Induction Furnace Research Articles

Iron making in induction furnace for casting steel billets

Emmar Steel (ES) is an integrated steel plant having a production capacity of about 0.5 million tons of steel per annum. ES consists of two Mini Blast Furnaces (MBF), an Energy Optimizing Furnace (EOF), two Induction Furnaces (IF), a Ladle Refining Furnace (LRF) and a four-strand Continuous Casting Machine (CCM). ES is producing 130 mm2 mild steel billets to cater to the needs of rolling mills in Syria.War and sanctions on Syria pose problems in importing raw materials, equipment, spares and consumables, which leads to intermittent stoppage of MBF operation hampering production. In this scenario, when MBF was not in operation, the production of steel depends solely on induction furnaces.Due to increased generation of scrap during war time, steel scrap is available in plenty and at cheaper prices in Syria when compared to international market prices. Use of mixed scrap in induction furnaces poses problems in controlling chemistry of steel leading to the production of unwanted and unmarketable “off grades”. The present paper discusses a novel method of producing hot metal (liquid iron containing carbon around 3.0%) in IF which is subsequently converted into steel in EOF and cast into 130 mm2 billets.

Sound barrier behavior of geopolymer composite manufactured from industrial waste

Noise pollution is an invisible hazard faced in industries, roads, and public places etc., and has become part of daily life. Noise affects the psychology and physiology of animals and humans and can lead to accidents and health issues. Noise can be reduced by using active or passive materials. Active mediums are in which enormous amount of external energy is used to balance the noise energy, whereas in passive medium sound is absorbed such as by using insulating materials. Conventionally, passive sound barrier panels made of concrete are used, which involve energy intensive manufacturing processes as they use Ordinary Portland Cement (OPC). The concrete sound barrier panels have a large carbon foot print as it releases carbon dioxide (CO2) during manufacture of OPC and during hydration of concrete. The global warming is caused due to emission of greenhouse gases mainly comprising of carbon di oxide. The cement industry emits 5 to 8 % of the world’s CO2 emissions and thus an alternate building material is required. The search for an ecofriendly green binding material to replace cement leads to discovery of geopolymer. Geopolymers are ceramic materials comprising of polymers made of inorganic aluminosilicate and fabricated by alkali activation of aluminosilicates. In this research work, the induction furnace (IF) slag and Class F fly ash are utilized along with manufactured sand (M Sand) an alternative material for the river sand, as fine aggregate. The environmental advantage of this material is that the ingredients are industrial waste and the geopolymer has negligible carbon foot print. The geopolymer composite specimens were subjected to sound absorption test using impedance tube studies and found to exhibit an increased sound absorption coefficient (α) between 0.2 and 0.35 in the frequency range of 1200 Hz to 6300 Hz. This study establishes that the geopolymer manufactured using industrial waste material can be effectively utilized as sound absorption material and can assist in mitigating noise pollution.

Geopolymer based foams from steel slag – A green technology

The Induction Furnace slag is an industrial byproduct obtained during the manufacture of the steel. Due to its hardness and incompatible chemical composition it’s not used in cement industries and hence is wasted in landfills. A vast quantity of steel slag from the numerous steel industries situated in India. The proper utilization of the steel slag shall be needed to prevent the pollution caused by its disposal as landfill. Since it is a by-product from steel industry, it is available free of cost. The geopolymer is a green technology of making concrete like material without the use of cement and has minimal carbon foot print. The geopolymer is prepared through alkali treatment of industrial wastes like steel slag and fly ash, leading to formation of alumina-silicate based composite. The geopolymer has good potential in the application in Non-load bearing structures. In this paper the fabrication of geopolymer foams and their application is discussed. The geopolymer foams could be engineered to form foams and their application is discussed. The geopolymer foams could be engineered to form foam having isolated cells or interconnected cells to cater to various applications. The geopolymer foams are a green technological option to utilize industrial waste and produce products useful to the society at a cheaper cost.

