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By B. Farouk, Y. G. Kim, D. Apelian

"Continuous strip casting has received considerable attention in recent years due to its economic advantages with increased energy savings and the elimination of intermediate processing steps. A promising concept in strip casting is the twin-belt (Hazelett) process which incorporates two cooled continuously moving thin metal belts wrapped around pulleys which tension and drive the belts at a predetermined speed. Molten metal is introduced at the entry end of the caster through a tundish and feeding nozzle into the mold. The twin-belt process has been successfully used with non-ferrous metals such as aluminum, copper and brass, and is a prime candidate for strip casting of ferrous materials. A numerical model has been developed which predicts the interface locations, the temperature fields in the solid and liquid regions of the cast and the velocity fields of the liquid metal at the entrance region of the twin-belt caster. The process variables considered are the velocity and cooling conditions of the belt and the nozzle shape. A body fitted coordinate system is used to track the front locations and to solve .the Navier-Stokes equations in the liquid region. Results obtained can help design efficient casters for thin strip steel castings. The development of the numerical model is presented, and sample results are discussed. I. IntroductionContinuous strip casting of steel has attracted world-wide concerns in recent years due to its economic advantages with increased energy savings and the elimination of intermediate processing steps. New methods of thin strip casting of steel are developing. One of the promising concepts is the Hazelett process, which is being used in nonferrous applications. The process incorporates two continuously moving, intensely cooled, thin metal belts. Metal blocks linked together are sandwiched between the moving belts and form moving side mold walls.In this work, the freezing front position, the temperature field and the liquid region flow field will be analyzed for the strip casting of metal using the twin belt caster (the Hazelett process). Up to now almost all theoretical analyses undertaken of the continuous casting of metal [1-3] have used a heat conduction equation, assuming slug flow in the liquid region. The effect of convection in the liquid pool during continuous casting were first investigated by Szekely and Stanek [4]. They considered potential flow between the feed metal orifice and the liquidus front, and slug flow in the mushy and solid regions of a vertical static continuous casting process for steel. Viscous effects and natural convection affects were not included Kroeger and Ostrach [5] studied the effect of natural convection flow in the liquid pool during solidification for a pure metal."

Jan 1, 1986

By Alessandro Blasi, Massimo Morgana, Corradino Sposato, Pietro Garzone, Giuseppe Devincenzis

The rare earth elements are essential for a diverse and expanding array of high-technology applications, which constitute an important part of the industrial economy of the 21st century. As a matter of fact, rare earth has been listed in the category of strategic elements in many countries becoming a core business for international research. Experimental tests have been carried out on a bench scale battery of mixer settler composed of 24 stages, each one with a volume of 150 ml. These trials have been performed at room temperature checked by a micro-climatic control system. The battery was setted in two sections: extraction and scrubbing section. Rare earths concentrations were obtained by ICP-OES analysis made on aqueous phase and on the stripped from organic phase. We obtained a complete separation of light rare earth (La, Ce, Pr, Nd) in two sub-groups: La/Ce and Pr/Nd.

Jan 1, 2014

By Truan-Sheng Lui, Li-Hui Chen, Fei-Yi Hung, Cheng-Yi Chen

"This research used the austempering heat treatment on the SCM435 thin specimen with a type of double loop and obtained the Cr-Mo bainite structure, and then we could further investigate the mechanical properties of SCM435 bainite structure. Experimental data showed the stability of the mechanical properties of specimen with austempering temperature 830°C for 25 minutes was better than that of 15 minutes. The size of austenite grain affected the strength of thin specimen. After austempering at 830°C-25minutes and salt bath at 290°C, the stability of UTS was better than that of salt bath at 310°C and 330°C. The average hardness of all specimens was about more than HRA70. The specimen with austempering at 830°C-25minutes and salt bath at 290°C-30minutes had bigger grain size of austenite and retained y, it also had higher hardness and strength toughness. So, its stability was improved for tensile strength comparing with traditional tempered martensite process.IntroductionSCM435 is a Cr-Mo steel with high strength and high hardness properties, and it has been widely used in machine parts, shafts, gears and strength screw products [1-3]. However, this system often has lower reliability due to the brittleness of high-temperature tempering and quenching inequality. Considering the austempering heat treatment can obtain the uniform bainite structure to improve the temper brittleness, and the austempering heat treatment is a continuous process that it also has efficiency and uniformity. For the thin plate specimens, the mechanical properties of the bainite structure are better than traditional martempering structures."

