ni-Cr alloy powder was widely investigated to optimize the B addition amount. Based on the appearance, solidification defect, and magnetic and mechanical strength properties of the improved portion, the optimal content of B was within the range of 0.5-1.0 mass%. Furthermore, core sheet samples with an improved portion, which had the improved length of 1.0mm and has the composition of Fe-13.9 mass%Cr-15.1 mass%Ni-2.3 mass%Si-0.5 mass%B, were prepared by laser and press processing. A rotor core was fabricated using core sheets and evaluated for its magnetic flux and high-speed rotation for practical use. The prototype rotor core exhibited a 32% higher magnetic force and could rotate at speeds of up to 43,000 rotations. It is expected that the size of interior permanent magnet motors will be reduced due to the increased magnetic force. [ABSTRACT FROM AUTHOR]

In the process of hot rolling silicon steel, roll wear directly affect its shape. Accurate prediction of roll wear is an important condition for rolling qualified silicon steel strips. The traditional roll wear prediction model is established by the slicing method. The wear of F5–F7 work rolls used for finishing rolling silicon steel on a 2250 mm production line in a steel mill was predicted by this model. It was found that there was deviation between the predicted results and the actual wear, and the prediction accuracy of the model was insufficient. Therefore, the wear of the surfaces of the rolls used for rolling silicon steel on this production line was studied. Based on the analysis of the work roll wear's form and the rolling parameters that affect the roll wear, the traditional roll wear prediction model was optimized by the genetic algorithm. Finally, the optimized model was verified, and the prediction accuracy of the wear prediction model improved. The accurate prediction results provide a basis for the formulation of a shape control strategy when rolling silicon steel on this production line. [ABSTRACT FROM AUTHOR]

In order to study the texture evolution and the formation of an inhomogeneous microstructure in hot-rolled plate of grain-orientated silicon steel, Fe3C (hexagonal) and ferrite phases in the subsurface layer were studied using electron backscatter diffraction. The results indicate that fiber texture (ferrite) mainly composed of {441}<104> and (110)[001] Goss oriented grains was formed at a depth of 25% of the thickness of hot-rolled plate. Matrix grains in the subsurface layer were arbitrary separated into irregular large grains (≥40 μm) and fine grains (<40 μm), and the grain boundary characteristics and texture evolution of matrix grains were studied. The results indicated that the formation of the colonies of fine grains was the result of dynamic recrystallization, and high-frequency low-misorientation-angle boundaries (0~20°) were formed between large grains (≥40 μm) and fine grains (<40 μm), which can be considered as the irregularity of large grains caused by solid-state wetting. Due to the texture evolution of large grains (≥40 μm), a large number of high-energy boundaries (20~45°) were formed between irregular large grains (≥40 μm), resulting in rapid consumption between adjacent large grains and the elongation of large grains along the rolling direction. Therefore, it can be assumed that the migration of low-misorientation-angle boundaries (0~20°) under solid-state wetting and high-energy boundaries (20~45°) are important mechanisms for non-uniform grain growth in hot-rolled plate of grain-orientated silicon steel. [ABSTRACT FROM AUTHOR]

An excellent Fe-3.3 wt% Si steel was fabricated by double cold rolling and final annealing. The evolution of the microstructure and texture was studied by optical microscope (OM), X-ray diffraction (XRD), ex situ, and quasi-in situ electron backscattered diffraction (EBSD) to investigate the recrystallization behavior. Double cold rolling significantly reduced the adverse γ texture in the final annealed sheets, and a stronger η texture was observed. With a reduction ratio of 50% and 65% during double cold rolling, the γ texture almost disappeared, whereas the η texture was obviously improved. Consequently, the texture factor reached its peak, leading to a reduction in iron loss and an enhancement of magnetic induction. By combining texture regulation with dislocation strengthening, the magnetic properties of Fe-3.3 wt% Si steel were improved, and the yield strength also increased. The final sheet exhibiting exceptional magnetic characteristics and enhanced strength attained a reduction in iron loss (P10/400 = 21.84 W/kg) of 6.43 W/kg, along with an enhancement of magnetic induction (B50 = 1.698 T) of 0.038 T and yield strength (Rp0.2 = 578 MPa) of 37 MPa compared to a single-stage cold rolling process. [ABSTRACT FROM AUTHOR]

The effects of cold rolling reduction on the microstructure, recrystallization behavior, and magnetic properties of 3.0%Si-0.8%Al-0.3%Mn steel were studied by X-ray diffraction (XRD) and electron backscatter diffraction (EBSD). With the reduction rates of 78%, 85% and 87% in the cold rolled sheet, the width of the deformation band becomes narrower, the number of intragranular shear bands decreases, and the proportion of grain boundaries increases. The intensity of the α and γ fibers texture in the cold rolled sheet is enhanced, and the annealed sheet is dominated by the γ fibers texture and the content increases from 26.0% to 34.5%. During the recrystallization process, the Goss and γ-grains nucleate first. The λ-grains nucleate mainly at the grain boundaries of the deformed α-grains, and the α-grains ultimately recrystallize. With the increase in the cold rolling reduction rate, the γ-grains develop into the main texture due to a large amount of nucleation at the deformation band and grain boundary. The λ-grains with a high mobility do not have a numerical advantage, and the increase in the texture content is very small. The content of the unfavorable γ fiber texture in the annealed sheet increases, the magnetic induction intensity B50 decreases, Pe and Pt decrease significantly, and the critical grain size with the lowest iron loss decreases from 136.2 to 109.4 μm. [ABSTRACT FROM AUTHOR]