Hardening of bucket teeth made from creusabro 8000 steel by using the induction hardening method

Excavators are often used in mining projects such as for penetrating, excavating, dredging, gouging, and crushing mineral rocks. Bucket teeth are an excavator component that is often being replaced due to failure. The most common failure mode that occurred in bucket teeth was wear on the tip or front section of it. To reduce the wear of the bucket teeth material then its hardness should be increased. As the hardness value increases, the resistance to wear increases. The bucket teeth were made of Creusabro 8000 steel and a hardening process was then carried out on the front section of the bucket teeth components by using an induction furnace. The power used in the induction furnace varies from 28, 35, 42 and 49 kW (kilowatts) and the holding time varies between 3 and 5 minutes. The heat treatment process used oil as a cooling medium. The analysis was carried out to determine the area that experienced an increase in hardness and its occurred microstructure. Microstructure examination was carried out with an optical microscope, and hardness test by using a Vickers microscopy. It can be concluded from the result of the analysis that the large area experienced an hardness increase is directly proportional to the electric current magnitude and holding time. The microstructure has changed from fine pearlite to martensite thus hardness of Bucket Teeth can be increased up to 100% of the initial hardness.

An experimental study on quenching of metallic spheres in seawater

Motivated by quenching of melt droplets and debris particles in seawater during a hypothetical severe accident of light water reactors (LWRs), the quenching process of stainless-steel spheres in a seawater pool was investigated in the present study. The polished spheres were pre-heated up to 1000℃ in an induction furnace with inserted atmosphere, and then immersed into the subcooled water pool in a chamber made of transparent quartz. A thermocouple was embedded in the center of the sphere to measure the history of the sphere’s temperature, while a high-speed camera was employed to record the quenching process and vapor film dynamics. Quantitative data, e.g. film thickness and oscillation, of the vapor film evolution during the quenching process were obtained through an image processing program developed on the MATLAB platform.The experimental results indicated that the quenching rate was higher in seawater than in deionized water, and the vapor film collapsed at a temperature higher than the Leidenfrost temperature in deionized water. The trend appeared more significant with increasing subcooling of water. The comparison of the quenched spheres suggested the surface of the sphere in seawater achieved higher degree of discoloration and roughening than that in deionized water, probably due to the additives of salt which change water properties. The image processing and analysis revealed that the vapor film had different thickness profile along the upper and lower hemispheres, and the averaged film thickness was smaller in seawater than in de-ionized water during the stage of stable film boiling. The vapor film was thinning and oscillating with time, and its fluctuations appeared different frequencies and amplitudes at the upper and lower locations, which may explain the mechanism of the earlier collapse of vapor film in the quenching process of a high-temperature sphere in seawater.

Thermodynamic Formation and Three-dimensional Characterization of MnS–MgAl<sub>2</sub>O<sub>4</sub> Composite Inclusions in Steel

The distribution and morphology of inclusions in steel have an important effect on the quality of steel. It has been proved that the oxide inclusions can be modified into small and dispersed spinel inclusions by adding proper amount of Mg in steel. The MnS-MgAl2O4 composite inclusions are formed with the core of MgAl2O4 inclusions during the solidification process of molten steel, which has deforming ability and can improve the properties of materials steel. However, the investigation of the control of the composite inclusions is limited by the lack of understanding structure of the inclusions. In this study, the Mg treated steel samples were prepared by induction furnace in this study. In the experiment, SEM-EDS was used to characterize the samples, and thermodynamic calculations were used to describe the evolution mechanism of inclusions and MnS-MgAl2O4 composite inclusions formed in steel samples with different Mg contents. The atomic mismatch calculated between MnS and MgAl2O4 proves that they can nucleate effectively. The three-dimensional (3D) morphology of the composite inclusion of MnS-MgAl2O4 in steel samples were observed by using the X-ray Micro-CT in the beamline of BL16U2 at Shanghai Synchrotron Radiation Facility (SSRF). It is proved that MnS and MgAl2O4 phases exist in the form of co-associated, which is valuable for the control of composite inclusions in steel. The current work provide a powerful method to analyze the detailed structure of the composite inclusions in the steel.