Jan 1, 2013

By Dianyuan Dang, Guihong Han, Wenjuan Wang, Tao Jiang, Yanfang Huang

In this study reduction kinetics and swelling behaviors in "two-step process” were investigated by weight-loss technique and visualizing physical changes of pellet. Results showed that reduction degree (r) increased with increasing temperature and time. According to the dynamic calculation, when reduction temperature was lower than 1000°C the reduction process was controlled by chemical reaction with apparent activation energy of 72.27 kJ/mol. When reduction temperature was higher than 1000 , the equation of t/[1-(1-r)1/3] against [1+2(1-r)-3(1-r)2/3]/[1-(1-r)1/3] followed straight lines, demonstrating that reduction was mixed-controlled. Swelling experiments indicated that the maximum swelling index increased with the increase of reduction temperature and CO content.

Jan 1, 2016

By Noriaki Kurita, Norihiko Fulcatsu, Teruo Ohashi

"An electrochemical sensing device for hydrogen in molten metal has now been available owing to the development of the proton conducting solid electrolyte made of ceramics of metal oxide. The structure of the sensor and the theoretical limitations of its applications are discussed based on the electrochemical properties of the electrolyte used. The practical performance of the sensor is reviewed from the results of test measurements at the plants of aluminum and copper melting industries. The effectiveness of the sensor to the process control of continuous casting of copper is also discussed.IntroductionSince the in-line monitoring of the amount of oxygen dissolved in molten metal was realized by using the oxygen concentration cell based on zirconia solid electrolyte a similar method has been expected to be developed for sensing of hydrogen, which is a very important element of gas species in liquid metals, especially, in aluminum and copper. In 1981; Iwahara and coworkers found the dominant proton conduction at a high temperature in some perovskite-type oxide (1). Since then, the effort has been made to apply this proton conducting material as the electrolyte of the hydrogen concentration cell for high temperature use. The hydrogen sensor for liquid aluminum of this kind was first produced in 1991 (2) and released commercially from TYK Co., Ltd. Recently, we have developed the mother one usable at higher temperature such as copper and silver melting processes (3). In this note we discuss their structure, design and applicable limitations based on the electrochemical properties of this new type electrolyte. The performance of the sensor and benefit to use it to control the melting process is also discussed"

Jan 1, 2000

By David G. Dixon

A mathematical model is derived in dimensionless form which simulates the effluent concentration response of reagents from spent heaps under both fresh and recycled water rinsing. The model is based on dispersion from isochoric pathways distributed in length and cross-section, oriented normal to convection channels in ideal plug flow. The effects of heap height, rinsate flow, and initial reagent concentration are examined. It is shown that the rinsing cycle undergoes a distinct shift between fast and slow rinsing at a certain time depending on the amount of stagnant solution in the heap, and the distribution of dispersion pathways. Results of preliminary column rinsing tests on both agglomerated and unagglomerated ores are presented which partially validate the model.

Jan 1, 1994

By Nagy El-Kaddah

"One of the emerging technologies for the production of ultra-clean metals is electromagnetic filtration. The theory and the mechanism of electromagnetic separation of inclusions from molten metal are briefly reviewed along with basic electromagnetic separation systems. This paper focuses on inclusion removal in the induced current separators, with specific reference to a new separator developed at the University of Alabama. A simple analytical model is presented for the analysis of particle separation in such a system. The role of the applied magnetic field on inclusion removal will be discussed. It is shown that particle velocity increases exponentially with increasing magnetic field strength. At moderate field strengths, the velocity of 50 to 100 u. inclusions· are an order of magnitude larger than those achieved by buoyancy. The separator developed at the University of Alabama is described together with experimental results of laboratory and large scale experiments on purification of molten aluminum. These results demonstrate the capability of the system for producing super-clean metals.IntroductionThe nature of extraction, refining and processing of metals is such that oxides and other non-metallic particles will always be present. This is due to the highly reactive nature of metals with oxygen and other non-metallic elements. The presence of these type inclusions in metals, even in minute amounts, can seriously flaw the reliability and performance of the final product. They not only reduce the strength and the stiffness of the metal/1/, they are the reason behind many of manufacturing defects such as porosity in castings, surface and internal cracks in continuously cast ingots and rolled products, etc., which act to cause premature failure of manufactured parts. In fact, for critical applications such as turbine blades, there is virtually no tolerance for inclusions above ten microns in size /2/. Therefore, removal of inclusions from the liquid metal is an essential processing step.The demand for cleaner metals has brought major changes in the technology and practice of metal refining and casting. Inclusion removal from the melt is currently achieved by passing the melt through a series of melt treatment systems, including induction stirring furnaces, argon-stirred ladle, and ceramic foam and deep-bed filters /3,4/. These systems are generally capable of removing all inclusion particles above 50 microns in diameter, which meets current cleanliness requirements for most applications. However, they may not be able to meet the projected cleanliness levels for critical applications due to kinetic and operational limitations of these systems in removing smaller particles /5/."