Density, surface tension, and viscosity of various liquid electrical steels are measured at different temperatures, varying in their silicon content between 3 and 6 mass%. Density and surface tension are determined using the maximum bubble pressure method, while viscosity is investigated comparatively using a vibrating finger viscometer and an oscillating crucible viscometer. The results are compared with models known from the literature. Based on this, the density of the steel [ρ] = kg m−3 and the surface tension [σ] = N m−1 can be described as a function of temperature [θ] = °C and silicon content [Si] = mass% using the equations: ρ(θ,Si)=−1.28×θ−104.18×Si+9081.8, σ(θ,Si)=10−4×[ −0.00903×θ2−1.21494×Si2+29.268×θ−1.987×Si−22334 ]. There is a lack of experimental data in the literature for high‐temperature thermophysical properties for electrical steels. This underlines once again the novelty and significance of this study, as the determined thermophysical properties are essential for a wide range of applications. For instance, they are crucial in the production of metallic powders for additive manufacturing by atomization to adjust the properties of the powders precisely. The findings are also important for steelmaking itself, as the corrosion behavior of refractory material can be better determined. [ABSTRACT FROM AUTHOR]

The microstructural and textural evolution, as well as the recrystallization kinetics under different cold‐rolling methods and their influencing mechanism on the properties of the thin‐gauge 3.5%Si nonoriented silicon steel, are investigated by electron backscattering diffraction, X‐ray diffractometer, tensile, and magnetic properties test. The results indicate that compared with the primary cold‐rolling process, the reduction rate of secondary cold‐rolling process is lower (58.3%), and many shear bands are formed in the coarse cold‐rolled sheet, which leads to the formation of strong Goss and cube texture after recrystallization annealing. Owing to the high annealing temperature, the average grain size of finished annealed sheet is little different under different cold‐rolling processes, so the mechanical properties and high‐frequency iron loss are basically the same. The iron loss of the secondary cold‐rolled products decreases with an increase in frequency, and the improvement in the iron loss of the high field (1.5 T) becomes larger than that of the low field (1.0 T). Given the high anisotropy index of the Goss texture, the iron loss anisotropy of the secondary cold‐rolled sheet is higher. Considering the magnetic and mechanical properties, the optimum process is the secondary cold rolling with the intermediate annealing temperature of 900 °C. [ABSTRACT FROM AUTHOR]

With the introduction of China's "Carbon Peaking Action Plan Before 2030," the transformation of the power industry has released huge opportunities and potential. The DC distribution network can well-coordinate the contradiction between distributed power and grid access, fully develop the benefits of distributed energy, and become a new direction for the development of the power industry. However, the current traditional DC-DC converters have problems such as single-topology structure and low power density, which can only complete one-way transmission of energy; hence, the distributed energy cannot be fully utilized. Addressing the problem of distributed energy transfer, this paper is based on a three-port DC-DC converter for a low-voltage DC distribution network to realize energy transfer between the DC distribution network, distributed energy, and low-voltage load. First, the energy transfer modes of the three-port DC-DC converter are introduced. Combined with the converter topology and energy transfer mode, a simplified equivalent model of the converter is established. The voltage gain characteristics and frequency characteristics of this converter are studied. Furthermore, the effects of the excitation inductance to primary resonance inductance ratio parameter k and quality factor Q on the voltage gain characteristics of the converter are discussed. On this basis, the resonant cavity design of the converter is based on the optimal selection of parameters k and Q so that the converter can meet the voltage gain requirements in both forward and reverse operations. The simulation results under different loads verify the reasonableness of the resonant cavity component selection. [ABSTRACT FROM AUTHOR]

The dynamic behavior of nonmetallic inclusions at the bubble–steel interface is a key factor contributing to the formation of large‐sized inclusions or clustered particles and is particularly important for the production of high‐quality‐oriented silicon steel. In this study, high‐temperature confocal laser scanning microscopy is employed for in situ observation of the agglomeration behavior of Al2O3 inclusions of varying sizes. The critical distance of attraction decreases with the decrease in inclusion size. The effects of particle size, distance, surface tension, density, and different types of inclusions on the capillary force are explored in detail using the Kralchevsky–Paunov model. In the model results, it is highlighted that the degree of influence among the factors affecting the capillary force decreases in the following order: contact angle > size > distance > density > surface tension. Furthermore, the observed results are compared with the model calculation results. The trends of the model calculations and the experimental results show good agreement, but most of the experimental values are higher than the theoretical values. The errors primarily stem from inclusion shape, interference from other inclusion forces, and interactions between the crucible wall and inclusions. [ABSTRACT FROM AUTHOR]