Utilization of Steel Slag as a Soil Amendment and Mineral Fertilizer in Agriculture: A Review

The gradual increase in industrial wastes allowed the utilization of these wastes in different areas. Steel slag, one of the industrial wastes, is formed during the reduction of molten crude iron to molten crude steel in basic oxygen furnaces (BOF) or scrap to molten crude steel in electric arc furnaces (EAF) and induction furnaces (IF). Removal, storage, or disposal of steel slag is an important environmental and economic problem. Steel slag offers opportunities to be used as an alternative material in various areas and contributes to the national economies through recycling. This research provides information about the studies and application examples on the use of steel slag as a soil amendment and mineral fertilizer in the world. This usage allows reducing the consumption of natural resources and providing great agricultural, environmental, and economic gain by minimizing the negative environmental effects of steel slag.

Towards net zero emissions, recovered silicon from recycling PV waste panels for silicon carbide crystal production

The high rate of PV adaptation around the world requires a strategy for recovery of the materials from PV waste panels and a circular market development. In particular, the silicon recovered from the PV cells can be used in different applications. A valuable acquisition is to refine the recovered silicon at metallurgical grade to a high level of purity namely electronic grade silicon which in conjunction with graphite can be the raw material for silicon carbide crystal production. Based on a comprehensive and critical review of the latest research and development of relevant technologies, a manufacturing process is proposed to increase the usage of renewable resources, reduce the energy consumption and CO2e emissions. The recovered silicon from recycling PV waste can reduce the CO2e emissions to a third of what is involved in the current carbothermic reduction of quartz in an induction furnace. Based upon the thorough evaluation of available evidence, a continuous coupled process is envisaged where the upgraded metallurgical grade silicon from recycling PV waste undergoes further vacuum and gas refining to the electronic grade silicon. Then the purified liquid silicon enters a vertical Bridgeman furnace for silicon carbide crystal production through a bottom seeded solution growth process. Considering the silicon melting point at 1410 °C, omitting a solidification/ meting step after vacuum/gas refining leads to energy and material saving. The continuous method can reduce the CO2e emissions up to 75% compared with the current silicon carbide production through Acheson process.

Effect of the intercritical annealing in the formability and microstructure of a medium Mn steel sheet

A medium Mn steel (MMS) was cast by employing a vacuum induction furnace. After that, the steel was hot rolled (HR) in order to achieve a final thickness of 1.4 mm. The microstructure of the sheet was found to be composed of martensite and a little amount of austenite, the Ultimate Tensile Strength (UTS in this processing condition was close to 1600 MPa and a negligible elongation was found. An intercritical annealing (IA) heat treatment was applied to the steel to promote the austenite reversion and increase its amount and stability. Previous thermodynamic simulations and experimental results were used to determine the temperature and time parameters of the IA. After the steel was subjected to this heat treatment, it exhibited an elongation close to 35% and an UTS close to 1100 MPa. Bendability testing was carried out in that condition in order to correlate it with the microstructural changes in the sheet. It was found that the critical bending angle was higher in the IA condition in comparison with the HR state.

Microstructures and properties of Ni-Si precipitation strengthened phosphor bronze

To strengthen phosphor bronze, this work attempted to form precipitate nanoparticles in the matrix by adding alloying elements. First, Ni and Si were identified as alloying elements through mixing enthalpy analysis. Then, Cu-8Sn-0.1P, Cu-8Sn-0.1P-0.5Ni-0.12Si, Cu-8Sn-0.1P-1Ni-0.24Si, and Cu-8Sn-0.1P-2Ni-0.48Si alloys were prepared by intermediate frequency induction furnace. After that, the microstructures of these alloys were characterized and their properties were tested. Experimental results indicated that Ni31Si12, Ni2Si, and Ni5P4 phases are newly formed in the as-cast microstructure after adding Ni and Si. At the same time, the eutectoid size of α-Cu and Cu41Sn11 in the as-cast microstructure of Ni-Si added phosphor bronze is reduced, the secondary dendrite arm spacing is reduced, and the segregation is also improved. After aging treatment, nano-sized cellular Ni2Si and trace Ni5P4 phases are precipitated in the Ni-Si added phosphor bronze. With the formation of nanoprecipitates, Ni-Si added phosphor bronzes show excellent precipitation strengthening effect after aging treatment, and the electrical conductivity of Cu-8Sn-0.1P-0.5Ni-0.12Si and Cu-8Sn-0.1P-1Ni-0.24Si alloys is also slightly higher than that of Cu-8Sn-0.1P. This study provides a new solution for strengthening phosphor bronze, enabling phosphor bronze alloys to meet higher performance and broader applications.

