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  • 51.
    Liu, Yu
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing. Central Iron and Steel Research Institute, Beijing, P.R. China.
    Ersson, Mikael
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    Liu, Heping
    Cent Iron & Steel Res Inst, Beijing 100081, Peoples R China..
    Jönsson, Pär Göran
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    Gan, Yong
    Cent Iron & Steel Res Inst, Beijing 100081, Peoples R China..
    A Review of Physical and Numerical Approaches for the Study of Gas Stirring in Ladle Metallurgy2019In: Metallurgical and materials transactions. B, process metallurgy and materials processing science, ISSN 1073-5615, E-ISSN 1543-1916, Vol. 50, no 1, p. 555-577Article, review/survey (Refereed)
    Abstract [en]

    This article presents a review of the research into gas stirring in ladle metallurgy carried out over the past few decades. Herein, the physical modeling experiments are divided into four major areas: (1) mixing and homogenization in the ladle; (2) gas bubble formation, transformation, and interactions in the plume zone; (3) inclusion behavior at the steel-slag interface and in the molten steel; and (4) open eye formation. Several industrial trials have also been carried out to optimize gas stirring and open eye formation. Approaches for selecting criteria for scaling to guarantee flow similarity between industrial trials and physical modeling experiments are discussed. To describe the bubble behavior and two-phase plume structure, four main mathematical models have been used in different research fields: (1) the quasi-single-phase model, (2) the volume of fluid (VOF) model, (3) the Eulerian multiphase (E-E) model, and (4) the Eulerian-Lagrangian (E-L) model. In recent years, the E-E model has been used to predict gas stirring conditions in the ladle, and specific models in commercial packages, as well as research codes, have been developed gradually to describe the complex physical and chemical phenomena. Furthermore, the coupling of turbulence models with multiphase models is also discussed. For physical modeling, some general empirical rules have not been analyzed sufficiently. Based on a comparison with the available experimental results, it is found that the mathematical models focusing on the mass transfer phenomenon and inclusion behaviors at the steel-slag interface, vacuum degassing at the gas-liquid interface, dissolution rate of the solid alloy at the liquid-solid interface, and the combination of fluid dynamics and thermodynamics need to be improved further. To describe industrial conditions using mathematical methods and improve numerical modeling, the results of physical modeling experiments and industrial trials must offer satisfactory validations for the improvement of numerical modeling.

  • 52.
    Muhmond, Haji Muhammad
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    On the Inoculation and Graphite Morphologies of Cast Iron2014Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Research was conducted to understand the nucleation mechanism of graphite flakes and nodules and the effect of various elements on the growth morphology of graphite. Investigations were started on flake graphite cast iron. The effect of S on the graphite morphology and MnS was experimentally analysed. The influence of various type of oxides on the growth morphology of MnS and their relation with the graphite growth morphology was studied carefully through series of experiments, and results were related to the thermodynamic calculations, performed to predict the nucleation of oxides and sulfides at any temperature. The calculations were supported by EDX analysis on particles in the samples, showing sequential nucleation of flake graphite. The austenite volume fraction and the dendrite growth orientations were affected by the addition of Al to the melt. The effect of aluminium oxide and sulfur was studied on the austenite growth morphology with the help of colour etching technique. Thermal analyses were performed to study the effect of sulfur content on austenite volume fraction and growth morphology using DSC. The latent heat of solidification and the rate of austenite formation was studied and related to the sulfur content in the alloy.

    To study the effect of O and S on the graphite morphology, pure Fe-C alloy was prepared and strong de-oxidizers and de-sulfurizer (Mg, Ca and Sr) were tested. With the help of ion etching and polishing, we were able to reveal the graphite growth morphology. The morphological changes in the graphite were explained by relating it to the composition of the melt in regard of dissolved S and O in the melt. The effect of other trace elements such as S, F, O, N, P, B and Se, was also investigated by testing them on an ultra-pure Fe-C alloy. The possibility of substituting a foreign atom in the basal plane of graphite was analysed based on the bonding energy between C and the foreign atoms. The resulting change in the structure of the basal plane was studied using Avogadro software and the resulting model were compared with the experimental results. The basal plane of nodular, flake and undercooled graphite was studied with the help of HRTEM, which showed differences in the lattice spacing between different graphite morphologies. The latent heat measurement showed that flake graphite have higher energy than the undercooled or vermicular graphite. This research made us enabled to tell about the growth along c-plane in graphite and the reason behind the transition of graphite morphology.