Jan 1, 1996

By J. R. Bhamidipati, Nagy EI-Kaddah

"Over the years, mathematical modeling has been established as a viable tool for design and analysis of melting and solidification processes. Modeling of electromagnetic casting and melting systems involves three coupled problems -- determination of the containment field, the shape of the meniscus, and the temperature field -- which have to be solved simultaneously. One of the difficulties in numerical simulation of these systems is in defining and gridding the solution domain as the meniscus shape of the liquid region is not known a priori. This paper describes a methodology for solving these coupled problems in a two-dimensional electromagnetic containment field. This method is based on the solution of the electromagnetic, free surface dynamic, and heat transfer equations in a fixed domain in computational space by mapping the physical space into an invariant computational space during the search for the equilibrium shape using a variable non-orthogonal coordinate transformation. This approach, also, eliminates the need for regridding the liquid and solid regions during phase change. This methodology is demonstrated for two electromagnetic confinement systems -- the Magnetic Suspension Melting process and the electromagnetic casting of aluminum. The model predictions are in good agreement with available data for these systems. It is suggested that the methodology presented here is likely to provide a useful tool in the design, analysis, and optimization of electromagnetic confinement systems. IntroductionDuring the past decade, mathematical modeling has emerged as a viable tool for the design, analysis, and optimization of casting and melting processes /1-2/. It is generally recognized that the usefulness of modeling to study the interplay between the various process parameters without resorting to extensive experimentation relies heavily on accurate representation of the physical phenomena in these systems. In modeling electromagnetic confinement casting and melting systems, it is important that the model address all aspects of electromagnetic field interaction with the metal, if accurate predictions are to be obtained /3/. The electromagnetic field affects the heat transfer phenomena primarily through joule heating. In addition, the electromagnetic forces play a key role in heat redistribution in the molten pool via melt stirring, and, in confinement systems, support the molten metal pool."

Jan 1, 1994

By Yuanbo Zhang, Zhixiong You, Li Qin, Guanghui Li, Tao Jiang

Low-grade manganese oxide ore is generally characterized by high iron content. In this work, sulfidation roasting of an iron-rich manganese oxide ore with elemental sulfur was characterized. The experimental results indicated that manganese dioxide can be selectively reduced over iron oxide by using elemental sulfur. The manganese phases in roasted product included low-valence manganese oxide, manganese sulfide and manganese sulfate, while those of iron mainly depended on the sulfur addition. Iron oxide would only be reduced or sulfidized at larger sulfur additions. The effect of roasting temperature and S/Mn mole ratio on the phase transformations was also investigated; extractions of Mn/Fe by sulfuric acid were evaluated. An extraction of Mn greater than 95% was obtained while that of Fe was controlled less than 10% under the optimal conditions.

Jan 1, 2016

By Claudio Parra De Lazzari

The determination of the governing step of the deoxidation rate and the effects of the hydrogen content of the mixtures (C), the diameter of the delivery orifice (4) and the Reynolds number of the orifice (Re.) on the product Av kjg were investigated. A,, is the total surface area of the interface between the bubbles and the melt and kjg is the mass transfer coefficient in the gas phase. The design of the experiments was based on a two level statistically fractionated, factorial planning. Oxygen in the melt was measured as a function of time. It was found that the governing step of the deoxidation rate was the transport of hydrogen in the gaseous phase and that {Ay kjg} increases with C, {o} and Reo.