Ranking of Injection Biochar for Slag Foaming Applications in Steelmaking

The electric arc furnace (EAF) has the potential to significantly contribute to the decarbonization of the iron and steel industry. However, during EAF steelmaking, carbon still needs to be injected into the molten slag to initiate slag foaming, which is beneficial to the energy efficiency and protection of the furnace. To move away from fossil carbon, biocarbon has gained attention as an injection carbon agent. In this study, two biochar candidates were added to the molten slag layer of an induction furnace for steel melting, to simulate EAF steelmaking conditions. The resultant slag foaming height was measured, and a ranking in comparison to two fossil carbon candidates was developed. The results indicate that the injection biochar sample, in the form of a bio-briquette, has a considerable degree of slag foaming capacity. More work is ongoing to develop a standardized testing methodology of ranking various injection biochar candidates for their suitability and qualification for use on a larger scale.

Hot-rolled Al-added medium Mn steel (Fe-8Mn-2.85Al-1Si-0.2C): Microstructural evolution and tensile behavior

In this study, a low Al (<3%) added medium manganese steel has been developed through melting casting route in an open-air induction furnace. The cast steel ingot has been intercritical annealed at 720 °C after hot deformation, that includes hot forging and hot rolling treatment, respectively. Microstructure characterization coupled with X-ray diffraction (XRD) has been performed after each processing step to understand the extent of austenite formation and its subsequent transformation to ferrite/martensite. The processed steel possesses the ultimate tensile strength, yield strength and ductility of 1000±20 MPa,700±10 MPa and 18.5 ± 0.5, respectively. To understand the possible cause of enhanced strength and deformation mode rietveld analysis has been carried out. It reveals that developed (final processed) steel possesses ∼18% (volume%) of austenite that subsequently reduced to ∼6.139% after tensile testing, indicating significant transformation of austenite to martensite (continuous and enhanced TRIP effect). The morphological characteristic of martensite in developed steel has been investigated using transmission electron microscopy (TEM). It reveals lath morphology of martensite due to low carbon content. The TEM and 3D atom probe analysis reveals the precipitation of intergranular type kappa (k) carbide in intercritically annealed specimens due to probable segregation of C and Al. However, volume fraction of the same is low. The SFE of the steel has been found to be ∼16 mJ m− 2, calculated by the modified Olson and Cohen method that also concludes TRIP is the preferred deformation mechanism in the developed steel.

Effect of small vanadium addition on the microstructure, transformation temperatures, and corrosion behavior of a Cu72Al17Mn11 shape memory alloy

In the present work, effects of 0.1 at.% and 0.2 at.% vanadium content on the microstructure, transformation characteristics and corrosion behavior of the Cu72Al17Mn11 shape memory alloy (SMA) have been investigated by means of OM, SEM, XRD, DSC measurements and corrosion test. The alloys were produced in an induction furnace under air atmosphere. The results indicate that microstructure at room temperature consisted of a mixture of β3(L21) parent phase with 0.06–0.08 at% of vanadium into solid solution, small amounts of a cubic bcc δ(V,Mn) precipitate, β1′(18R) and γ1′(2H) martensites. The small addition of vanadium contributes to the induction of martensite γ1′ and broads the hysteresis of the alloys. Thermal analysis evidences the shift of Af, Ms to higher temperatures, showing multi-stage phase transformations of the reaction β1′→γ1′→β3, which results in increased values of ΔHM→A, ΔSM→A, ΔGe. The addition of V also interfered in the corrosion resistance of the alloy. Electrochemical measurements were carried out to evaluate the corrosion resistance alloys. With the results obtained, an increase in corrosion resistance was observed with the increase in the vanadium content in the alloy. The results of this work provide an important systematic analysis for the development and application of corrosion resistant CuAlMn SMA.

