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  • 101.
    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)
  • 102.
    Sarnet, Jan
    et al.
    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.
    Ultrasonic Evaluation of Imperfections and Defects in Cast Steel Ingot Samples Using Immersion Tank Testing2009Report (Other academic)
  • 103.
    Sarnet, 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.
    Hot Deformation Testing of Cast Metal Samples2009Report (Other academic)
  • 104.
    Tadesse, Abel
    et al.
    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.
    Experimental studies of gray cast iron solidification with Linear Variable Differential Transformer2015In: Advances in the Science and Engineering of Casting Solidification: An MPMD Symposium Honoring Doru Michael Stefanescu, The Minerals, Metals, and Materials Society, 2015, p. 305-312Conference paper (Refereed)
    Abstract [en]

    Expansion during the solidification of gray cast iron was studied by the help of Linear Variable Differential Transformer (LVDT). The chemical composition of the samples was altered by adding two types of inoculant; Superseed® (50% Si, 1% Sr and 0.5% Al) and SMZ® (69% Si, 1.9% Ca, 0.7% Ba, 5% Zr, 4.5% Mn and 1.3% Al). During the solidification, the melt shows hardly no shrinkage in the primary austenite formation region, but the eutectic region shows higher expansion. The expansion during the eutectic growth increase, when the inoculant weight percentage escalates. At the same time, the eutectic cells get smaller and increases in cells number. The micrograph reveals undercooled and interdendritic graphite transformed to homogenized flake graphite. The inoculation process reduces the solidification rate along with different stable oxide and sulfide nuclei's created prior to the solidification, as a result eutectic cell gets more sites to grow. The change in micrograph and solidification rate was believed to modify the mechanical property of the cast.

  • 105.
    Tadesse, Abel
    et al.
    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, Casting of Metals.
    On the Solidification and Structure Formation during Casting of Large Inserts in Ferritic Nodular Cast Iron2018In: Metallurgical and materials transactions. B, process metallurgy and materials processing science, ISSN 1073-5615, E-ISSN 1543-1916, Vol. 49, no 3, p. 1223-1235Article in journal (Refereed)
    Abstract [en]

    The graphite nodule count and size distributions for boiling water reactor (BWR) and pressurized water reactor (PWR) inserts were investigated by taking samples at heights of 2160 and 1150 mm, respectively. In each cross section, two locations were taken into consideration for both the microstructural and solidification modeling. The numerical solidification modeling was performed in a two-dimensional model by considering the nucleation and growth in eutectic ductile cast iron. The microstructural results reveal that the nodule size and count distribution along the cross sections are different in each location for both inserts. Finer graphite nodules appear in the thinner sections and close to the mold walls. The coarser nodules are distributed mostly in the last solidified location. The simulation result indicates that the finer nodules are related to a higher cooling rate and a lower degree of microsegregation, whereas the coarser nodules are related to a lower cooling rate and a higher degree of microsegregation. The solidification time interval and the last solidifying locations in the BWR and PWR are also different.

  • 106.
    Tadesse, Abel
    et al.
    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.
    The effect of inoculation on the thermal expansion/contraction during solidification of gray cast iron2014In: 6th International Conference on Solidification and Gravity, 2014, p. 447-451Conference paper (Refereed)
    Abstract [en]

    Inoculation of casting used to improve the microstructure and the properties of the component. Depending upon the area of application, gray cast iron has different microstructure and mechanical properties. The type and amount of the inoculation result in shape and orientation differences of the flake graphite. The Linear Variable Differential Transformer (LVDT) shows a variation in displacements change during the solidification. Temperature measurement used to analyze cooling curves and microstructural analysis of sample to examine the physical differences. The microstructural study used for describing the variation in area fraction and shape of graphite. The experimental result indicates contraction in austenite formation region, and expansion in eutectic formation region. The effect of the inoculant and the superheat temperature shows a variation in degree of expansion/contraction and cooling rates of the experiments. Effective inoculation results in homogenizing the eutectic structure, reducing the undercooled and interdendritic graphite throughout the structure. Inoculation of the alloy results in higher expansion in eutectic formation region. Differences in eutectic formation region were observed due to variation in equilibrium point, and it needs carful investigation in future works.

