Influence Of Electromagnetic Stirring Research Articles

Influence of Electromagnetic Stirring During the Solidification on the Structure and Magnetic Properties of 2% Si Electrical Steel

Influence of Electromagnetic Stirring During the Solidification on the Structure and Magnetic Properties of 2% Si Electrical Steel

A review of electromagnetic stirring on solidification characteristics of molten metal in continuous casting

The solidification of molten metal represents a pivotal phase in the preparation and shaping of metallic materials. Continuous casting, as a crucial juncture in the solidification of molten metal, occupies a position of paramount significance. Nevertheless, during the process of continuous casting, challenges emerge, including uneven temperature field distribution, non-uniform solidification microstructures, and the presence of impurities, leading to defects such as segregation and shrinkage in the castings. Researchers have devoted decades to addressing these issues, culminating in the discovery that the application of electromagnetic stirring during continuous casting can expedite the flow of molten metal, enhance solute diffusion, thereby achieving uniform temperature and flow field distributions, refining solidification microstructures, and ameliorating macrosegregation, among other benefits. This article provides an overview of the recent research achievements and advancements in the utilization of electromagnetic stirring during the continuous casting process. It primarily elucidates various stirring devices commonly employed in continuous casting and expounds upon the influence of electromagnetic stirring on solidification characteristics. And the current problems and future development trends in the application of electromagnetic stirring were discussed.

Effect of casting speed on solidification and inclusion motions in bloom mold caster under the influence of in-mold electromagnetic stirring

PurposeThe purpose of this article is to numerically investigate the effect of casting speed on the fluid flow, solidification and inclusion motion under the influence of electromagnetic stirring (EMS) in the bloom caster mold with bifurcated submerged entry nozzle (SEN).Design/methodology/approachThe electromagnetic field obtained by solving Maxwell’s equation is coupled with the fluid flow, solidification and discrete phase model using the in-house user-defined functions. An enthalpy porosity approach and Lagrangian approach are applied for the solidification analysis and non-metallic inclusions motion tracking, respectively.FindingsInvestigation shows that the casting speed and EMS significantly affect the steel flow, solidification and inclusion behavior inside the mold. Investigations are being conducted into the complex interplay between the induced flow and the SEN’s inertial impinging jet. In low and medium casting speeds, the application of EMS significantly increases the inclusion removal rate. Inclusion removal is studied for its different size and density and further effect of EMS is also reported on cluster formation and distribution of inclusion in the domain.Practical implicationsThe model may be used to optimize the process parameter (casting speed and EMS) to improve the casting quality of steel by removing the impurities.Originality/valueThe effect of casting speed on the solidification and inclusion behavior under the influence of time-varying EMS in bloom caster mold with bifurcated nozzle has not been investigated yet. The findings may assist the steelmakers in improving the casting quality.

Segregation behavior and precipitated phases of super-austenitic stainless steel influenced by electromagnetic stirring

Super austenitic stainless steel was prepared by vacuum non-consumable arc melting furnace. The influence of electromagnetic stirring on segregation behavior and the precipitates of super-austenitic stainless steel was investigated via a combined thermodynamic calculation and an experimental characterization approach. The σ phase is the main precipitation phase in super austenitic stainless steel, which has been proved by Thermo-Calc software and experimental characterization. Electromagnetic stirring significantly reduces the dendrite spacing and refines the solidification microstructure. In super-austenitic stainless steel, Cr, Mn, and Mo are positively segregated, while Ni and Fe are negatively segregated. Si and Cu have no obvious segregation. The segregation coefficient (K) shows that the segregation of Mo element is the most serious. Compared with no electromagnetic stirring, the segregation of elements in the electromagnetic stirring sample is significantly weakened.

Influence of EMS on Asymmetric Flow with Different SEN Clogging Rates in a Slab Continuous Casting Mold

Submerged entry nozzle (SEN) clogging is a troublesome phenomenon in the continuous casting process that can induce the asymmetric mold flow, and thus, lowering the steel product quality. In this paper, a mathematical model coupling the electromagnetic and flow fields, was developed to investigate the influence of the SEN clogging rate on the flow field and the influence of electromagnetic stirring (EMS) on the asymmetric mold flow. Slag entrapment index Rc was introduced to quantify the possibility of slag entrapment, and symmetric index S was introduced to quantify the symmetry of the flow field. The results show that as the SEN clogging rate increased, the slag entrapment index Rc increased, while the symmetric index S decreased. EMS can greatly improve the symmetry of the flow field with SEN clogging, but it cannot remove the asymmetric phenomenon completely because the stirring intensity should be controlled below the safe level to avoid slag entrapment.

