Medium Frequency Induction Furnace Research Articles

Influence of Rolling and Ageing On Mechanical Properties of AA2195 Based Metal Matrix Composites

The modern Aluminium based composites have a great demand in the field of aerospace applications due to their lightweight, high strength, high stiffness, and superior mechanical properties. The main objective is to fabricate the AA2195 composites through Medium Frequency Induction Furnace (MFIF) with Taguchi L16 design of experiments, hot rolling process and heat treatment of composites is done and then compare the mechanical properties of hot rolled and heat treated AA2195 composite with casted composite. It is analyzed the effects of reinforcements like graphite and boron carbide on the mechanical behaviors and microstructure of both AA2195 composites. The microstructures revealed that reinforcements were distributed uniformly throughout the composites. It observed that the elemental investigation on SEM and XRD for both the composites showed that formed intermetallic compounds (IMCs) helped refine the microstructure and further increased the mechanical properties. The hot rolled and heat-treated AA2195 composite fabricated at 8% B4C and 6% Gr exhibits the more enhanced ultimate tensile strength, hardness, and reduction in density, % elongation compared to the casted composite. The rolling process is used to reduce the porosity of the composite. In contrast, heat treatment enhances the composite's mechanical properties like strength and hardness.

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: .

Influence of Milling Time and Ball-to-Powder Ratio on Mechanical Behavior of FeMn30Cu5 Biodegradable Alloys Prepared by Mechanical Alloying and Hot-Forging

FeMn30Cu5 is a biodegradable and multi-component alloy that can be used to repair bone defects in load-bearing parts in the medical field. This work focuses on studying the influence of milling time and ball-to-powder ratio (BPR) on the mechanical behavior of FeMn30Cu5 alloys via mechanical alloying and hot-forging. Three different milling times (1, 5.5, and 10 h) and BPRs (5:1, 10:1, and 15:1) were used as the main independent variables. MA was performed at 300 rpm in ethanol; the synthesized powders were dried, hot-compacted at 550 MPa, and sintered under an inert atmosphere (1000 °C, 15 min) using a medium-frequency induction furnace and hot-forging. The mechanical behavior in terms of Vickers hardness, compressive stress–strain curves, and percentage theoretical density was investigated. This experimental work revealed that both milling time and BPR significantly influenced the grain size reduction owing to variations in the severe plastic deformation and mechanical collisions produced by the milling medium. The hardness and ultimate strength of the FeMn30Cu5 alloy processed at 10 h and 15:1 BPR were 1788.17 ± 4.9 MPa, which was 1.5 times higher than those of the same alloy processed at 1 h and 5:1 BPR (1200.45 ± 6.5 MPa). Austenite iron (g-Fe), ferrite-iron (a-Fe), a-Mn, and a-Cu phases were observed in XRD and SEM images. The formed a-Mn and a-Cu overlapped with the g-Fe lattice because of the diffusion of Mn and Cu atoms during sintering and hot-forging. The incorporated 30 wt.% of Mn and 5 wt.% of Cu stabilize the austenite phase (good for MRI scans in medical applications), which contributed to promoting superior mechanical properties with milling time (10 h) and BPR (15:1) due to severe structural defects.

Microstructure and properties evolution of Cu-Ti-Cr-Mg alloy during equal channel angular pressing at room temperature and cryogenic temperature

A Cu-2.5Ti-0.4Cr-0.1Mg (wt%) alloy was prepared in a vacuum medium frequency induction furnace. The evolution of the microstructure and mechanical properties of the samples deformed by equal channel angular pressing (ECAP) at different temperatures was investigated by hardness tests, tensile tests, optical metallography observation, X-ray diffraction and electron back-scattered diffraction. The cryogenic-temperature-deformed (CDed) samples have a little higher hardness than room-temperature-deformed (RDed) samples at any given ECAP pass. After 8 ECAP passes, the yield strength of CDed and RDed samples is close to each other, with the value of 812 ± 17 MPa and 793 ± 25 MPa, respectively. ECAP deformation significantly refines the grain size of the alloy due to the dislocation subdivision and twin fragmentation, and the average grain sizes of RDed and CDed samples after 8 passes are about 0.32 µm and 0.37 µm, respectively. Calculation results show that dislocation strengthening plays a key role in increasing the strength of ECAPed samples.