  • 107.
    Tadesse, Abel
    et al.
    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.
    The effects of carbon on the solidification of nodular cast iron- its study with the help of linear variable differential transformer and microstructural analysis2018In: International Journal of Cast Metals Research, ISSN 1364-0461, E-ISSN 1743-1336, Vol. 31, no 2, p. 108-117Article in journal (Refereed)
    Abstract [en]

    The effect of carbon on the solidification of ductile cast iron (DCI) was studied using linear variable differential transducers (LVDT) and microstructural analysis. Thermal expansion during the eutectic solidification was investigated by using LVDT and temperature measurements. The eutectic volume change was compared with the theoretical calculation. Furthermore, the primary austenite during solidification was evaluated by using differential thermal analysis and the samples undergo a dilatometer experimentation to assess the effect of cooling rates. It was found that the samples show no expansion in the transversal direction due to higher micro-shrinkages in the centre whereas in the longitudinal direction the samples shows expansion until solidification completed. The theoretical and measured volume changes agree with each other. The austenite fraction and micro-shrinkage pores decrease with increase in carbon content. The nodule count and distribution changes with carbon content. The thermal contraction of DCI is not influenced by carbon content variation at lower cooling rate.

  • 108.
    Tadesse, Abel
    et al.
    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.
    The experimental study of nodular cast iron volume changes during solidification2018In: 11th International Symposium on the Science and Processing of Cast Iron, SPCI-XI 2017, Trans Tech Publications Inc., 2018, Vol. 925, p. 140-146Conference paper (Refereed)
    Abstract [en]

    The volume changes during solidification of Nodular Cast Iron (NCI) in the sand mold studied using Linear Variable Differential Transformer (LVDT). Both hypo- and hyper-eutectic compositions are considered by adjusting the carbon fraction in the composition during the experimental studies. The microstructural analysis and measurements are taken from the samples to evaluate the different phases present, the nodule count and size distributions. At the beginning of solidification, the experimental result shows the volume change is negligible. During the eutectic growth, the samples expand until the end of solidification. The displacement measurement shows the expansion continued when solidification finished. The volume change studies during solidification indicate that as the carbon fraction increases the volume expansion decreases. On the other hand, it is found that the pore fraction decreases as the volume expansion decreases. The fraction of primary austenite decreases as the fraction of carbon increases, and that leads to having a lower pore fraction.

  • 109.
    Tadesse, Abel
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Casting of Metals.
    Fredriksson, Hasse
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Casting of Metals.
    Volume change during the solidification of grey cast iron: its relation with the microstructural variation, comparison between experimental and theoretical analysis2017In: International Journal of Cast Metals Research, ISSN 1364-0461, E-ISSN 1743-1336, p. 1-12Article in journal (Refereed)
    Abstract [en]

    The expansion/contraction during the solidification of grey cast iron was studied using Linear Variable Differential Transformer (LVDT). The experiments were conducted with and without melt treatment. Two types of inoculant used for melt treatment: ASSC (Si, Ca, Sr & Al) and MBZCAS (Si, Ca, Zr, Ba, Mn & Al). Microstructural investigations carried out to quantify the eutectic cells, undercooled graphite, primary austenite and secondary dendritic arm spacing (SDAS). It was found that the casting shows hardly any shrinkage during early solidification but in the eutectic region, the casting expands until the end of solidification. The measured and the calculated volume changes are close to one another, but the former shows more expansion. The addition of MBZCAS promotes more flake graphite, and ASSC does not increase eutectic cells much. In addition to that, it lowers the primary austenite fraction, promotes more eutectic growth, decreases undercooled graphite and SDAS. As a result, the volume expansion changes in the eutectic region.

  • 110. Tinoco, J.
    et al.
    Delvasto, P.
    Quintero, O.
    Fredriksson, Hasse
    KTH, Superseded Departments, Materials Science and Engineering.
    Thermal analysis of nodular and lamellar eutectic cast iron under different cooling rates2003In: International Journal of Cast Metals Research, ISSN 1364-0461, E-ISSN 1743-1336, Vol. 16, no 03-jan, p. 53-58Article in journal (Refereed)
    Abstract [en]

    Thermal analysis was performed on neareutectic nodular and lamellar cast iron,alloys under different cooling rates. In a DTA setup, cooling rates from 0.08 K/sec to 0.35 K/sec were used, while in a mirror furnace setup cooling rates up to 55 K/sec were reached. At low cooling rates, the solidification behaviour was analyzed by interrupting the process through quenching. The volume fraction of each phase and substructure was evaluated together with the latent heat at different solidification times. It was observed that the growth rate of the nodules decreases with time. Measurements on the number of nodules indicate that the nucleation rate is constant through the solidification process. The measured latent heat of fusion varies along the solidification process for nodular cast iron but not for lamellar cast iron. This difference in the solidification behaviour may be explained by different diffusion kinetic laws. It was also found that the measured latent heat of fusion decreases when the cooling rate increases. Alloys with nodular graphite showed lower latent heat in comparison with the alloys with lamellar graphite at high cooling rates. This effect is explained by means of thermodynamics of lattice defects, such as vacancies, formed in the austenite and graphite phase during solidification.