Numerical and experimental investigation of thermo-fluid flow and element transport in electromagnetic stirring enhanced wire feed laser beam welding

The introduction of electromagnetic stirring to laser beam welding can bring several beneficial effects e.g. element homogenization and grain refinement. However, the underlying physics has not been fully explored due to the absence of quantitative data of heat and mass transfer in the molten pool. In this paper, the influence of electromagnetic stirring on the thermo-fluid flow and element transport in the wire feed laser beam welding is studied numerically and experimentally. A three-dimensional transient heat transfer and fluid flow model coupled with dynamic keyhole, magnetic induction and element transport is developed for the first time. The results suggest that the Lorentz force produced by an oscillating magnetic field and its induced eddy current shows an important influence on the thermo-fluid flow and the keyhole stability. The melt flow velocity is increased by the electromagnetic stirring at the rear and lower regions of molten pool. The keyhole collapses more frequently at the upper part. The additional elements from the filler wire are significantly homogenized because of the enhanced forward and downward flow. The model is well verified by fusion line shape, high-speed images of molten pool and measured element distribution. This work provides a deeper understanding of the transport phenomena in the laser beam welding with magnetic field.

Solution of three-dimensional temperature and turbulent velocity field in continuously cast steel billets with electromagnetic stirring by a meshless method

This paper demonstrates the development of meshless Local Radial Basis Function Collocation Method (LRBFCM) for solution of three dimensional (3D) turbulent molten steel flow and solidification under the influence of electromagnetic stirring (EMS) and its application to continuous casting process of steel billets. A mixture continuum approach is used to formulate the coupled set of macroscopic equations for mass, momentum, energy, turbulent kinetic energy, and dissipation rate in Cartesian coordinates. The mushy zone is treated as a Darcy porous media. The explicit Chorin fractional step method is used to resolve the pressure-velocity coupling. The LRBFCM uses explicit time discretization and spatial discretization with shape-adaptive multiquadrics radial basis functions collocation on non-uniform seven-noded influence domains, and displacement-adaptive upwind scheme. The Lorentz force due to EMS is provided by a one-way coupling by Elmer software. The advantages of the meshless method are trivial adaptation of the nodal densities, simple upgrade to 3D from previous two-dimensional models, and high accuracy. A study on the influence of changing the EMS parameters on the calculated temperature and velocity fields is performed. The paper confirms the ability of LRBFCM meshless solution of a realistic 3D multiphysics industrial problem with complicated swirling flow pattern.

Influence of electromagnetic stirring on microstructure and wear resistance of plasma arc deposited shape memory alloy

In order to obtain metallurgical shape memory alloy with a better quality, electro-magnetic stirring (EMS) technology is selected as an aiding method during plasma arc deposition (PAD) process. In this work, Ti51Ni49 alloys were successfully produced by EMS-assisted PAD technology. Influence of EMS on the microstructure, phase transformation behavior, micro-hardness and wear resistance of PAD TiNi alloy have been systematically investigated. The PAD TiNi alloy is composed of TiNi coarse columnar dendrites with a certain number of Ti2Ni phases distributed in the inter-dendritic regions. Under the action of EMS, TiNi coarse columnar dendrites transform into fine non-dendrites or spheroid grains and the homogeneity of microstructures improves significantly. The implementation of EMS during PAD do not change the path of phase transformation, but improve the degree of phase transformations and reduce the transformation temperatures of PAD TiNi alloy. The EMS-PAD TiNi alloy possesses better dry wear resistance than the PAD TiNi alloy, which can be attributed to the higher degree of pseudo-elasticity of TiNi phases and strengthening of Ti2Ni phases.

Investigations of fluid flow effects on dendritic solidification: Consequences on fragmentation, macrosegregation and the influence of electromagnetic stirring

Solidification experiments and numerical simulations have been performed to improve the understanding of the complex interrelation between melt flow and the formation of dendritic structures during solidification of Al-Cu and Ga-In alloys. Melt flow induces various effects on grain morphology primarily caused by convective transport of solute, such as a facilitation of the growth of primary trunks or lateral branches, dendrite remelting, fragmentation or freckle formation depending on the dendrite orientation, the flow direction and intensity. Within this project special interest was focused on fragmentation and segregation phenomena. Natural convection is caused by density variations within the solidifying alloys. Forced convection was produced by electromagnetic stirring. X-ray radioscopy was applied as a powerful tool for the visualization of dendritic growth and coarsening.