Industrially, the silicon requirement of liquid steel is often met with ferrosilicon (FeSi) instead of high‐purity silicon addition. FeSi, a silicon‐rich alloy, contains impurities typically inherited from its manufacturing stage. Therefore, FeSi addition results in the formation of complex inclusions in the liquid steel. Herein, a detailed inclusion characterization of the samples obtained from the melting experiments for a wide range of silicon concentrations has been carried out to examine the effect of FeSi impurities. Pure silica inclusions evolve to silica‐ and/or alumina‐based Si–Al–(Ti)–O–(TiN) complex inclusions with the increasing addition of FeSi to the steel melt. Reduction of silica by aluminum or titanium, the presence of titanium in the steel melt, and/or TiN inclusions formed at the periphery of oxide inclusions restrict the growth of oxide inclusions, resulting in small‐sized (average) oxide inclusions. The underlying mechanism of such complex (Si–Al–Ti–O–N)‐based inclusions has been explained with the aid of microstructural characterization and thermodynamic calculations. Moreover, the steel–crucible (alumina) interface has also been investigated for inclusion deposits and crucible–steel interaction. [ABSTRACT FROM AUTHOR]

Texture control, which is affected by composition, hot rolling, cold rolling, and annealing, is the core element to improve the magnetic properties of grain-oriented silicon steel and is one of the key scientific problems in developing electrical steel technology. The research and control of first factors have been very mature, and the integrated regulation of upstream and downstream processes has become a breakthrough point for improving texture. For the common grain-oriented silicon steel based on the "two-stage cold rolling method", primary recrystallization is the stage achievement of smelting, hot rolling, first cold rolling, and decarburization annealing. The grain size and texture characteristics of the primary recrystallization are the only standards to measure the pre-process technology and is the pointer of whether the secondary recrystallization can occur in the subsequent process or not, which are extremely important to improve the magnetic properties. This paper studied the hot rolling, the first cold rolling and decarburization annealing of grain-oriented silicon steel by using XRD, EBSD technologies. The results showed that the hot rolled plate is not as thinner as better, only the optimum ratio of the thickness of hot rolled plate and the first cold reduction rate can obtain optimal primary recrystallization. The minimum iron loss value and maximum magnetic induction intensity are obtained under the primary cold rolling reduction rate controlled at 77.27%, the average grain size of the primary recrystallization is 14 µm, the iron loss P1.7/50 is reduced to 1.02 W/Kg, and the magnetic induction intensity B8 can reach 1.910 T. [ABSTRACT FROM AUTHOR]

Effects of Sn on microstructure, texture and magnetic properties of 2.7%Si-0.5%Al non-oriented silicon steel in industrial production were studied by X-ray diffraction and electron backscattering diffraction. Furthermore, combining first-principles simulation with White–Coghlan model calculation, grain boundary segregation of Sn was also investigated. In Sn-0.05 steel, cold-rolled sheet showed more ingrain shear bands and intensity of textures weakened significantly. Addition of Sn obviously reduced intensity of {111}<112> and increased intensity of {114}<481>; strong {100}<120> and nearly Goss textures appeared in annealed sheet. P1.5/50 decreased by 0.05W/kg, B50 increased by 0.005 T, and stability of magnetic properties were obviously improved of Sn-0.05. In the unit grain boundary layer (1 Å−2), the excess solute concentration on the grain boundary layer of Sn corresponding to 20,000–30,000 appm was 0.16–0.22 and gradually decreased with temperature and increased with intragranular solute content. As a segregation element, during annealing process of hot-rolled band and cold-rolled sheet, Sn exerted a drag force on the grain boundaries, thus inhibiting the grain growth. {114}<481> and {100}<120> oriented grains could grow selectively and distribute evenly by virtue of their mobility and quantity advantage higher than {111}<112>, thus improving magnetic properties and stability of 2.7%Si-0.5%Al non-oriented silicon steel. [ABSTRACT FROM AUTHOR]

Copyright of Automobile Technology is the property of Automobile Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The use of low-carbon unalloyed steel with minimal silicon content is widespread in structural steel and automotive applications due to its ease of manipulation. The mechanical properties of this steel can be significantly enhanced through severe plastic deformation (SPD) techniques. Our study focuses on the practical benefits of the dual rolling equal channel extrusion (DRECE) method, which strengthens the steel and has implications for material hardness and the thickness of subsequently applied hot-dip zinc galvanizing. Furthermore, the steel's corrosion potential and current are investigated as a function of material hardness and thickness. The findings show a 20% increase in hardness HV 30 after the first run through the forming machine, with an additional 10% increase after the second run. Subsequent galvanizing leads to a further 1–12% increase in HV 30 value. Notably, the DRECE hardening demonstrates no statistically significant effect on the corrosion potential and current; however, the impact of galvanizing is as anticipated. [ABSTRACT FROM AUTHOR]

The cold-rolled non-oriented silicon steel sheets with a Si content of 2.4 wt.%, produced by continuous and reversible cold rolling, were used as the experimental material. The effects of annealing temperature on the microstructure, texture, and magnetic properties were studied by optical microscopy, an X-ray diffractometer, and a magnetic property measuring instrument. The experimental results showed that the dominant texture components at the surface of both sheets were almost the same, i.e., α and γ fibers. After annealing at 920 °C for 30 s, a complete recrystallization occurred in both sheets. When annealing below 1070 °C, the average grain sizes of continuous cold-rolled sheets were slightly higher than those of reversible cold-rolled ones. Additionally, for all specimens, the recrystallization texture components were γ fiber, as well as weak α fiber, λ fiber, and Goss texture. Additionally, the difference was the texture intensity. The iron losses of the finished products of continuous cold rolling were lower than those of the finished products of reversible cold rolling with the increase in annealing temperature, and the magnetic induction was higher than that of the finished products of reversible cold rolling. [ABSTRACT FROM AUTHOR]

Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Grinding is a manufacturing process that demands cutting fluids due to its great heat generation. However, those fluids are extremely harmful to human health and nature. The minimum quantity of lubrication (MQL) has been a studied alternative, but its application in grinding is still limited due to its low heat removal and wheel clogging. In this context, the present research investigated the performance of a wheel cleaning jet (WCJ) associated with the MQL (MQL + WCJ) at three flow rates in grinding of VP50IM steel with a black silicon carbide wheel, comparing the results with MQL and flood method. The evaluated output parameters were workpiece surface roughness, surface topography, roundness error, diametrical wheel wear, G ratio, grinding power, tangential cutting force, acoustic emission, grinding cost analyses, and CO2 pollution emission. The application of the wheel cleaning jet reduced up to 17% the surface roughness, 16% the roundness error, 18% the diametrical wheel wear, 17% the G ratio, 22% the grinding power, 23% the tangential cutting force, 20% the acoustic emission, 60% the manufacturing cost, and 68% the CO2 pollution emission. The application of WCJ improved the performance of the MQL technique and reinforced its potential to contribute to industrial-scale cleaner manufacturing. [ABSTRACT FROM AUTHOR]

Hot rolling is a critical thermomechanical processing step for nonoriented electrical steel (NOES) to achieve optimal mechanical and magnetic properties. Depending on the silicon and carbon contents, the electrical steel may or may not undergo austenite–ferrite phase transformation during hot rolling, which requires different process controls as the austenite and ferrite show different flow stresses at high temperatures. Herein, the high‐temperature flow behaviors of two nonoriented electrical steels with silicon contents of 1.3 and 3.2 wt% are investigated through hot compression tests. The hot deformation temperature is varied from 850 to 1050 °C, and the strain rate is differentiated from 0.01 to 1.0 s−1. The measured stress‐strain data are fitted using various constitutive models (combined with optimization techniques), namely, Johnson–Cook, modified Johnson–Cook, Zener–Hollomon, Hensel–Spittel, modified Hensel–Spittel, and modified Zerilli–Armstrong. The results are also compared with a model based on deep neural network (DNN). It is shown that the Hensel–Spittel model results in the smallest average absolute relative error among all the constitutive models, and the DNN model can perfectly track almost all the experimental flow stresses over the entire ranges of temperature, strain rate, and strain. [ABSTRACT FROM AUTHOR]

To examine the effect of mixed-frequency excitation conditions on the hysteresis and loss characteristics of ferromagnetic materials, this paper shows how to construct magnetic property test equipment for electrical steel using Epstein's square circle. Experiments were carried out to assess the hysteresis and loss properties of oriented silicon steel wafers under mixed-frequency sinusoidal operating conditions with different occupancy ratios. It used heterodyne extraction to investigate the effect of different occupancy ratios of industry and magnetization frequency on the hysteresis and loss characteristics of oriented silicon steel sheets. [ABSTRACT FROM AUTHOR]

This study aims to establish and optimize a process for the fabrication of 3D microstructures of the biocompatible polymer Parylene C using hot embossing techniques. The different process parameters such as embossing temperature, embossing force, demolding temperature and speed, and the usage of a release agent were optimized, utilizing adhesive micropillars as a use case. To enhance compatibility with conventional semiconductor fabrication techniques, hot embossing of Parylene C was adapted from conventional stainless steel substrates to silicon chip platforms. Furthermore, this adaptation included an investigation of the effects of the hot embossing process on metal layers embedded in the Parylene C, ensuring compatibility with the ultra-thin Parylene printed circuit board (PCB) demonstrated previously. To evaluate the produced microstructures, a combination of characterization methods was employed, including light microscopy (LM) and scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Fourier-transform infrared spectroscopy (FTIR). These methods provided comprehensive insights into the morphological, chemical, and structural properties of the embossed Parylene C. Considering the improved results compared to existing patterning techniques for Parylene C like plasma etching or laser ablation, the developed hot embossing approach yields a superior structural integrity, characterized by increased feature resolution and enhanced sidewall smoothness. These advancements render the method particularly suitable for diverse applications, including but not limited to, sensor optical components, adhesive interfaces for medical wearables, and microfluidic systems. [ABSTRACT FROM AUTHOR]

This study used the droplet solidification test and fast dip test to investigate the effects of boron on the interfacial heat transfer, contact behavior, naturally deposited film, and microstructure of 3.5 wt pct Si non-oriented silicon steel during sub-rapid solidification. The results showed that boron altered the surface tension of the molten steel, enhancing the interfacial wettability and heat transfer behavior between the steel and substrate. As the boron content increased from 0 to 97 ppm, the final contact angle decreased from 125 to 96 deg, while the maximum heat flux increased from 6.89 to 10.29 MW/m2, ultimately enhancing the surface quality of the cast strip. During the solidification of boron-containing silicon steel, boron volatilizes and combines with oxygen to form B2O3 on the substrate surface. It reduced the proportion of high melting point silicon oxides in the deposited film, decreasing its melting point. Furthermore, due to boron segregation and improved interfacial heat transfer, the average grain size of the cast strip decreased from 256 to 216 μm, accompanied by a more complex grain orientation. [ABSTRACT FROM AUTHOR]