  • 111. Tinoco, J.
    et al.
    Fredriksson, Hasse
    KTH, Superseded Departments, Materials Science and Engineering.
    Solidification of a modified Inconel 625 alloy under different cooling rates2004In: High Temperature Materials and Processes, ISSN 0334-6455, E-ISSN 2191-0324, Vol. 23, no 1, p. 13-24Article in journal (Refereed)
    Abstract [en]

    The solidification characteristics of a modified version of Inconel 625 alloy were studied under nonequilibrium conditions. To achieve this, samples were melted and then solidified under cooling rates ranging from 0.1 K/s to 8000 K/s using a modified DTA, a mirror furnace and levitation casting. Features such as solidification interval and latent heat of fusion were obtained from the cooling curves. The segregation patterns of a number of alloy elements were analysed as well as the amount of the different phases found in the microstructure. Three reactions were observed in the DTA thermographs, i.e. precipitation of austenite, niobium carbides and Laves. eutectic. The measured latent heat of fusion is not constant along the solidification process. Lower values of latent heat of fusion were measured as high cooling rates. The segregation behavior of the different solute elements indicates that the cooling rate promotes higher concentrations in solid solution. The amount of secondary phases decreases with increasing cooling rate. A theoretical explanation is given in terms of lattice defects formed in the solid and their interaction with the solute atoms.

  • 112. 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.

  • 113.
    Tinoco, José
    et al.
    KTH, Superseded Departments, Casting of Metals.
    Widell, Björn
    KTH, Superseded Departments, Casting of Metals.
    Fredriksson, Hasse
    KTH, Superseded Departments, Casting of Metals.
    Fuchs, Laszlo
    Modeling the in-flight events during metal spray forming2004In: Materials Science & Engineering: A, ISSN 0921-5093, E-ISSN 1873-4936, Vol. 365, no 1-2, p. 302-310Article in journal (Refereed)
    Abstract [en]

    In this work, the in-flight events occurring during deposition over a rotating substrate were modeled. The calculations were performed by solving the momentum and enthalpy equations for the gas. A Lagrangian approach was used to obtain the trajectories and thermal history of the droplets. A modified heat capacity model was used to simulate the release of latent heat due to the solidification of the droplets. Turbulent particle dispersion was not considered. The results showed that the droplet temperature strongly depends on the droplet diameter and on its location in the spray since the relative velocity between the gas and the droplets varies largely depending on the location. An estimation of the state of the spray is presented in terms of mass and thermal averages. The results showed that the average fraction of solid obtained in the spray depends on the initial conditions, such as gas temperature and particle size distribution parameters.

  • 114. Vinet, Bernard
    et al.
    Berne, Cecile
    Pasturel, A
    Desré, Pierre Jean
    Fecht, H.J.
    Fredriksson, Hasse
    KTH, Superseded Departments, Production Engineering.
    Gránásy, Laszlo
    Greer, A.L.
    Hermann, R.
    Löser, W.
    Magnusson, Lena
    KTH, Superseded Departments, Production Engineering.
    Study and Modelling of Nucleation and Phase Selection Phenomena: Application to Refractory Metals and Alloys from Drop-Tube Processing2001In: Microgravity Research and Aplications in Physical Sciences and Biotechnology: Proceedings of the First International Symposium held 10-15 September, 2000 in Sorrento, Italy. Edited by O. Minster and B. Schürmann. European Space Agency, ESA SP-454., 2001, Vol. SP454, p. 1123-Conference paper (Refereed)
  • 115. Vinet, Bernard
    et al.
    Magnusson, Lena
    KTH, Superseded Departments, Casting of Metals.
    Fredriksson, Hasse
    KTH, Superseded Departments, Casting of Metals.
    Desré, Pierrre Jean
    Correlations between surface and interface energies with respect to crystal nucleation2002In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 255, no 2, p. 363-374Article in journal (Refereed)
    Abstract [en]