Deoxidation and inclusion evolution of FeNi-based expansion alloy smelted by slagging method

ABSTRACT The composition of CaO-SiO2-MgO-Al2O3-CaF2 slag was designed by thermodynamic calculation of [Al]-[O] equilibrium of FeNi-based expansion alloy. On this basis, the deoxidation and inclusion evolution in the process of slagging and smelting FeNi-based expansion alloy in the medium frequency induction furnace were investigated. The results show that the oxygen content in the alloy melt is mainly controlled by the [Fe]-[O] equilibrium, and the change trend of the equilibrium oxygen content calculated by [Fe]-[O] equilibrium is consistent with the actual oxygen content. The total oxygen content of the final ingot is 45 ppm. After Al deoxidation in the melting process, the inclusions in the alloy are transformed into composite oxide inclusions rich in Al2O3 and MgO. After final deoxidation with Si-Ca alloy, the contents of Al2O3 and MgO in the inclusions decreased significantly, while the CaO content increased. And there are mainly CaO-SiO2-MgO-Al2O3 composite oxide inclusions in the ingot.

Investigation on Energy-Effectiveness Enhancement of Medium-Frequency Induction Furnace Based on an Adaptive Chaos Immune Optimization Algorithm with Mutative Scale

Based on the chaos algorithm and immune algorithm theory, an adaptive chaotic immune optimization algorithm (ACIOA) with a mutative scale was proposed and subsequently validated by the experiment result in this paper, and then the adaptive chaotic immune optimization algorithm with mutative scale was applied to investigate the performance characteristics of the medium-frequency induction furnace. The obtained results include the effects on the performance characteristics of a medium-frequency induction furnace of the diameter of the heated cylindrical material, the thickness of the crucible wall, the fullness degree of the induction coil, the ratio of diameter to current penetration depth, and the power frequency. The results showed that the optimization algorithm could continuously modify the variable search space and take the optimal number of cycles as the control index to carry out the search. In addition, the suitable ratio of diameter to current penetration depth was between 3.5 and 6.0, and was beneficial to the improvements of in power factor and thermal efficiency. This method had the characteristics of small calculation delay, high anti-noise ability, and high detection rate. Moreover, the maximum errors of KFF, Random, and PSO were 6.4%, 6.2%, and 5.4%, respectively. The improved method had good estimation accuracy and an excellent global optimization. Meanwhile, the suitable ratio of diameter to current penetration depth, the thickness of crucible wall, and power frequency were beneficial to the improvements in power factor and thermal efficiency. Thus, the finding is helpful as a guide to determining the design of a medium-frequency induction furnace, which may be of interest for improvements in performance under different operating conditions.

Research and Comparative Analysis of Wear Resistance of Cast Grinding Media From Chromium Cast Irons

A study was made of the impact-abrasive wear resistance and impact resistance of grinding bodies cast in a multi-place mold. Three types of chromium cast irons were adopted for the study: low chromium (~1% Cr), medium chromium (up to 5% Cr) and high chromium (up to 20% Cr). The macro- and microstructure of these alloys as a material for cast grinding balls has been studied. Installed an increase in the impact-abrasive wear resistance and impact resistance of such products with an increase in the mass fraction of chromium in cast iron due to the formation of carbides of the (Fe, Cr)3C and especially (Fe, Cr)7C3. Balls were cast in multi-seat chill molds. Cast iron was smelted in a medium-frequency induction furnace, such as IChT, with the main lining on a charge of pure pig iron and steel low-carbon scrap. The temperature of cast iron production was 1500 °C. Liquid cast iron was subjected to alloying with medium carbon ferrochrome. The wear resistance of cast irons was determined on samples cut from balls in the radial direction. The tests were performed in a laboratory mill When tested for impact resistance, the grinding ball received a striking blow of mass 50 kg, falling from a height of 0,5 m. The frequency of application of dynamic loads was 10 beats per minute. Impact resistance was determined by the average number of impacts sustained by the grinding body prior to destruction. Nevertheless, significant excess of the cost high-chromium over low-chromium cast iron forces us to agree with the opinion of the majority of researchers and the practice of production of such metal products. In today's conditions, low-chromium white cast iron is an economically viable material for grinding media.