Primary Structure and Mechanical Properties of AlSi2 Alloy Continuous Ingots

AbstractThe paper presents the research results of horizontal continuous casting of ingots of aluminium alloy containing 2% wt. silicon (AlSi2). Together with the casting velocity (velocity of ingot movement) we considered the influence of electromagnetic stirring in the area of the continuous casting mould on refinement of the ingot’s primary structure and their selected mechanical properties, i.e. tensile strength, yield strength, hardness and elongation. The effect of primary structure refinement and mechanical properties obtained by electromagnetic stirring was compared with refinement obtained by using traditional inoculation, which consists in introducing additives, i.e. Ti, B and Sr, to the metal bath. On the basis of the obtained results we confirmed that inoculation done by electromagnetic stirring in the range of the continuous casting mould guarantees improved mechanical properties and also decreases the negative influence of casting velocity, thus increasing the structure of AlSi2 continuous ingots.

Structure and Usable Properties of Aluminum Continuous Ingots

Abstract In paper is presented results of studies concerning ingot of Al with a purity of 99.5% cast with use of stand of horizontal continuous casting. Mainly together with casting velocity was considered influence of electromagnetic stirrer, which was placed in continuous casting mould on refinement of ingots structure and theirs usability to plastic deformation. Effect of structure refinement and usability to plastic deformation obtained by influence of electromagnetic stirring was compared with refinement obtained by use of traditional inoculation, which consists in introducing of additives i.e. Ti and B to metal bath. On the basis of obtained results was affirmed that inoculation realized by electromagnetic stirring in range of continuous casting mould guarantees improvement in structure refinement and usability to rolling of pure Al continuous ingots.

The Stand of Horizontal Continuous Casting of Al and its Alloys

Abstract In paper is presented idea of construction and influence of selected parts of stand of horizontal continuous casting on quality of pure Al and AlSi2 alloy ingots. The main parts of the made stand belong to induction furnace, which is also tundish, water cooled continuous casting mould, system of recooling, system of continuous ingot drawing and cutting. Mainly was considered influence of electromagnetic stirrer, which was placed in continuous casting mould on refinement of ingots structure. Effect of structure refinement obtained by influence of electromagnetic stirring was compared with refinement obtained by use of traditional inoculation, which consists in introducing of additives i.e. Ti and B to metal bath. The results of studies show possibility of effective refinement of Al and AlSi2 alloy primary structure, only with use of horizontal electromagnetic field and without necessity of application of inoculants. This method of inoculation is important, because inoculants decrease the degree of purity and electrical conductivity of pure aluminum and moreover are reason of point cracks formation during rolling of ingots.

The Influence of Electromagnetic Stirring on Primary Structure of Pure Al and Al-Si Alloy

In paper problem concerning inoculation of primary structure of Al with purity of 99,5% and 99,8% and AlSi2 alloy, which is realized mainly by intensification of liquid metal movement in mould is presented. In aim of realization of forced movement during the crystallization of liquid metal was used horizontal electromagnetic field produced by the induction coil (stirrer) supplied by current with elevated frequency. The degree of structure refinement was represented mainly by equiaxed crystals zone content on transverse section of ingot and average area of macro-grain in this zone. Effect of structure refinement obtained by influence of electromagnetic stirring was compared with refinement obtained by use of traditional inoculation, which consists in introducing of additives i.e. titanium, boron and strontium to metal bath. The results of studies and their analysis show possibility of effective refinement of pure Al and Al-Si alloy primary structure, only with use of horizontal electromagnetic field and without necessity of application of inoculants such a Ti and B. This method of inoculation is important, because inoculants decrease the degree of purity and electrical conductivity of pure Al. Moreover inoculants are reason of point cracks formation during rolling of ingots.

Influence of electromagnetic stirring on transport phenomena in round billet continuous casting mould and macrostructure of high carbon steel billet

The characteristics of magnetic field, flow field, temperature profile and inclusion trajectories in a round billet continuous casting mould with electromagnetic stirring (M-EMS) were numerically simulated. An industrial plant trial was conducted to verify the magnetic field characteristics and investigate the influence of M-EMS on the solidification macrostructure of high carbon steel. The results indicate that the predicted magnetic field was in good agreement with the measured data, and the velocity patterns, temperature, inclusion trajectory distributions and macrostructure of steel are significantly modified using M-EMS during casting.

Effect of Vertical Electromagnetic Stirring on the Grain Refinement of A356 Aluminum Alloy Inoculated by Al-5Ti-B

In this paper, the influence of electromagnetic stirring on the grain size of A356 alloy inoculated by Al-5Ti-B was investigated. It is found that when stirring is applied at the same time with Al-5Ti-B, the inoculation effect will be disabled. X-ray determination and SEM observation show that stirring hinders the deposition of TiB2 particles; consequently hinder the formation of TiAl3 particles, which were proved to be the nucleus of primary α aluminum phase. If the stirring time is short, the grain size will be abnormally coarse. This experiment also confirms that the grain refinement of rheocasting is caused by dendrite fracture instead of modified nucleation.