    The energetic chemical and structural properties of interfaces between solid and liquid metals are of great interest in numerous applications. However, solid-liquid interfacial energies of metals are often determined by nucleation experiments, requiring particular attention to the measurements so obtained. The purpose of this paper is to conduct an analysis of the level of liquid undercooling of 3d-, 4d-, and 5d-transition metals, as well as of other common undercooled elements, through a critical survey of thermophysical data and experimental results. As already pointed out for the liquid-vapor surface energy sigma(LV), the solid-liquid interface energy sigma(LS) determined from the maximum amount of liquid undercooling is well connected to the position of the element in the periodic table, leading to the individualization of each behavior, including the size of the critical nucleus. The beta ratio of sigma(LS)/sigma(LV) is demonstrated to be an interesting dimensionless number by which to classify the elements into distinctive groups. No significant unexplained anomaly is identified, except for Co, supporting the belief that Turnbull's classical theory furnishes a robust support to describe the crystal nucleation in pure elements.

  • 116. Vinet, Bernhard
    et al.
    Magnusson, Lena
    KTH, Superseded Departments, Materials Processing.
    Fredriksson, Hasse
    KTH, Superseded Departments, Materials Processing.
    Desré, Pierre J.
    Correlation between surface and interface energies in transition metals with respect to crystal nucleation; other common undercooled elementsIn: Journal of Non-Equilibrium Thermodynamics, ISSN 0340-0204, E-ISSN 1437-4358Article in journal (Refereed)
  • 117.
    Vynnycky, Michael
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Saleem, Saud
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Casting of Metals.
    Fredriksson, Hasse
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Casting of Metals.
    An asymptotic approach to solidification shrinkage-induced macrosegregation in the continuous casting of binary alloys2018In: Applied Mathematical Modelling, ISSN 0307-904X, E-ISSN 1872-8480, Vol. 54, p. 605-626Article in journal (Refereed)
    Abstract [en]

    The modelling of macrosegregation in the continuous casting of alloys normally requires resource-intensive computational fluid dynamics (CFD). By contrast, here we develop an asymptotic framework for the case when macrosegregation is driven by solidification shrinkage; as a first step, a binary alloy is considered. Systematic asymptotic analysis of the steady-state two-dimensional mass, momentum, heat and solute conservation equations in terms of the shrinkage parameter indicates that the overall problem can be reduced to a hierarchy of decoupled problems: a leading-order problem that is non-linear, and a sequence of linear problems, with the actual macrosegregation of the solute then being determined by means of one-dimensional quadrature. A numerical method that solves this sequence is then developed and implemented, and yields realistic macrosegregation profiles at low computational cost.

  • 118.
    Vynnycky, Michael
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Casting of Metals.
    Saleem, Saud
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Casting of Metals.
    Fredriksson, Hasse
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Casting of Metals.
    Towards an asymptotic framework for solidification shrinkage-induced macrosegregation in the continuous casting of binary alloysManuscript (preprint) (Other academic)
    Abstract [en]

    The modelling of macrosegregation in the continuous casting of alloysnormally requires resource-intensive computational fluid dynamics(CFD). By contrast, here we develop an asymptotic framework for thecase when macrosegregation is driven by solidification shrinkage; as a firststep, a binary alloy is considered. Systematic asymptotic analysis of thesteady-state two-dimensional mass, momentum, heat and solute conservationequations in terms of the shrinkage parameter indicates that theoverall problem can be reduced to a hierarchy of decoupled problems: aleading-order problem that is non-linear, and a sequence of linear problems,with the actual macrosegregation of the solute then being determinedby means of one-dimensional quadrature.

  • 119. Yang, Wenchao
    et al.
    Fredriksson, Hasse
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Casting of Metals.
    Ji, Shouxun
    Halo formation of Zn-Al alloys under conventional solidification and intensive convection solidification2017In: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 696, p. 460-469Article in journal (Refereed)
    Abstract [en]

    A halo occurred usually as an envelope of one phase around a primary phase in many alloys after solidification. Its formation mechanism was investigated for hypoeutectic, eutectic and hypereutectic compositions of Zn-Al alloys under conventional solidification and under intensive convection solidification. It was found that the Zn-rich halos occurred in the surroundings of the Al-rich primary phase for the hypereutectic Zn-Al alloys at Al> 5 wt% and no halos occurred for the hypoeutectic and eutectic Zn-Al alloys at Al <= 5 wt% under conventional solidification. However, the Zn-rich halos were completely absent from the Al-rich phase because of the uniform temperature distribution and enhanced mass transport under intensive convection solidification. Once the intensive convection was interrupted during solidification for the solid-liquid co-existing melt, a halo was formed on the surface of the existing Al-rich phase created either during the primary solidification or the eutectic solidification. Therefore, it was concluded that the halo formation should be a growth-dominant phenomenon not a nucleationdominant phenomenon. And, the interaction among the solid phases and the liquid phase was responsible for the halo formation, in which the difference in the elasticity modulus and the density of the different phases resulted in the variation of strain energy in the individual phase.