Jan 1, 1997

By T. -M. Guo, M. J. Braun

"This paper presents an experimental and numerical study of melt flow near the solid-liquid interface and its effect on the interface curvature in a horizontal unidirectional solidification system with succinonitrile. Melt flow is introduced by increasing the ampoule channel thickness. Visualization techniques are employed to observe the flow field and the solid-liquid interface curvature. A numerical model is also developed to simulate the heat transfer, melt flow and phase change in the system. Quantitative information on the flow and temperature fields is generated. A good agreement is achieved between the experimental observations and model predictions. The results could be used for the study of the effect of the melt flow on interface morphology during solidification.IntroductionClassic unidirectional solidification experiments of transparent alloys are conducted with thin film samples sandwiched between two glass slides to investigate the development of interface morphology during solidification [1]. Samples with small channel thickness are usually used to suppress any melt flow due to natural convection and solidification in the channel would then be in the diffusive regime so that the solidification theory can be significantly simplified [2, 3]. Effects of melt flow, in particular due to natural convection, on solidification have also been studied extensively in those systems with large geometrical dimensions [4-6]. These studies indicate a strong effect of the melt flow on interface curvature during solidification [5, 6]. Only limited efforts were made to address the effect of the melt flow on interface morphology in horizontal unidirectional solidification, in particular for the cases when the channel thickness is not thin enough to suppress completely the natural convection [7]."

Jan 1, 2004

By Toshihide Takenaka

The management of radioactivated stainless steel from a terminated nuclear reactor will become an important subject in the near future. The separation of the elements in stainless steel should be effective to reduce the management labor. In this study, the separation of the elements in stainless steel by an electrorefining tcchnique was investigated in an aqueous solution. The electrochemical reactions of the elements in stainless steel werc studied by voltammetry and potentio-static electrolysis was carried out. A stainless steel anode was dissolved electro-chcmically with good anodic current etliciency in a chloride solution. The residue, where Ni was concentrated, was found on the anode after electrolysis. The electrodeposit in a stainless steel cathode consisted mainly of Fe and Cr and the Ni content in it was less than 0.5wt% under suitable condition. It is concluded that an electrorefining technique is effective for the separation of the elements in stainless steel.

Jan 1, 2003

By W. L. Cornell

Bulk sulfide concentrate produced from Missouri Pb ore concentrator tailings must be reground to liberate sulfide values for subsequent sepa-ration. Studies to determine grinding parameters for optimum liberation were carried out using optical microscopy coupled with image analysis. The major sulfide phases present in the ground mineral particulates are marca-site, pyrite, sphalerite, galena, chalcopyrite, siegenite. and bravoite. Results showed that the base metal minerals were liberated by grinding to 74 micrometers (200 mesh), but the siegenite and bravoite required grinding to 20 micrometers or less to achieve liberation. Both the experimental method and results are presented.

Jan 1, 1987

By Marco Olper

After two years of extensive research a new and innovative modification to the CX-EW process has been exploited. This process, called CX-EWS, avoids completely all the critical aspects of the previous process which affected the cost of the energy, of the chemicals and of The maintenance of the insoluble anodes. All these benefits reflect a saving of about 30% of The operating costs compared to the present traditional production and allow for a total operating costs of less than 6.5 cts/lb. lead (net of raw material cost). With this new technology it is allowed for the first time the treatment in the same plant facilities of both primary lead sulphide concentrate and spent batteries. The paper describes the technical and economical aspect of the new process with a feasibility study for 150,000 t/y spent battery facility throughput.

Jan 1, 1995

By C. M. Wai

"Metal species in solid and liquid materials can be extracted by supercritical carbon dioxide containing a suitable ligand. This in situ che1ation-supercritical fluid extraction technique offers several advantages over conventional solvent extraction including minimization of organic liquid waste generation and exposure of personnel to organic vapors. One unique feature of this technique is that metal species can be removed from solid materials directly using supercritical carbon dioxide as a solvent. Several ligand systems including dithiocarbamates, B-diketones, organophosphorus reagents, and macrocyclic compounds have been tested for metal extraction in supercritical carbon dioxide. This novel extraction technique may have important applications for metal recovery and mineral processing.IntroductionSupercritical fluid extraction (SFE) offers several advantages over conventional solvent extraction including the minimization of organic liquid waste generation and exposure of personnel to organic vapors.[1] The high diffusivity, low viscosity, and T-P dependence of solvent strength are some attractive properties which make supercritical fluids excellent candidates for extraction and recovery of organic compounds from solid materials [2] Carbon dioxide is a gas of choice for SFE because of its moderate critical constants (Tc = 31 °·C and Pc = 73 atm), inertness, and availability in purified form. After extraction, the fluid phase is depressurized to separate organic solutes from CO2 gas and the gas can be recycled for repeated use. The SFE technology has been applied to industrial scale operations such as the preparation of decaffeinated coffee and hop extracts."