A Study on the smelting process of low carbon steel scrap and sponge iron in medium frequency induction furnace for production of front bumper beams

MS1200 steel grade is now widely utilized in the automotive sector because it is a good solution for the current trend of vehicle chassis frame construction. This research presents a technology procedure for producing MS1200 steel grade from low carbon steel scrap and sponge iron – a product of MIREX Vietnam. The smelting using up to 30 % sponge iron briquettes combined with low carbon scrap, FeSi, FeMn, FeCr, FeTi,… was realized in a medium frequency induction furnace. The heat treatment for forged steel was performed to obtain required properties. The steel product has the following properties: tensile strength σb = 1280 MPa, yield strength σ0.2 = 990 MPa and impact toughness ak = 769 J/mm2, that meets the need of industrial use.

Photoluminescence characteristics and energy transfer phenomena in Ce3+-doped YVO4 single crystal

Abstract The undoped YVO4 and Ce3+-doped YVO4 single crystals have been successfully grown by the Czochralski method in a medium frequency induction furnace. The X-ray diffraction patterns testified that all samples exhibited the pure tetragonal YVO4 crystalline phase without any parasitic phases. The optical properties of Ce3+-doped YVO4 single crystals with different doping concentrations were investigated via a combination of absorption, emission, and excitation spectra. Dependence of luminescence and absorption intensity on Ce3+ doping concentration was discussed at different excitation wavelengths. The typical transitions of Ce3+ ions and the unusual intrinsic luminescent phenomena of VO 4 3 − {\text{VO}}_{4}^{3-} groups were observed and investigated in Ce3+-doped YVO4 crystals. More attentions were paid to ascertaining the corresponding transition states, analyzing luminescent mechanism, and revealing the energy transfer from VO 4 3 − {\text{VO}}_{4}^{3-} to Ce3+ ions. In addition, the CIE chromaticity coordinates and correlated color temperature were calculated on a basis of emission spectra under different excitation wavelengths.

On-Condition Maintenance for Medium Frequency Induction Furnace (Corless Type).(Dept.M)

In this investigation, the maintenance problem of induction furnaces which usually faces the foundry men has been examined, using on condition maintenance. This is for 11ning, and also to know when to take a decision to change the lining of furnace. This can be reached by continuous measuring of furnace resistivity. In other words. the power should be stopped when the reg18tivity of the furnace reaches a certain predetermined value, otherwise 181lure of the lining occurs and even explosion liable to take place.

Ударостійкий чавун для молольних тіл

A study of the dynamic strength (impact resistance) of grinding bodies cast from low-chromium cast iron in a multi-seat chill mold depending on the chromium content in the alloy is carried out. As a starting point, cast iron of the following composition was used: carbon – 3,0%, silicon – 1,6%, manganese – 0,4%, sulfur – 0,05%, phosphorus – 0,06%. For the study, several batches of balls with a diameter of 60 mm were cast with different chromium content in cast iron, from 0 to 1%. Cast iron was smelted in a medium-frequency induction furnace, such as IChT, with the main lining on a charge of pure pig iron and steel low-carbon scrap. The temperature of cast iron production was 1500 °C. Liquid cast iron was subjected to alloying with medium carbon ferrochrome. Balls were cast in multi-seat chill molds. When tested for impact resistance, the grinding ball received a striking blow of mass 50 kg, falling from a height of 0,5 m. The frequency of application of dynamic loads was 10 beats per minute. Impact resistance was determined by the average number of impacts sustained by the grinding body prior to destruction. An increase in the impact resistance of ball castings has been established with an increase in the mass fraction of chromium in cast iron up to 1%. Moreover, the greatest increase in dynamic strength is observed with an increase in the mass fraction of chromium from 0,3% to 0,5%. With a further increase in the chromium content, the impact resistance of white low-alloy cast iron increases less noticeably, and in the presence of chromium 0,7-0,8% reaches a maximum. The difference in hardness from the surface (~ 52 HRC) to the center of the ball (~ 42 HRC) is a value of about 10 units. The established impact resistance of grinding bodies made it possible to conclude: when grinding solid rocks with high content of solid quartz, the use of low chromium cast iron as a material for grinding media is the most effective, as in terms of achieve high impact resistance, and to ensure cost-effective performance.