0.3 mm‐thick grain‐oriented silicon steel sheets with varying Y contents are produced via twin‐roll strip‐casting and two‐stage cold rolling process. This study primarily investigates the evolution of microstructure, texture, and precipitation along the processing. Specifically, the effect of rare earth Y on second‐phase particle precipitation in ultralow carbon grain‐oriented silicon steel is examined. Results indicate that higher Y content will consume beneficial inhibitor elements such as S and N, leading to the formation of coarse rare earth inclusions (≈10 μm) in the cast strip. This significantly diminishes inhibition ability and magnetic induction (B8 = 1.58 T≈1.71 T). On the contrary, the addition of trace Y can accelerate the precipitation of inhibitors. During the intermediate annealing stage, steel with trace Y exhibits a significant enhancement in precipitate distribution density (from 2.8 μm−2 to 13.6 μm−2), and the final magnetic induction B8 increases from 1.86 T to 1.91 T compared to steel without Y. In addition, the results of first‐principle calculations based on density functional theory reveal that the doped Y atom prefers to segregate at the Al–N interface, and the interface energy reduces from 1.871 J m−2 to 1.024 J m−2, thereby promoting the precipitation of AlN. [ABSTRACT FROM AUTHOR]

This paper focuses on two models used for the determination of power loss components in steel samples under dynamic magnetizing conditions. The considered models differ in their approach as far as the possibility of distinguishing bulk and localized eddy currents is concerned. Two samples of non-oriented electrical steel differing in silicon weight contents are the subject of experiments. A comparison of the obtained results, as well as their discussion, is given in the paper. [ABSTRACT FROM AUTHOR]

Based on the experimental results, this study develops a multi-objective optimization scheme to obtain the set of optimal process parameters for pulsed laser direct cutting of non-oriented silicon steel sheets for manufacturing motor core laminations. The experiments were conducted in the nital solvent, which was the one with the smallest thermal effect of laser cutting among the candidate environments of air, deionized water, alcohol, lubricant oil, sodium chloride solution, and nital solution. The laser was a pulsed Nd:YAG nanosecond laser and the thickness of the silicon steel was 100 μm. The effects of three laser process parameters, laser power (P), cutting speed (v), and pulse repetition rate (f) on the cutting qualities of the heat-affected zone (HAZ), cutting time (TC), and multiple dimensional accuracies of the cut core lamination were examined. The inspected geometric accuracies included the errors in inner and outer core diameters (ED1 and ED2), the error in tooth width (EL), and the roundness of inner and outer diameters (C1 and C2). The developed multi-objective optimization model was a PSI-based ELM-GA scheme consisting of the extreme learning machine (ELM) model for connecting the inputs and the outputs, the preference selection index (PSI) method for obtaining the weighted multi-objective function, and the genetic algorithm (GA) for process optimization. Through employing the predicted optimal process parameter set, the validation experiment showed that the errors between the prediction and the experimental result for the seven qualities of HAZ, ED1, ED2, C1, C2, EL, and TC were 4.04%, 6.25%, 4.02%, 0.48%, 2.14%, 5.09%, and 1.25%, respectively. The HAZ and geometric accuracy of the cut core laminations were qualified for the subsequent lamination assembly. Consequently, the merit of direct formation of ready-for-assembly core laminations without the need for any post-processing renders the proposed laser cutting scheme an economical and effective approach for manufacturing motor core laminations from thin silicon steel sheets. [ABSTRACT FROM AUTHOR]

Silicon carbide was employed as a source of silicon and carbon to produce sintered silicon steels, offering the advantages of silicon addition. This work explored the effects of low SiC contents of 1.0 and 2.0 wt.% on as-sintered and as-tempered microstructures and mechanical properties of sintered silicon steels. The experimental sintered steels were produced from mixtures of pre-alloyed Fe-1.50Mo and SiC powder. The mixtures were compacted to tensile bars, sintered at 1553 K for 2.7 ks, and cooled at 9.0 K/s with N2. Sintered specimens were tempered at 873 K and held for different times. The microstructures and mechanical properties of the sintered and tempered specimens were characterized. It was revealed that the sintered silicon-bearing steels showed low temperature phase transformations under cooling at 9.0 K/s. The sintered steel produced by 1.0 wt.% SiC addition had degenerate upper bainite microstructure and its tempered microstructure was upper bainite. The sintered steel produced by 2.0 wt.% SiC addition had a microstructure consisting of bainitic-ferrite plates, martensite plates, and austenite blocks. Its tempered microstructure was upper bainite. The tempered microstructures resembled those of sintered Si-free Fe-Mo-C steels. Tempered specimens exhibited tensile strength higher but elongation lower than sintered ones attributed to carbide precipitation strengthening. [ABSTRACT FROM AUTHOR]