    The effect of inoculation temperature and inoculation sequence on the nodularity was studied. EDX analysis were performed and the results were compared to the thermodynamic calculations.  It was found that, the melt composition is controlling the graphite growth morphologies. Strong de-oxidizers and de-sulfurizer are necessary to reduce O and S to a level where it does not influence the graphite growth morphology. The effect of various elements on the activity of oxygen in the melt is calculated. High Al cast iron was also studied. The major problem associated with this type of alloy was that, the Mg was not effective in producing nodular graphite. Experiments showed that de-oxidizers stronger than Mg are required to increase the nodularity. Thermodynamic calculations showed that the activity of oxygen in the melt was changing strongly by increasing the Al content in the alloy. This was increasing the required oxygen level to nucleate MgO.

  • 53.
    Nassar, Hani
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    On Peritectic Reactions and Transformations and Hot Forming of Cast Structures2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis deals with peritectic reactions and transformations that occur during the solidification of many alloys. Peritectics are believed to be a major cause of crack-formation in many steels, thus, good knowledge of the mechanisms by which these phenomena occur is essential for preventing such defects. The thesis also handles the behaviour of metals, in particular cast structures, during hot forming. Grain size and microstructure are of most importance in determining the strength, toughness and performance of a steel. For achieving enhanced mechanical and microstructural properties, good understanding of the phenomena occurring during hot forming is required.

    Peritectic reactions and transformations were studied in Fe-base and steel alloys through differential thermal analysis (DTA) experiments and micrographic investigation of quenched DTA samples. The effect of the ferrite/austenite interface strain during the peritectic reaction on equilibrium conditions was thermodynamically analysed, and the results were related to temperature observations from DTA experiments conducted on Fe-base alloys and low-alloy steels. Massive transformations from ferrite to austenite were observed in the micrographs of a number of quenched low-alloy steel samples and it was proposed that these transformations are uncontrolled by diffusion, and occur in the solid state as a visco-plastic stress relief process. DTA study of an austenitic stainless steel indicated that the alloy can exhibit primary precipitations to either ferrite or austenite. A continuously-cast breakout shell of the steel was analyzed and it was suggested that the observed irregularities in growth were due to alternating precipitations of ferrite and austenite; parts of the shell with higher ratios of primary-precipitated ferrite shrink in volume at the peritectic temperature and experience reduced growths.

    An experimental method for studying the behaviour of metals during hot forming developed, and hot compression tests were conducted on cast copper and ball-bearing steel samples. Flow stress curves were obtained at varying temperatures and strain rates, and the results showed good agreement with earlier observations reported in literature. Micrographic analysis of quenched samples revealed variations in grain size and a model was fitted to describe the grain size as a function of deformation temperature and strain.

    Solidification growth during continuous casting of stainless steel and copper was numerically modelled. A varying heat transfer coefficient was proposed to approximate the experimentally measured growth irregularities in the continuously-cast stainless steel breakout shell. Solidification growth of pure copper was also modelled in the Southwire continuous casting process. Temperature measurements from the chill mould were used to approximate the temperature gradient and the heat extraction from the solidifying strand, and the results were used in a two-dimensional model of solidification.

     

     

  • 54.
    Nassar, Hani
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    Fredriksson, Hasse
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    On the effect of strain on peritectic reactions and transformations in Fe-Ni and Fe-Cu binary alloys2009In: International Journal of Cast Metals Research, ISSN 1364-0461, E-ISSN 1743-1336, Vol. 22, no 1-4, p. 232-235Article in journal (Refereed)
    Abstract [en]