Phosphorus Partition Between Liquid Crude Steel and High-Basicity Basic Oxygen Furnace Slags Containing V2O5

The influence of V2O5 on the phosphorus partition between liquid crude steel and heterogenous basic oxygen furnace (BOF) slag with CaO/SiO2 = 4.2 was investigated at a temperature of 1600 °C in a middle frequency induction furnace. Thereby the phosphorus transfer from “steel to slag” as well as from “slag to steel” was studied over a holding time of 60 minutes. The measured results were shown as phosphorus partition and phosphorus capacity and compared with the experimental values from the literature. It was found that V2O5 in highly basic BOF slags decreases phosphorus partition and phosphorus capacity. In addition, the resulting slags were investigated using a scanning electron microscope (SEM).

Experimental Investigation on Mechanical Properties of AA2195-based MMCs for Space Applications

Background:: The modern Aluminium-Copper-Lithium (Al-Cu-li) based composites have a great demand in aerospace applications due to their lightweight, high strength, high stiffness, and superior mechanical properties. Objective:: The present study explored the effect of reinforcements like graphite and boron carbide on the mechanical behaviour and microstructure of AA2195 composite Methods:: The Medium Frequency Induction Furnace (MFIF) was used to fabricate the composites with two factors each at four levels ordered in Taguchi L16 orthogonal array. Results:: The microstructures revealed that the reinforcements were distributed uniformly throughout the composite. The elemental investigation observed by X-ray diffraction (XRD) revealed that the formed intermetallic compounds (IMCs) helped in refining the microstructure and further increasing the mechanical properties. Conclusion:: The composite fabricated at 8% boron carbide (B4C) and 6% graphite (Gr) exhibited better ultimate tensile strength, % elongation, and hardness as 190.74 MPa, 0.58, and 87.2VHN, respectively. conclusion: The composite fabricated at 8 other: .

Effect of Al and MgO on the simultaneous alloying of diamond wire saw silicon waste and Ti-bearing blast furnace slag

Diamond wire saw silicon waste (DWSSW) and Ti-bearing blast furnace slag (TBFS) are industrial solid wastes that contain large amounts of Si and Ti, whose accumulation unnecessarily wastes resources. In this paper, DWSSW and TBFS were mixed and melted in an induction furnace by simultaneous alloying, and Ti and Si were recovered by a Si-Ti alloy. In addition, the optimal material ratio of DWSSW and TBFS was determined. 10–30% reducing agent Al and 5–15% fluxing agent MgO were added to explore the effect of additives on the co-processing of DWSSW and TBFS. The results showed that Al promoted the reduction of Ti and the recovery of Si. When 20% Al was added, the recovery ratio of Ti in TBFS reached 95.62%, and the recovery ratio of Si reached 80.53%. Adding MgO changed the slag composition, simplified the slag structure, and reduced the viscosity. The recovery ratio of Ti from TBFS reached 96.18% when 15% MgO was added. The two additives promoted the alloying co-processing of DWSSW and TBFS, which provided a more efficient clean utilization process for these two solid wastes.