In recent years, the post‐harvest commercialization of fresh jujube sorting technology is backward, the efficiency of manual grading is low, and the application of machine vision technology in fruit grading has been a research hotspot. To improve the grading accuracy and speed of the fresh jujube machine vision grading machine, this study designs a method of fresh jujube machine vision grading using an electromagnetic synchronous actuator. The grading machine consists of an automatic distribution and arrangement system, an image acquisition and processing system, and a synchronous actuator assembly, which uses a sensitive electromagnet to adsorb a silicon steel switching buckling plate to execute the action. The image processing process includes an image color component, Sobel operator filtering, Otsu method binarization, and ellipse fitting to extract the color and size eigenvalues. The experimental results show that the date images can be acquired quickly and processed accurately with a processing speed of 50 ms per frame. In addition, the proposed actuator can be sensitively triggered with a response time of 40 ms. The grader successfully classified jujube into five size classes and one color class. The grading accuracy and non‐destructive rate reached 93.7% and 100%, respectively. The grading efficiency is 20 jujubes per second, with a maximum production rate of 1400 kilograms per hour. This grading machine realizes the requirements of high accuracy, high speed, and non‐destructive grading of fresh jujube and provides an important technical and theoretical basis for the development of machine vision jujube rapid grading technology. Practical applications: In recent years, sorting technology in the post‐harvest commercialization of fruits has been outdated, and manual grading has been inefficient. The application of machine vision technology in fruit grading has been a research hotspot in recent years. This study designs a machine vision grading of fresh dates with an electromagnetic synchronous actuator. The grader was composed of a roller conveyor, synchronous actuator assembly, image main processor, and actuator controlling co‐processor. Experimental results indicated that jujube images could be acquired rapidly and processed accurately, with a processing speed of 50 ms per frame. In addition, the proposed actuator could be sensitively triggered with a response time of 40 ms. Finally, the grader successfully sorted jujubes into five size classes and one color class. The grading accuracy rate and non‐destructive rate reached 93.7% and 100%, respectively. The grading efficiency was 20 jujubes per second, and the maximum productivity was 1400 kg/h. [ABSTRACT FROM AUTHOR]

Grain growth for various texture components in silicon steel was investigated via experiments and modeling. It was found that the clustered spatial arrangement of grains with specific orientations significantly altered the local environment for grain growth and consequently resulted in texture-differentiated grain size distribution (GSD) evolution. A novel local-field model was proposed to describe grain growth driven by continuous changing orientation and size distribution of adjacent grains. The modelling results show that the texture-differentiated grain growth in microstructure with grain clusters can produce a GSD with increased proportion in small-sized range and large-sized range by more than two-times, accompanied with an evident change in area fractions of various texture components. The effect of clustered spatial arrangement on grain growth can be precisely predicted, which is valuable to design and control the texture-differentiated GSD as well as the global GSD. [ABSTRACT FROM AUTHOR]

This paper explores the applicability of cryogenic permanent magnet motor stator materials for LNG pumps. First, this study selected four kinds of silicon steel sheets for motor stators tested at room temperature and ultra-low temperature and obtained the magnetization characteristics and loss characteristics of the four silicon steel sheets at room temperature and ultra-low temperature. Then, through a comparative analysis of experimental data, the applicability of silicon steel sheet material in an ultra-low-temperature environment was verified. Finally, the improved methods of the basic iron loss model of silicon steel sheets and the basic iron loss model of motors were proposed, and the accuracy and feasibility of the improved models were verified. [ABSTRACT FROM AUTHOR]

This research investigates the characteristics and performance of magnetic core materials, including Silicon Steel, Amorphous, Ferrite, and Nanocrystalline, that are suitable for use in a switched-mode power supply (SMPS). The study examines the magnetic capability of the system within a frequency range of 10–17 kHz in order to assess the effectiveness of galvanic isolation. The study presents a systematic approach and provides an illustrative example to elucidate the process of designing an effective galvanic isolation for power electronics converters. The American Wire Gauge (AWG) standard is used to determine the appropriate wire for the windings. The selection of ferrite materials N-97 and N-92 is based on their favorable characteristics, including high permeability, low losses, and a satisfactory working temperature. The paper presents three comprehensive designs utilizing Ferrite cores across several operating frequencies. In the first design, utilizing Ferrite N-97 at a frequency of 10 kHz, the combined losses from the core and winding amounted to 2.148 W. Conversely, the second design consumes 35.16 W. The galvanic losses for the third design amount to 11.58 W. Every design possesses a certain core and Bobbin form. All three magnetic designs undergo verification to ensure that they are not saturated. An in-depth analysis and simulation of a 1 kW full-bridge DC-DC converter have been validated using "Ansys Software." An investigation of magnetic performance was conducted to assess the various core materials. [ABSTRACT FROM AUTHOR]

The wettability between a Si–S steel with 0.2 wt pct sulfur and 0~3.5 wt pct silicon and a CaO substrate was investigated using a sessile drop method at 1550 °C. The equilibrium contact angle between the Si–S steel and the CaO substrate was 95, 136, 142 and 142 deg when the content of silicon in the steel was 0, 1.4, 2.8, and 3.5 wt pct, respectively. When there was no silicon in the steel, the steel hardly reacted with the CaO substrate. However, when the steel contained > 1 wt pct silicon, a reaction layer composed of CaS and 2CaO·SiO2 was generated at the interface between the molten steel and the substrate. Besides, the thickness of the reaction layer increased from 0 to 36 μm with the silicon content in the steel increasing from 0 to 2.8 wt pct, because the dissolved oxygen was reduced by silicon. However, when the silicon content increased to 3.5 wt pct, the thickness of the reaction layer reversely decreased, which was attributed to the prevention of the sulfur diffusion in the dense solid state reaction layer. [ABSTRACT FROM AUTHOR]