    Differential thermal analysis (DTA) experiments conducted on Fe-Ni and Fe-Cu alloys showed undercooling below the equilibrium peritectic temperatures, T-P. The intervals between the observed liquidus and peritectic temperatures were on average 11 degrees C and 8 degrees C larger than the intervals obtained from equilibrium phase diagrams of Fe-Ni and Fe-Cu respectively. The transformation from delta-Fe to gamma-Fe during the peritectic reaction is associated with density change and strain build up at the delta-Fe/gamma-Fe interface. Thermodynamic calculations showed that by introducing the strain energy at the delta-Fe/gamma-Fe interface, T-P dropped 9 K below its equilibrium value and the increase in the liquidus-to-peritectic temperature interval was in reasonable agreement with the experimental observations. The growth rate of gamma-Fe during a peritectic transformation was calculated based on the strain-induced undercooling in T-P and the results showed partial agreement with observations obtained from CSLM directional solidification experiments conducted earlier on Fe-Ni alloys.

  • 55.
    Nassar, Hani
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    Korojy, Bahman
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Fredriksson, Hasse
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    A study of shell growth irregularities in continuously cast 310S stainless steel2009In: Ironmaking & steelmaking, ISSN 0301-9233, E-ISSN 1743-2812, Vol. 36, no 7, p. 521-528Article in journal (Refereed)
    Abstract [en]

    Growth irregularities in continuous casting are believed to be associated with crack formation and breakouts. Differential thermal analysis on 310S stainless steel samples indicated primary precipitations of both austenite and ferrite during solidification. In tensile tests on solidifying samples, abrupt shrinkages in volume were detected in the peritectic range of temperatures. Micrographic and microsegregation analysis on samples extracted from a breakout shell revealed high ratios of primary-precipitated austenite in the thick sections of the shell, and high ratios of primary-precipitated ferrite in the thin sections. Alternating precipitations of austenite and ferrite are proposed to occur during solidification. Regions of the shell with high ratios of primary austenite remain in contact with the mould and exhibit high growth rates, whereas regions with high ratios of primary ferrite shrink in volume due to the ferrite to austenite transformation, which results in the formation of air gaps between the shell and the mould and reductions in growth rate.

  • 56. Peet, Mathew James
    et al.
    Hulme-Smith, Christopher
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing. University Of Cambridge.
    Stone, H. J.
    Partitioning and supersaturation of carbon in low-temperature bainite2015In: PTM 2015 - Proceedings of the International Conference on Solid-Solid Phase Transformations in Inorganic Materials 2015, 2015Conference paper (Refereed)
  • 57.
    Ranganathan, Sathees
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    Makaya, Advenit
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    Fredriksson, Hasse
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    Influence of Mo in the structure of rapidly solidified Fe-Mo-Cr-Mn-Si-C alloy2009In: International Journal of Cast Metals Research, ISSN 1364-0461, E-ISSN 1743-1336, Vol. 22, no 1-4, p. 264-267Article in journal (Refereed)
    Abstract [en]

    An Fe-Mo-Cr-Mn-Si-C alloy was prepared in an induction furnace and was cast into cylindrical rod in a copper mould in castmatic equipment (low pressure casting). A single phase non-equilibrium featureless (no visible microstructures after deep etching) phase was observed over a certain range of thickness of the rod. In this present work, the extent of the featureless phase was studied with different concentrations of Mo (5-25 wt-%) for 5.5 mm diameter of cylindrical rod at a cooling rate of 1100 K s(-1). Light optical microscopy, scanning electron Microscopy and Vickers hardness tests were used to analyse the samples. The amount of the featureless area varies as the Mo content changes and the maximum featureless area was obtained for 7 wt-% of Mo. This single phase featureless structure exhibits very high hardness (>1350 HV) which can be used in many interesting applications with or without suitable heat treatments.

  • 58.
    Ratnasari, Devy Kartika
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Yang, Weihong
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology. KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Jönsson, Pär
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    Two-stage ex-situ catalytic pyrolysis of lignocellulose for the production of gasoline-range chemicals2018In: Journal of Analytical and Applied Pyrolysis, ISSN 0165-2370, E-ISSN 1873-250X, Vol. 134, p. 454-464Article in journal (Refereed)
    Abstract [en]