A numerical study on the levitation system for droplet preparation in a fuel-coolant interaction experiment

The MISTEE facility at KTH was designed to investigate the process and phenomena of a molten droplet falling into a water pool that may be encountered in fuel-coolant interactions (FCI) during a severe accident of light water reactors. An aerodynamic levitation mechanism is proposed to hold the molten droplet during its preparation (melting and heating up to a prescribed temperature) in an induction furnace. The crucible is flushed with argon through an injection nozzle at the bottom to prevent the droplet from falling out of the crucible. A numerical simulation of the aerodynamic levitation system is performed in the present study with the objective of determining and optimizing the design. The problem was simplified as an isothermal two-phase flow in an axisymmetric geometry. The simulation is realized through ANSYS Fluent v17 platform, which employs the VOF method to track interfaces between two phases and the SST k-omega model to describe turbulence flow of argon gas. The numerical model is validated against tests performed in the MISTEE facility after mesh sensitivity study. It is then applied to investigate the impacts of various parameters on the facility levitation capability and the droplet stability. According to the simulation results, stable molten droplets can be obtained in the designed experimental setup. The simulation also provides the appropriate values of argon inlet velocity and sample mass at which a stable droplet can be obtained inside the crucible before its discharge. Either higher or lower inlet velocity will destabilize the formation of the droplet. Considering the temperature-dependent melt properties, both surface tension and viscosity affect the movement and deformation of the molten droplet. The wettability of melt on the crucible wall is critical to droplet formation, and it is found that a poor wettability can ensure the levitation of droplet.

Production of the steels of special duty at the "Lasmet" Ltd. for developing reference samples

A technology for production of special steels of a given chemical composition for reference samples is considered. The developed technology includes smelting of the steel (alloy) of a given composition in a vacuum induction furnace using high purity charge materials followed by forging of the ingot in several stages on hammers with a mass of the falling part 7 and 3 tons and rolling on a universal mill 250 into finished bars. Alloys of several grades were preliminarily smelted in a laboratory vacuum induction furnace in accordance with the chosen scheme of metal microalloying and then subjected to hot deformation and hot plasticity tests. The hot plasticity was evaluated on a plastometer designed by the Research Institute of Metallurgy (Chelyabinsk). The data obtained during the research made it possible to adjust the technology of smelting (by optimization of the amount of microalloying elements) and hot deformation of metal (by the choice of heating temperature for forging) in conditions of pilot production. This technology was repeatedly used to obtain metal products which formed a base for reference samples of LG32 - 36, LG56 - 64, NG15 -17 series and some others manufactured at the Institute for Certified Reference Materials (Yekaterinburg). The developed technique ensures a high purity of the produced metal in terms of dissolved gases, harmful impurities and non-metallic inclusions, which made it possible to provide the customer with high-quality metal in a short time frame.

Numerical Studies of Processes in an Induction Furnace with a Cold Crucible for Vitrification of High-Level Waste That Contains Noble Metals

Numerical Studies of Processes in an Induction Furnace with a Cold Crucible for Vitrification of High-Level Waste That Contains Noble Metals

DISTRIBUTION OF RADIOACTIVE ELEMENTS DURING SLAG REMELTING OF STRUCTURAL MATERIALS OF VVER FUEL ELEMENT SHELLS

At the radiochemical plant of FSUE “PO “Mayak” in the process of processing spent nuclear fuel (SNF), about 170 tons/year of metal radioactive waste (MRW) are formed, mainly represented by fuel element shells structural materials (SM) containing residual amounts of radionuclides after fuel dissolution, and spent fuel assemblies (SFAS) sent to storage. It is possible to achieve compaction and decontamination of MRW by a method based on slag remelting in an induction furnace with a cold crucible. In order to establish the distribution of actinides and fission products (FP), thermodynamic slag remelting process modeling of the VVER-1000 reactor plant SM fuel rods shells and SFAS, experimental data obtained verification were carried out. The most probable distribution of actinides and FP by melting products is shown. Most of the curium and americium are concentrated in the metal – 99 and 94 wt %, respectively. The maximum extraction of uranium into the slag phase in the form of UO2 dioxide is up to 40 wt %. The distribution of plutonium in the temperature range of 1500–2000°C over the slag (in the form of PuO and PuO1.61 oxides) and metal phases occurs in almost equal proportions. It has been established that up to 99.78 wt % cesium, the content of europium and americium is 0.05 and 0.17 wt %, respectively.