Grain refinement induced by electromagnetic stirring: A dendrite fragmentation criterion

The influence of electromagnetic stirring (EMS) on grain refinement has been studied for two copper-base alloys (Cu-1 wt pct Ni-1 wt pct Pb-0.2 wt pct P and Cu-4 wt pct Zn-4 wt pct Sn-4 wt pct Pb) solidified in a Bridgman furnace. Metallographic inspection of the specimens, temperature measurements during solidification, and numerical simulations performed with CALCOSOFT revealed that the efficiency of EMS is strongly dependent upon the penetration of the liquid in the mushy zone and therefore upon the position of the convection vortices with respect to the liquidus front. In particular, the low-concentration alloy could be grain refined only at high power and when the coil was moved close to the liquidus front. These results were analyzed on the basis of a dendrite fragmentation criterion similar to Flemings’ criterion for local remelting of the mushy zone. Considering that the component of the fluid flow velocity along the thermal gradient, \(u_{l,G} = \frac{{u_e \cdot \nabla T}}{{\left\| {\nabla T} \right\|}}\), must be larger than the casting speed, Vc, dendrite fragmentation occurs if $$C_R \approx \frac{1}{{V_c }}\frac{K}{{g_l \cdot \mu }}\frac{{B_0^2 }}{{\mu _0 d_{ind} }} > 1$$ at some depth within the mushy zone where dendrite arms are sufficiently developed, typically 8 λ2, where λ2 is the final secondary dendrite arm spacing, K is the permeability of the mushy zone, gl is the volume fraction of liquid, μ is the dynamic viscosity, B0 is the magnetic field, μ0 is the permeability of vacuum, and dind is the distance between the inductor and the liquidus front.

Electromagnetic Stirring and the Cleanness of AlTiB Master Alloys

The influence of electromagnetic stirring on the cleanness of AlTiB master alloys has been investigated. It is found that the slag can be deprived from AlTiB master alloys by electromagnetic stirring, and the stirring effect of A.C.magnetic field is better than that of D.C. magnetic field. When the A.C.magnetic intensity is 0.24 T, the slag are deprived perfectly after the melt been stirred for three minutes. The electromagnetic stirring can improve the refining effect of AlTiB master alloys. The principle of depriving slag by electromagnetic stirring has also been elementarily investigated. It is found that the magnetic field not only causes the revolvement of melt, but also produces the secondary flow 1 cm away from the wall of crucible. The secondary flow is the main reason to cause depriving slag.

The influence of electromagnetic stirring on Al-Ti-B master alloys

Electromagnetic stirring can improve the refining effect of Al-Ti-B master alloys by removing slag from the melt. When alternating-current magnetic intensity is 2,400 G, slag is removed after the melt has been stirred for three minutes. The magnetic field not only causes the melt to circulate, but also produces the secondary flow 1 cm away from the crucible wall that is the primary cause of slag removal. An alternating-current magnetic field removes slag more efficiently than a direct-current magnetic field.

連鋳々片負偏析におよぼす鋳型内電磁撹絆の影響

連鋳々片負偏析におよぼす鋳型内電磁撹絆の影響

軟鋼サブマージアーク溶接金属の機械的性質におよぼす磁気撹拌の影響

A few reports have been made on the influence of electromagnetic stirring on weld zone, from the point of minimization of crystal grain and acceleration of blowhole decrease, in the case of TIG and MIG welding for titanium alloy or aluminium alloy.But the application for Submerged-arc welding has not been experimented. Therefore, in the former report, the authors investigated, how the electromagnetic stirring made influence on its bead shape, penetration and solidification structure of D.C.submerged-arc welding of mild steel. From this study the authors made it clear that the shape of penetration showed very peculiar change and that the primary crystals of weld metal were minimized.In this cotinuous report, the authors investigted how electromagnetic stirring hardness distribution and notch toughness of Submerge-arcd weld zone changed.The authors measured the hardness distribution by micro-Vickers Hardness tester, and the notch toughness by V-notch Charpy impact test. From these studies the authors have found out the following results.1) The hardness increases by electromagnetic stirring.2) As to the notch toughness, the authors made the transition curves of absorbed energy and fracture phase from the impact test, and from them, obtained the transition temperature of both 15ft-lb and fracture phase.As the result it became clear that both of the transition temperatures moved to the lower temperature side by 20 degrees C. The author also made the micro observation of fracture phases of impact test pieces with electron microscope and considered the changes of shape of the destructive phase caused by electromagentic stirring.