Impurity Removal from Diamond-Wire Cutting Waste by Slag Refining and Electromagnetic Stirring

This paper proposes a method of recycling and purifying silicon from diamond-wire cutting waste by a combined process of slag refining and electromagnetic stirring. A slagging agent of calcium silicate containing barium oxide was added to the diamond-wire cutting waste. Different experimental conditions were carried out for silicon separation and purification. Owing to the difference of affinity between impurity elements and oxygen, the elements with high oxygen affinity combined with oxygen and changed into oxides, which entered into the slag phase. The separation of silicon and slag in the melt was realized through electromagnetic stirring in a medium frequency induction furnace. The experimental results show that this proposed refining method can remove impurities more effectively from diamond-wire cutting waste. It was also found that the mass ratio of slag to silicon has a significant effect on the separation efficiency of silicon.

Experimental Continuous Casting of Nitinol

Commercially available nitinol is currently manufactured using classic casting methods that produce blocks, the processing of which is difficult and time consuming. By continuous casting, wherein molten metal solidifies directly into a semi-finished product, the casting and processing of ingots can be avoided, which saves time and expense. However, no reports on continuous casting of nitinol could be found in the literature. In this work, Φ 12 mm nitinol strands were continuously cast. Using a graphite crucible, smelting of pure Ni and Ti in a medium frequency induction furnace is difficult, because it is hard to prevent a stormy reaction between Ni and Ti and to reach a homogeneous melt without a prolonged long holding time. Using a clay-graphite crucible, the stormy reaction is easily controlled, while effective stirring assures a homogeneous melt within minutes. Strands of nearly equiatomic chemical compositions were obtained with acceptable surface quality. The microstructure of strands containing over 50 at. % Ni, consisted of Ti2Ni and cubic NiTi, whereas the microstructure of strands containing less than 50 at. % Ni consisted of TiNi3 and cubic NiTi. This is consonant with the results of some other authors, and indicates that the eutectoid decomposition NiTi → Ti2Ni + TiNi3 does not take place.

Influence of Austempering Heat Treatment on Ductile Iron

In this present work the influence of austempering heat treatment was studied on ductile iron. Medium frequency induction furnace was used to make casting samples. Austempered Ductile Iron (ADI), which is a relatively new material is produced by the process of austempering heat treatment. ADI material is a very valuable. The properties of ADI are equivalent to forged steel. This study was done to develop Austempered Ductile Iron and to find out the effect of heat treatment temperature. In this study samples were treated, one with higher heat treatment temperature i.e. 370 0C and other in lower range of temperature i.e. 285 oC were used. For austenitizing of samples the furnace temperature was maintained at 900 oC and the samples were heated for one hour. After austenitizing, the samples were dipped in a salt bath at temperatures i.e. 285 oC and 370 oC for one hour. The researcher found encouraging result. Almost double tensile strength was achieved with the same composition of the samples only with the heat treatment at lower temperature.

Comparison of the Microstructure of M2 Steel Fabricated by Continuous Casting and with a Sand Mould

AISI M2 steel was smelted in a 150 kg medium-frequency induction furnace and cast to form round billets with a cross-section diameter of 100 mm via a vertical continuous caster and sand mold. The secondary dendrite arm spacing (λ2), cooling rates, permeability and size and distribution of grains and network carbides of the two billets were studied. The results show that the continuous casting process can effectively decrease the λ2 value, permeability and size of the grains and carbides and improve the distribution of the grains and carbides during solidification. The λ2 values of the billets cast with a sand mold and continuous caster are 37.34 μm and 21.14 μm, respectively, and the cooling rate is 3.6 K·s−1 and 12.0 K·s−1, respectively. The area fractions of carbides at the center of the billets cast with the sand mold and continuous caster are 0.24 and 0.16, respectively, and increase by 27.7% and 25.4%, respectively, compared with their average values. The average grain size of billets cast with the sand mold and continuous caster is 69.4 μm and 50.5 μm, respectively. Compared with the sand mold billet, the grain size at the center of the continuous casting billet is reduced by 25.5%. The relationship between the grain size and cooling rate is presented in this paper.

Effect of holding time, thickness and heat treatment on microstructure and mechanical properties of compacted graphite cast iron

The effect of holding time, thickness and annealing heat treatment on the microstructure and some mechanical properties of compacted graphite iron (CGI) are studied. Samples of CGI are produced in Helwan factory for casting by using GGG 70 as base metal in a medium frequency induction furnace. The mechanical properties (tensile strength, and hardness) of the as-cast and after heat treatment samples are determined and the microstructure of the samples is examined using optical microscope. The results show that the mechanical properties and microstructure of CGI depend on holding time, thickness and annealing heat treatment; it is found that increasing the holding time from 10min to 17min results in lowering the Mg content from 0.031% to 0.021% and as a result lower nodularity was obtained. Lowering the thickness from 20mm to 5mm increases the tendency of dendritic structure as a result of increasing the cooling rate. The annealed samples with mainly ferritic matrix gave the lowest tensile strength and hardness value compared with the as-cast conditions.