    The appropriate system is needed to produce a scalable and economically viable renewable energy from biomass. The objective of this study is to improve the quality of bio-oil, in terms of Organic Liquid Product (OLP), water content, acidity, favourable fractions, as well as gasoline-range chemicals. The influence of a staged layered catalyst system consists of a mesoporous catalyst, Al-MCM-41, and a microporous catalyst, HZSM-5, on the bio-oil quality was investigated. Additionally, the effect of reaction temperatures in the range of 400-600 degrees C with the optimum staged catalyst system on the catalytic pyrolysis product was analysed. The experiments of lignocellulosic biomass pyrolysis and catalytic pyrolysis were performed using a fixed bed reactor equipped with oil condensers and a gas collection sample bag. The quality of bio-oil produced from the thermal pyrolysis of lignocellulosic biomass, catalytic pyrolysis with single catalysts, catalytic pyrolysis with the staged catalyst system, as well as catalytic pyrolysis with mixed catalyst system was studied. The results show that Al-MCM-41 with HZSM-5 in the staged catalyst system enhanced the production of favourable compounds: hydrocarbons, phenols, furans, and alcohols. The favourable compounds yield that boosted 5.25-6.43% of that with single HZSM-5 catalyst was produced with HZSM-5:Al-MCM-41 mass ratio of 3:1 and 7:1. The pyrolysis and catalysis temperature of 500 degrees C with HZSM-5:Al-MCM-41 ratio of 3:1 obtained the optimum quality of bio-oil with 11.08 wt.% of OLP, 76.20% of favourable fractions, 41.97 wt.% of water content, low TAN of 43.01 mg-KOH/g, high deoxygenation, as well as high gasoline-range production of 97.89%.

  • 59.
    Sanet, Jan
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Nassar, Hani
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Fredriksson, Hasse
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    Hot Working Behaviour of Cast Metal Samples2009Report (Other academic)
  • 60.
    Schmidt, Christoffer
    et al.
    KTH.
    Andersson, Nils A. I.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Tilliander, Anders
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Process Metallurgy.
    Jönsson, Pär
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    Ljungqvist, P.
    Measurement techniques for meltdown control in a stainless steel AC electric arc furnace2017In: ESSC and DUPLEX 2017 - 9th European Stainless Steel Conference - Science and Market and 5th European Duplex Stainless Steel Conference and Exhibition, Associazione Italiana di Metallurgia , 2017Conference paper (Refereed)
    Abstract [en]

    A method for vibrational evaluations of spectrogram data from pilot plant measurements was established for obtaining a consistent analysis of the molten scrap state. Not knowing the meltdown progress inside the furnace results in an inefficient power scheduling, which affects refractory life, process time and energy losses. Hence, there exists potential to control the furnace power so that it is kept high while there is sufficient amounts of scrap inside furnace to absorb the input energy. Thus, harmonic distortions of the electric current and measurements of the sound and vibrations emitted from the furnace were correlated to the molten state of the scrap. By using this method, a reduction in melting time in the order of minutes per heat can be obtained. The method was found to give stable signals and it was judged to be a good candidate for implementation in industry. Furthermore, the developed method is universal and may be applied for other types of signals and combined into intelligent soft sensor systems. 

  • 61. Tinoco, J.
    et al.
    Widell, Björn
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Fredriksson, Hasse
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    Metal spray deposition of cylindrical preforms2005In: Materials Science & Engineering: A, ISSN 0921-5093, E-ISSN 1873-4936, Vol. 413, p. 56-65Article in journal (Refereed)
    Abstract [en]

    A number of deposition experiments were carried out in a metal spray deposition facility for cylindrical preforms, at Sandvik Steel AB. Thick layers of modified Inconel 625 were sprayed over steel bars 170 mm in diameter and 8 m long. The rods were at room temperature during the deposition process. The effect of rotational velocity and fraction solidified in the spray was studied. Measurements of grain length intercept and porosity content were performed, as well as estimations of the shape of the actual deposition profile. Microprobe analysis was accomplished in different locations on the samples. A computational fluid dynamic model is implemented together with a continuum heat transfer model in order to facilitate the analysis. The range of the rotational velocity studied did not show any large effect on the formation of the base porosity. Three main zones were identified in the microstructure, i.e. porous-dendritic, transition and equiaxed. The segregation patterns suggested that a chemical homogenization occurred during the process. This was supported by the results of the numerical calculations.