Jan 1, 1996

By J. P. Gu, C. Beckermann

"Melt convection and macrosegregation in casting of a large steel ingot is numerically simulated. The simulation is based on a previously developed model for multicomponent steel solidification with melt convection, and involves the solution of fully coupled conservation equations for the transport phenomena in the liquid, mush, and solid. Heat transfer in the mold and insulation materials, as well as the formation of a shrinkage cavity at the top are taken into account. The numerical results show the evolution of the temperature, melt velocity, and species concentration fields during solidification. The predicted variation of the macrosegregation of carbon and sulfur along the vertical centerline is compared with measurements from an industrial steel ingot that was sectioned and analyzed. Although generally good agreement is obtained, the neglect of sedimentation of free equiaxed grains prevents the prediction of the zone of negative macrosegregation observed in the lower part of the ingot. It is also shown that the inclusion of the shrinkage cavity at the top is important in obtaining good agreement between the predictions and measurements.IntroductionMacrosegregation in large steel ingots is one of the most well-known and now classical problems in the field of solidification and casting [1]. Commonly found macrosegregation patterns in steel ingots are a positively segregated zone at the top, negative segregation near the bottom in the equiaxed zone, inverse segregation near the ingot surface, V-segregates along the centerline, and A-segregates in the columnar zone [2, 3]. It is well established that the macroscopic transport of species leading to macrosegregation can occur by a variety of mechanisms, including thermally and solutally driven natural convection of the melt in the mushy zone, flow due to solidification contraction, and the sedimentation of free equiaxed crystals. Fredriksson and coworkers [ 4,5] provide recent overviews of the solidification transport phenomena and macrosegregation in ingot casting."

Jan 1, 1999

By L. Yin, R. B. Haber, N. Sobh, D. A. Tortorelli, R. W. Hyland Jr.

"We optimize continuous quench process parameters to produce a desired precipitate distribution in aluminum alloy extrudates. To perform this task, an optimization problem is defined and solved using a standard nonlinear programming algorithm. Ingredients of this algorithm include a cost function, constraint functions and their sensitivities with respect to the process parameters. These functions are dependent on the temperature and precipitate size which are obtained by balancing energy to determine the temperature distribution and by using a reaction-rate theory to determine a discrete precipitate particle size distribution. Both the temperature and the precipitate models are solved via the finite element method. Since we use a discrete particle size model, there are as many as 105 degrees-of-freedom per finite element node. After we compute the temperature and precipitate size distributions, we must also compute their sensitivities. This seemingly intractable computational task is resolved by using an element-by-element discontinuous Galerkin finite element formulation and a direct differentiation sensitivity analysis which allows us to perform all of the computations on a PC.1 IntroductionThis work addresses the need for an integrated design capability that links microstructure evolution to the process parameters. It is motivated by the manufacture of lightweight aluminum-alloy extrusions for use in automotive structures. Aluminum alloys offer obvious benefits, however, care must be taken to manufacture favorable microstructures that ensure acceptable structural performance. For example, the manufacturing process for 6000-series components involves hot extrusion of cast aluminum billets followed by either an air or water quench process. The bill~t's initial grain structure is dramatically altered during extrusion by massive mechanical deformations and recrystallization processes. The microstructure continues to evolve during the quench, as complex chemical processes determine the formation of precipitates. The control of the precipit'ate size distribution is vital. Indeed, large precipitates located on grain boundaries serve as crack initiation sites which adversely effect structural crash· worthiness."