  • 120. 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.

  • 121.
    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.

  • 122.
    Åberg, Jonas
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Vynnycky, Michael
    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.
    Modelling of Thermal Stresses in Industrial Continuous Casting Processes2005In: Proceedings of the Femlab Conference, Stockholm, 2005Conference paper (Refereed)
    Abstract [en]

    This paper reports on progress in the implementationof COMSOL Multiphysics 3.2 to model thermalstresses in a three-dimensional solidifying shell, asoccurs typically in the industrial continuous casting ofcopper, copper alloys and steel. Computer memory requirementsprohibit a direct 3D numerical simulation ofthe temperature and the stresses. Instead, we use the factthat casting geometries are usually slender to divide thecalculation into three steps that are each less memoryintensive:(i) heat transfer and solidification is simulatedusing an arbitrary Lagrangian-Eulerian model; (ii) thetemperature solution is used to solve the force equilibriumequations in generalised plane strain mode appropriatefor a moving body; (iii) this solution is used tocompute the accumulated stress and strain in the body.Comparison between an analytical solution and a numericalsolution, that requires the simultaneous use ofseveral of Comsol Multiphysics’ peripheral features, ispresented.

  • 123.
    Åberg, Jonas
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Vynnycky, Michael
    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.
    Nassar, Hani
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Bergström, Thomas
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    An on-site experimental heat flux study and its interpretation in a FEMLAB finite element simulation of continuous casting of copper in the South-Wire process2005In: Transactions of the Indian Institute of Metals, ISSN 0019-493X, Vol. 58, no 4, p. 509-515Article in journal (Refereed)
    Abstract [en]

    The South-Wire process, a development of the Properzi process, to continuously cast copper has been studied both experimentally and by finite element computer simulation. The experimental work has been performed on site to get temperature data as a function of time at several locations within the mould. These experimental data have been used to evaluate boundary conditions for the heat transfer from the strand-mould interface and through the mould. A simulation model of the casting process has been developed in the program FEMLAB. In this program temperature varying material data and time varying boundary conditions have been used. The simulation model has been verified by comparing with an analytical solution, and then applied to the real physical process.

  • 124.
    Åberg, Jonas
    et al.
    KTH, Superseded Departments, Casting of Metals.
    Widell, Björn
    KTH, Superseded Departments, Casting of Metals.
    Bergström, Thomas
    KTH, Superseded Departments, Casting of Metals.
    Fredriksson, Hasse
    KTH, Superseded Departments, Casting of Metals.
    Measurement of intrinsic material damping using differential calorimetry on specimens under uniaxial tension2004In: Thermochimica Acta, ISSN 0040-6031, E-ISSN 1872-762X, Vol. 411, no 2, p. 125-131Article in journal (Refereed)
    Abstract [en]

    A method has been developed to measure the intrinsic damping capacity of metals. A specimen is subjected to a cyclic uniaxial stress, to give a prescribed energy input. The amount of energy that is stored in the specimen is measured using differential calorimetry, i.e. the difference in temperature between the specimen under stress and a non-stressed reference sample is measured. The experiments were performed in an insulated vacuum container to reduce convective losses. The heating rate, together with the energy input, is used as a measure of the intrinsic material damping in the specimen. The method has been developed by testing an aluminium based and a stainless steel alloy. It is possible to distinguish the difference in damping between these two alloys.

  • 125.
    Åberg, Lena Magnusson
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Vinet, Bernard
    Fredriksson, Hasse
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Heat of Solidification in Refractory Metals Studied by Drop-Tube Experiments2009In: Transactions of the Indian Institute of Metals, ISSN 0019-493X, Vol. 62, no 4-5, p. 269-273Article in journal (Other academic)
    Abstract [en]

    A number of pure refractory metals have been investigated by drop-tube experiments. The cooling curves have been registered and theoretically analysed. A model for analysing the heat of fusion has been developed. It was found that the heat of fusion was approximately 50% of the tabulated value.

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