  • 62.
    Yan, Baijun
    et al.
    Univ Sci & Technol Beijing, Sch Met & Ecol Engn, Dept Phys Chem Met, Beijing 100083, Peoples R China..
    Liu, Yixiang
    Univ Sci & Technol Beijing, Sch Met & Ecol Engn, Dept Phys Chem Met, Beijing 100083, Peoples R China..
    Shu, Qifeng
    Univ Sci & Technol Beijing, Sch Met & Ecol Engn, Dept Phys Chem Met, Beijing 100083, Peoples R China..
    Deng, Tengfei
    Wuhan Univ Technol, State Key Lab Silicate Mat Architectures, Wuhan 430070, Hubei, Peoples R China..
    Glaser, Björn
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    Measurements and Model Estimations of Viscosities of the MnO-CaO-SiO2-MgO-Al2O3 Melts2019In: Metallurgical and materials transactions. B, process metallurgy and materials processing science, ISSN 1073-5615, E-ISSN 1543-1916, Vol. 50, no 1, p. 376-384Article in journal (Refereed)
    Abstract [en]

    The viscosities of the MnO (0 to 55 mass pct)-CaO-SiO2-MgO (5 mass pct)-Al2O3 (20 mass pct) melts were measured by rotating cylinder method in the temperature range from 1573 K to 1873 K (1300 degrees C to 1600 degrees C). The measurements were carried out in the atmosphere of flowing CO/CO2 gas mixture with a volume ratio of 99/1, and molybdenum crucible and spindle were adopted. The results reveal that MnO is a viscosity reducing component, and the effect of MnO is more notable in the melts with higher ratio of CaO to SiO2. For example, in the melts with the mass ratio of CaO to SiO2 equal to 0.6, the addition of 5 mass pct MnO only slightly reduced the viscosities. Comparatively, the addition of 5 mass pct MnO made the viscosities of the melts with the mass ratio of CaO to SiO2 equal to 1.0 and 1.5 decrease remarkably. Based on the measured data, the viscosities estimation model proposed in our previous study was extended to the system containing MnO, and the model parameters were determined. The model can estimate and predict the viscosities of the aluminosilicate melts containing MnO well, and then some iso-viscosity contours of this system were calculated. From the iso-viscosity contours, it can be seen that MnO is almost equivalent to CaO in reducing the viscosities in the melt with high SiO2 content, while with the decrease of the SiO2 content MnO becomes more effective than CaO.

  • 63. Zhang, H.
    et al.
    Nakajima, Keiji
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Su, M.
    Shibata, H.
    Hedström, Peter
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Wang, W.
    Lei, H.
    Wang, Q.
    Jönsson, Pär
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    He, J.
    Prediction of Influences of Co, Ni, and W Elements on Carbide Precipitation Behavior in Fe–C–V–Cr–Mo Based High Speed Steels2018In: Steel Research International, ISSN 1611-3683, E-ISSN 1869-344X, Vol. 89, no 10, article id 1800172Article in journal (Refereed)
    Abstract [en]

    The effects of Co, Ni together with W addition on the precipitation sequence, amount, and composition of carbides and FCC matrix in Fe–C–V–Cr–Mo based alloys are investigated with the help of Partial Equilibrium (PE) approximation and thermodynamic calculations as well as differential scanning calorimetry (DSC) and electron backscatter diffraction (EBSD) - energy dispersive spectrometer (EDS) analyses. Results show that, individually, Co and Ni elements strengthen the matrix by their great solubility in FCC matrix; W element enlarges the hardness of the alloy through benefiting the formation of M6C carbide. Mutually, the addition of Co and Ni together with W increases the precipitation temperature of the eutectic carbides, although the addition of Co and Ni itself exerts little influence on the nature (type, amount, and composition) of the carbides. These predictions combined with the experimental verifications provide potentials for the alloy design and the property control in high speed steels.