The effect of quenching and tempering on the microstructure, phase composition and mechanical properties of steel 0.33C – 1.8Si – 1.44Mn – 0.58Cr is investigated. The structure is studied using scanning and transmission electron microscopy, dilatometry and differential scanning calorimetry. Tensile and impact strength tests are performed. The Rockwell hardness is measured. The processes of formation of carbides in the steel at different temperatures are analyzed, as well as the influence of the structure on the mechanical properties. Quenching yields laths of martensite with carbon-saturated dislocation boundaries due to formation of Cottrell atmospheres. The internal stresses reach 40% of the yield strength σ0.2. Tempering to a temperature of 280°C causes precipitation of transition η-carbides (Fe2C) inside the laths, which depletes the martensite matrix of carbon by about 90%. This increases the yield strength by 16% to 1130 MPa despite the lowering of the internal stresses and growth of the width of the laths. Precipitation of cementite chains over the lath and block boundaries occurs in tempering at 500°C, which is accompanied by lowering of the yield strength to 1130 MPa. Calculations of the proportion of carbon atoms in the martensite shows that almost all of the carbon present in the steel goes to formation of cementite. The decomposition of martensite during tempering increases the toughness but has a minor effect on the strength-ductility parameter σr × δ (MPa ∙ %). [ABSTRACT FROM AUTHOR]

Considering the high-speed and high power density technical specifications of new energy vehicle motors, there is a growing demand for rotor strength as motor peak speeds reach 20,000 r/min and beyond. The utilization of non-oriented silicon steel with a high yield strength in rotors has emerged as a promising approach to increase motor speed. However, the magnetic and mechanical properties of high-strength silicon steel under variable temperature conditions have not been fully explored, particularly in regards to their impact on motor torque, efficiency, and speed. This manuscript investigates the behavior of high-strength silicon steel before and after annealing and at different temperatures, analyzing its influence on high-speed motor performance. The validity and feasibility of this study are confirmed through prototype testing, providing a comprehensive reference for engineering design. [ABSTRACT FROM AUTHOR]

Accurate measurement of magnetostriction is the basis for calculating the vibration of silicon steel laminated core. In this paper, a laser magnetostriction measurement system (MST500) is used to study the magnetostriction characteristics of silicon steel under sinusoidal, third harmonic, and DC bias magnetization. The magnetostrictive butterfly curves, time domain waveforms, and spectrum diagrams of silicon steel sheets under different excitations are compared and analyzed. The effects of different operating conditions on the magnetostrictive properties of silicon steel sheets were studied and analyzed, mainly including amplitude and spectrum analysis. Finally, the magnetostrictive peak to peak curves under different operating conditions were extracted, providing a data basis for the core vibration of power equipment. [ABSTRACT FROM AUTHOR]

This article introduces an isolated three-phase six-pulse rectifier using a solid-state transformer. The line frequency utility grid voltage is modulated by a frequency boost converter. This converter exists two parts. The first part is the rectifier section, and the second one is the inverter section. Then after, three-phase diode rectifier is powered by the medium frequency transformer 2 kHz to shrink the transformer size upto 20% or even 10% depensing to the frequency operating range for silicon steel core materials. The aim of this study is to shrink the occupied size of the rectifier using a higher frequency transformer. The study realizes that the grid line current has the same frequency contents as a regular three phase rectifier. In other words, the presented idea results in smaller weight and size while sustaining the performance of input current total harmonic distortion THD=31%. High power density power electronics converter would be extremely valuable for applications such as electric vehicle railways and aircraft. The proposed approach is reliable and easy to use. The solid-state transformer contributes to isolating and improving the overall converter's power density. Simulation results for the 16 kW converter were verified using MATLAB Simulink. [ABSTRACT FROM AUTHOR]

High entropy nitride (HEN) films of (TiZrHfNbTa)Nx were deposited by reactive DC magnetron sputtering, choosing 304 stainless steel and silicon wafers as the experimental substrates. The influence of nitrogen flow rate R N : N 2 /(N 2 +Ar) on the microstructure and properties of HEN films was investigated. The results showed that HEN films exhibit granular surface morphologies and internal characteristics of amorphous embedded FCC crystals, exhibiting a structure of amorphous at the lower R N (0, 2 %) and transforming to FCC crystals with preferred (111) orientation as R N increasing (6.5%–26 %), with the decrease of crystallinity and the alteration of preferred orientation from (111) to (200) at the further increase of R N at 40 %. The introduction of nitrogen led to significant improvements of film hardness (>23 GPa) and modulus (>270 GPa). When R N = 13 %, the hardness is up to 30.7 GPa, and the modulus is 340 GPa at R N = 6.5 %. The as-deposited films exhibited excellent wear resistance, and the wear rate (6.65✕10−6mm3/Nm) was the lowest when R N = 2 %. [ABSTRACT FROM AUTHOR]