Jan 1, 2000

By Kazuyoshi Shimakage, Shinji Hirai, Kenji Wada

"An amorphous zirconium oxide coating was prepared by the sol-gel process using zirconium tetra-n-butoxide on the surface of aluminum to improve the corrosion resistance to salt, acid and alkaline attacks. The coating films formed on the smooth aluminum substrates under UV-irradiation indicated an excellent corrosion resistance for salt, acid and alkaline attack tests. For example, the corroded area of coating film in salt attack test for 3600ks in the order of sol-gel coating· film< chromate film <boehmite film, and the sol-gel coating film had the best corrosion resistance. The coating film prepared on the coarse aluminum substrate by a boiling treatment after heat treatment at 573K also had greater corrosion resistance, and a water-avid surface appeared a contact angle of approximately 3°.IntroductionAs given in a previous paper1; a composite film consisting of a porous layer of anodically grown aluminum oxide filled with amorphous zirconium oxide and an amorphous zirconium oxide coating layer deposited thereon via the sol-gel process utilizing the dip-coating technique, was prepared to improve the alkaline corrosion resistance of aluminum. The alkaline corrosion resistance of these composite films was increased in the range of 24 to 50 times those of conventional anodic oxide films anodized in sulfuric acid. As a result, it was proved that heat treatment at 573K after dip-coating was an important process to .remove organic component from gel film and to accelerate the densification of coating layer. Furthermore, the effect of ultraviolet (UV) irradiation at ambient temperature on the densification of coating layer was also examined to lower the heat-treatment temperature2.Then, a sol-gel film prepared by UV irradiation at ambient temperature indicated that alkaline corrosion resistance of aluminum was superior in the range of 2.4 times to 2. 6 times that of the conventional composite film heated at 573K."

Jan 1, 2000

By T. Ahokainen, J. Pitkälä, J. L. Xia, A. Jokilaakso, J. Vaamo

"The aim of the present paper is to use the two CFD codes to model the two phase flow in a water model ladle with central gas injection. The codes examined are CFX and Phoenics. An Eulerian two phase model is used and predictions are compared against the experimental data available. The results show that the codes can reasonably well predict the gas-liquid plume in the ladle, and predictions are generally in a good agreement with experimental data. However, differences do exist in predicting the gas volume fraction and velocity profiles. The results should be interpreted most carefully and cautiously, because they are very sensitive to the boundary conditions and dependent on the models for the physical phenomena involved. IntroductionSubmerged gas injection has widely been used in the metallurgical industry for more than a century. At the present, the use of gas is most effective in steelmaking industry where the advantages of the gas injection have already been long well understood. Effective mixing, large contact area between reactants, easy modifications and flexibility of the processes are the most important advantages. Disadvantages include refractory wear, blocking in the tuyeres, and splashing. These disadvantages can be reduced and advantages further improved by studying the flow phenomenon in process vessels. However, it is difficult to study flow in a real vessel because of the high temperatures and physical and mathematical modelling is therefore increasingly used in the process development work."

Jan 1, 1999

By S. P. Vanka, B. G. Thomas, S. Sivaramakrishnan

"During the continuous casting of steel, transient 'flow events can be very important to the generation of quality problems, such as shear entrainment, surface level fluctuations and bubble entrainment. These phenomena can be better predicted using Large Eddy Simulation (LES) models than the K-E models, which have been extensively studied. In this work the turbulent transient flow in a water model of a continuous caster has been both simulated using LES models and measured using Particle Image Velocimetry (PIV). The results of PIV and LES have been compared to validate the LES model and also to enhance the understanding of the prominent transient features of the flow field. The flow near the top surface in PIV was found to contain periods of 5-1 Os when the velocities were three to four times their mean values, which is of importance to the shear entrainment of the liquid flux. In both simulation and PIV the upper roll structure is found to change chaotically from a single large recirculation structure to a set of distinct vortices. The inlet swirl in PIV is seen to persist more than halfway across the mold, causing a characteristic staircase velocity vector pattern when viewed in a plane parallel to the wide faces. The lower rolls in PIV are significantly asymmetric for very long periods of time (- I-hour) and go through a repeating sequence of features. One of these features involving a short circuit between the upward and downward flow in the lower roll is also seen in the simulation and is of significance to bubble entrapment.IntroductionThe turbulent flow through the nozzle and in the mold of the continuous caster has been studied extensively using computational Reynolds Averaged Navier Stokes (RANS) models of turbulent flow [1,2]. Defects, such as internal inclusion of liquid fl4x through surface shear, pencil pipe defects due to bubble entrapment, surface defects due to level fluctuations are caused by transient flow phenomena oc'curring in the mold. These phenomena can be better predicted using transient Large Eddy Simulation [3] or ""LES"" models."

Jan 1, 2000