Development of digital control system for medium frequency induction furnaces

Traditional medium frequency induction furnace usually adopts analog circuit, which use the theory of PLL to synchronize the drive signal with the induced current signal, so that the upper and lower devices of each phase leg could be gated simultaneously Besides, some problems appear subsequently such as matching debugging difficulty and high failure rate. This paper describes the effect of the burden on the resonant electromagnetic field and resonant frequency through theoretical analysis and magnet field simulation. Based on this, a control and monitoring system designed by digital passive trigger architecture is proposed, phase locking of which is performed according to the frequency of the system itself, fully ensuring that the thyristor will not be simultaneous. In order to improve the stability of the system, this paper optimizes the inverter output control process. At the same time, a friendly human-computer interaction platform is designed, which can achieve distributed data mining, and improve the quality of the product and find the common problems in the product. Finally, the reliability of the control system is verified by experiments.

Investigations on Microstructure and Properties of 16 wt% Cr-3 wt% B-0.6 wt% C-1 wt% Mn-Fe Alloy

In this paper, a wear-resistant alloy with the chemical composition of 16 wt% Cr-3 wt% B-0.6 wt% C-1 wt% Mn-Fe, in which M2B was the antifriction skeleton, was prepared in a medium-frequency induction furnace. The microstructure and mechanical properties were experimentally investigated. The results show that the microstructure of the Fe-Cr-B alloy was composed of lath martensite and clavate, reticular, and clustering borides (M2B). After the thermal treatment, the morphology, chemical composition, and volume fraction of the M2B did not change significantly. Because of the reduction in element saturation, secondary borides M23(B,C)6 precipitated from the matrix, which resulted in a decrease in matrix microhardness. As a result, the bulk hardness and abrasive resistance of the alloy accordingly decreased, and the impact toughness inversely increased. According to the results of XRD, electronic probe microanalyzer (EPMA), and TEM, the chemical formula of M2B was FeCr0.89Mn0.14(B,C), which resulted in a body-centered tetragonal (BCT) structure. The chemical formula of the M23(B,C)6 was Fe17.97Cr4.13Mn1.14 (B,C)6, which resulted in a face-centered cubic (FCC) structure.

A study on the microstructures and three–body abrasive wear behaviors of Fe–B alloy under different Fe2B boride orientation

PurposeThe directional solidification Fe-B alloy was prepared. The microstructures and three-body abrasive wear behaviors of directional solidification alloy were investigated.Design/methodology/approachFe-B alloy was melted in medium frequency induction furnace. The hardness was measured on HRS-150 Rockwell-hardness tester and HXD-1000TMC tester. The wear characteristic of the alloy was examined with a block-on-ring geometry. The worn surface of the alloy was investigated by scanning electron microscopy and laser scanning microscopy.FindingsThe wear weight loss and worn surface roughness increase with the increasing contact load in wear tests. When the worn surface is perpendicular to the boride growth direction, the highest hardness plane of the boride can resist abrasive effectively under the surrounding and supporting of the martensite matrix.Originality/valueThe relation between boride growth direction and wear direction will cause different boride breaking tendency and wear weight loss.

Pilot-Scale Test of Dephosphorization in Steelmaking Using Red Mud-Based Flux

Bayer red mud is characterized by its highly oxidizing nature and high alkalinity. It can act as an ideal flux and dephosphorizer in steelmaking. In this study, pilot-scale tests applying the Bayer red mud-based flux in steelmaking have been conducted in a 200-kg, medium-frequency induction furnace. Good slag fluidity and no rephosphorization phenomena are observed. High dephosphorization rates (~90%) and low final [P] (<0.02%) are obtained in the situation of high [C] of 2.0–3.0%, which are of great importance for the production of clean steel. The P2O5 content in the P-rich phase in the red mud-based slag can reach as high as 34.05 wt.%, far higher than the 6.73 wt.% in ordinary industrial slag. This suggests that the Al2O3, TiO2 in Bayer red mud can enhance the solid solubility of phosphorus in the P-rich phase. The data obtained are important for promoting the large-scale application of red mud in steelmaking.