Because the magnetic properties of an amorphous alloy (AA) obviously change with the change of temperature, a finite element simulation method for a motor, considering the effect of temperature, is proposed in this paper. In the early design stage of the high-speed permanent magnet synchronous motor (PMSM), the simulation of motor performance is mainly based on the magnetic performance test data at room temperature provided by the material's manufacturer. However, the influence of the temperature rise during the actual operation of the motor will lead to large errors between the simulation results and the measured results. Therefore, it is of great practical significance to measure the magnetic properties of the AA at different temperatures and use them for simulation purposes. In this paper, the magnetization characteristics and iron loss characteristics of the AA and silicon steel (ST100) used for comparison are measured at different temperatures, and the iron loss separation of the two materials at different temperatures is completed, and the hysteresis loss coefficient and eddy current loss coefficient at different temperatures are obtained. On this basis, the performance simulation of a motor model is carried out. The more accurate simulation method proposed in this paper can provide a reference for the design of AA motors in industry. [ABSTRACT FROM AUTHOR]

The magnetic properties of a 0.10 mm ultra-thin, grain-oriented (UTGO) silicon steel and an Fe-based amorphous (FBA) alloy under sinusoidal excitation were experimentally researched, and the magnetic field strength and iron loss of the two materials under different frequencies and magnetic densities were obtained. Based on the measured data, the magnetization and loss characteristics of the two materials were analyzed and compared. Furthermore, two Epstein square ring models of the same dimensions and different materials were designed, and the reliability of the models was verified. Then, the electromagnetic characteristics of the two Epstein square ring models at higher and lower frequencies were calculated using the finite element method, and the iron losses were obtained and compared. The results show that the FBA alloy has good application characteristics at low frequencies and low power, and the 0.10 mm UTGO silicon steel has good application characteristics at high frequencies and high power. This research provides important data, promoting the application of these two materials in new energy equipment. [ABSTRACT FROM AUTHOR]

Understanding the recrystallization behavior of cold‐rolled silicon steel during continuous heating is essential for optimizing continuous annealing parameters and accurately controlling material performance. To address the limitations of isothermal annealing studies in interpreting actual continuous annealing processes, this study investigates the recrystallization kinetics of Fe–2.3 wt%Si steel using a continuous heating three‐point bending method. The method effectively determines the characteristic recrystallization temperatures. Interestingly, these recrystallization characteristic temperatures remain unaffected by the initial load but shift toward higher temperatures with increasing heating rates in the range of 5–15 °C min−1. The average activation energy of recrystallization is estimated to be 144.5 kJ mol−1, comparable to the value of 147.0 kJ mol−1 obtained from the isothermal process through microhardness measurement. The recrystallization kinetics, described by an extended version of the Ozawa–Flynn–Wall model, exhibits excellent agreement with experimental evaluations. By combining the present processing technologies with continuous heating recrystallization kinetics, different recrystallization temperatures and times can be determined, offering valuable insights for optimizing annealing processes. [ABSTRACT FROM AUTHOR]

The intense magnetic field surrounding the electronic system in the ITER Tokamak necessitates the use of magnetic field shielding to protect electronic devices from failure. To ensure that the components installed in these areas can withstand ITER's magnetic environment, they must be tested beforehand for magnetic field tolerance. This paper presents a magnetic shielding design for the Radial X-ray Camera (RXC) electronic system in ITER, silicon steel sheet is used as shielding material. The design scheme was simulated and analyzed using Ansys Maxwell software, and the shield shell was designed and optimized to reduce the magnetic induction intensity from 120 mT to less than 60 mT. To determine whether the magnetic field tolerance capability of the shield and electronic system meets ITER's requirements, tests were conducted. Based on the experimental results, it has been observed that the shield is effective in shielding the magnetic field to 50–60 mT. Furthermore, the electronic system has been tested under a magnetic field intensity of 140 mT and 180 mT, and it has been found to be functioning normally, thereby meeting the requirements of ITER. [ABSTRACT FROM AUTHOR]

The medium frequency coreless induction furnace has gradually replaced the cupola in cast iron melting. However, induction coils at the bottom 1–6 turns can experience issues posing production and resulting safety risks. A kind of coil interturn breakdown failure caused by black attachment has occurred in our engineering practices. To explain the attaching and breakdown mechanism, an experimental investigation and detailed analysis of physical and chemical processes are performed. SEM, EDS and Fourier transform infrared spectrum results show that the attachment is primarily composed of free carbon, with a mass and atomic fraction of 62 and 71%, respectively. There were no C-H bonds in the powdered black attachment. The redox reactions of SiO2 and C, hydrogen and disproportionation reactions of CO and the ionization reactions of H2O contribute to the C transfers. The physical isolation of the Isoplan board, which prevents the mixture of CO, CO2, H2, H2O, and O2 from diffusing, causes C deposited only on the coil surface. The conductive carbon deposition in a moisture environment reduces the insulation degree of interturns and generates high-voltage discharge between adjacent coils. According to the findings, three improvement strategies are proposed and validated: (1) drilling holes in the Isoplan board; (2) unplugging the silicate insulating cloth in the lining sintering; and (3) as new lining is put into service, silicon steel sheets are prioritized for use as furnace charge. [ABSTRACT FROM AUTHOR]