  • 64.
    Zhao, Zengwu
    et al.
    Inner Mongolia Univ Sci & Technol, Inner Mongolia Key Lab Utilizat Bayan Obo Multime, Elected State Key Lab, Baotou 014010, Peoples R China..
    Chen, Xuexin
    Univ Sci & Technol Beijing, Dept Phys Chem Met, Beijing 100083, Peoples R China..
    Glaser, Björn
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    Yan, Baijun
    Univ Sci & Technol Beijing, Dept Phys Chem Met, Beijing 100083, Peoples R China..
    Experimental Study on the Thermodynamics of the CaO-SiO2-Ce2O3 System at 1873 K2019In: Metallurgical and materials transactions. B, process metallurgy and materials processing science, ISSN 1073-5615, E-ISSN 1543-1916, Vol. 50, no 1, p. 395-406Article in journal (Refereed)
    Abstract [en]

    The phase relations in the CaO-SiO2-Ce2O3 system under the reducing atmosphere at 1873 K were determined by the conventional equilibrium and quenching method combined with scanning electron microscopy-electron probe microanalysis (SEM-EPMA) and X-ray diffraction (XRD) measurements on the quenched samples. Based on these analyses, a large part of the isothermal phase diagram was constructed. Furthermore, the thermodynamic activities of Ce2O3 in the melts at 1873 K were measured by the chemical equilibrium method. Using the measured activity data, an empirical formula to estimate the activity coefficient of Ce2O3 was proposed based on the regular solution model. It was found that, for the melts with the same Ce2O3 contents, the thermodynamic activities of Ce2O3 increase gradually with the rise of basicity (the ratio of CaO to SiO2) of the melts. This implies that, from the thermodynamic point of view, the increase of basicity is favorable to the enrichment and precipitation of Ce-containing mineral phases.

  • 65. Åberg, J.
    et al.
    Vynnycky, M.
    Fredriksson, Hasse
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    Heat-flux measurements of industrial on-site continuous copper casting and their use as boundary conditions for numerical simulations2009In: Transactions of the Indian Institute of Metals, ISSN 0019-493X, Vol. 62, no 4-5, p. 443-446Article in journal (Refereed)
    Abstract [en]

    An embedded sensor, designed for rapid and accurate response times and using wireless data transmission, has been developed for the on-site measurement of temperatures in industrial continuous casting moulds. The sensor has been used to measure the temperature at several points in the mould during production in a Southwire copper casting process. The measured data has been used to calculate the temperature gradient in the mould to estimate the heat flux through it; this is then used as a boundary condition for numerical simulations of solidification. For these, we employ a method that tracks the solidification front explicitly; this has an advantage over fixed-grid methods in simulations for materials having a short solidification interval, since the release of latent heat at the solidification front can be resolved without resorting to a very fine mesh. The special considerations required for setting the initial condition for the numerical scheme and the time taken for the superheated melt to form a solid shell are also discussed.

  • 66.
    Åberg, Jonas
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    Fredriksson, Hasse
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    An On-site Industrial Experimental Heat Flux Study during Solidification of Pure Copper in the Southwire Process2007In: T INDIAN I METALS, ISSN 0972-2815, Vol. 60, no 2-3, p. 191-196Article in journal (Refereed)
    Abstract [en]

    To study the production of pure copper and copper alloys in the Southwire process the temperature in the mould has been measured on-site in the production process in a number of positions. To increase the accuracy and robustness of measurements a new type of thermocouple based temperature sensor has been developed and tested. The test system includes wireless transmission of measured data from the moving mould. The results from the measurements are then used to calculate the energy transfer rate from the solidifying shell as a function of time. An initial in-situ measurement campaign has been performed and the results are very promising.

  • 67.
    Åberg, Jonas
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    Vynnycky, Michael
    KTH, School of Engineering Sciences (SCI), Centres, Faxén Laboratory.
    Widell, Björn
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    Development of a finite element model for study of the developing stress and strain in a solidifying shell2006Report (Other academic)
  • 68.
    Åberg, Jonas
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    Widell, Björn
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    Fredriksson, Hasse
    Intrinsic Material Damping in Mg, Al and Fe Alloys and a Discussion of its Dependence on the Internal Structure of the Material2006Report (Other academic)
  • 69.
    Åberg, Jonas
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    Widell, Björn
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Processing.
    Larsson, Petra
    Investigation of the Damping in Twelve Metallic Plates Using Frequency Response2006Report (Other academic)
12 51 - 69 of 69
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