47 research outputs found

    Fizikalno modeliranje skrućivanja taline u loncu s argonskim miješanjem

    Get PDF
    The paper presents results of bath behaviour in the ladle model investigation during its gas argon bubbling realised by one or two stir elements situated in the ladle bottom. The study was performed with use of physical modelling method on a scale model 1 to 10. Development of homogenisation processes after start of bubbling was evaluated on the basis of electrical conductivity and temperature change, which were measured at three points of the ladle volume by conductivity and temperature sensors. Executed works were realised for conditions of 180 tons steel ladles.Fizikalno modeliranje skru─çivanja taline u loncu s argonskim mije┼íanjem. ─îlanak rad prikazuje rezultate eksperimentalnog istra┼żivanja pona┼íanja taline u modelu lonca s mije┼íanjem pomo─çu mjehuri─ça argona dovedenog kroz jedan ili dva mje┼ía─Źa na dnu lonca. Istra┼żivanje je provedeno koriste─çi metodu fizikalnog modeliranja na modelu u mjerilu 1 : 10. Tijek skru─çivanja (homogenizacije) nakon po─Źetka upu┼ítanja mjehuri─ça procjenjivan je temeljem promjena elektri─Źne vodljivosti i temperature, mjerenjima pomo─çu senzora vodljivosti i temeprature na tri to─Źke unutar volumena lonca. Eksperiment je proveden za uvjete lonca od 180 tona

    Anizochronn├ş model metalurgick├ęho RH procesu

    Get PDF
    RH process is a metallurgical process, which serves for vacuum treatment of liquid steel by recirculation method, which enhances quality of steel that was made either in basic oxygen converter (BOF) or in electric arc furnace (EAF). The paper presents a project and verification of appropriate physically adequate cybernetic anisochronous model of this process. This model was obtained on the basis of measured and transformed data of dimensionless concentration of model liquid in the physical model of a pouring ladle with the RH chamber, constructed in the same length (geometric) scale 1:9 to the original objects. Mathematical model will be used for optimisation of RH process under operational conditions.RH proces je metalurgick├Ż pochod, kter├Ż slou┼ż├ş k vakuov├ín├ş tekut├ę oceli recirkula─Źn├şm zp┼»sobem za ├║─Źelem zvy┼íov├ín├ş kvality oceli vyroben├ę v kysl├şkov├ęm konvertoru anebo v elektrick├ę obloukov├ę peci. V p┼Ö├şsp─Ťvku je prezentov├ín n├ívrh a ov─Ť┼Öen├ş vhodn├ęho fyzik├íln─Ť adekv├ítn├şho kybernetick├ęho anizochronn├şho modelu tohoto procesu. Uveden├Ż model byl z├şsk├ín na z├íklad─Ť nam─Ť┼Öen├Żch a transformovan├Żch ├║daj┼» bezrozm─Ťrov├ę koncentrace modelov├ę kapaliny ve fyzik├íln├şm modelu lic├ş p├ínve s RH komorou, sestrojen├Żch ve stejn├ęm d├ęlkov├ęm (geometrick├ęm) m─Ť┼Ö├ştku 1:9 k d├şlu. Matematick├Ż model bude pou┼żit k optimalizaci RH procesu v provozn├şch podm├şnk├ích

    Physical modelling of degassing process by blowing of inert gas

    Get PDF
    This paper deals with the possibilities of using physical modelling to study the degassing of metal melt during its treatment in the refining ladle. The method of inert gas blowing, so-called refining gas, presents the most common operational technology for the elimination of impurities from molten metal, e.g. for decreasing or removing the hydrogen content from liquid aluminium. This refining process presents the system of gas-liquid and its efficiency depends on the creation of fine bubbles with a high interphase surface, uniform distribution, long period of its effect in the melt, and mostly on the uniform arrangement of bubbles into the whole volume of the refining ladle. Physical modelling represents the basic method of modelling and it makes it possible to obtain information about the course of refining processes. On the basis of obtained results, it is possible to predict the behaviour of the real system during different changes in the process. The experimental part focuses on the evaluation of methodical laboratory experiments aimed at the proposal and testing of the developed methods of degassing during physical modelling. The results obtained on the basis of laboratory experiments realized on the specific physical model were discussed.Web of Science63299298

    Evaluation of the chemical composition and microcleanliness of the steel samples from the heavy forging ingot

    Get PDF
    The paper presents new results obtained from the evaluation of the chemical composition, microcleanliness and structure of the 90-ton heavy ingot cast in two successive heats, in which the content of Cu and Ni was intentionally modified in order to assess the degree of mutual mixing of the two heats in the ingot volume during the steel casting and solidification. For determination of chemical composition, spectral analysis and LECO were used. Microcleanliness evaluation was carried out on a Hitachi microanalytical complex equipped with the energy-dispersive spectrometer Vantage. To assess the composition of oxide non-metallic inclusions ternary diagrams were used. Structure of the basic steel matrix was induced by etching. The evaluation showed that in the casting of two successive heats, a certain degree of inhomogeneity of chemical composition, especially in the lower part of the ingot can be assumed in case of different composition. A greater segregation of sulphur in the central top part of the ingot was also detected. However, microcleanliness of the entire ingot is in general very good with low proportions of non-metallic inclusions.Web of Science5841167116

    Research and development of the solidification of slab ingots from special tool steels

    Get PDF
    The paper describes the research and development of casting and solidification of slab ingots from special tool steels by means of numerical modelling using the finite element method. The pre-processing, processing and post-processing phases of numerical modelling are outlined. Also, problems with determining the thermophysical properties of materials and heat transfer between the individual parts of the casting system are discussed. Based on the type of grade of tool steel, the risk of final porosity is predicted. The results allowed to improve the production technology of slab ingots, and also to verify the ratio, the chamfer and the external/internal shape of the wall of the new designed slab ingots.Web of Science6231458145

    Physical modelling of tundish slag entrainment under various technological conditions

    Get PDF
    This paper deals with the issue of physical modelling of vortexes creation and tundish slag entrainment over the mouth of the nozzle into the individual casting strands. Proper physical model is equivalent to the operational continuous casting machine No. 2 in TRINECKE ZELEZARN, a.s. Physical modelling methodology and simulated operational conditions are shortly described. Physical modelling was used for the evaluation of current conditions of steel casting at the application of different impact pads in the tundish. Further, laboratory measurement on the physical model aiming the determination of exact critical periods of vortexes creation and study of the slag entrainment as a consequence of changes in surface level during the tundish refilling to standard level were realised. The obtained results were analysed and discussed.Web of Science6231471146

    Physical and numerical modelling of a non-stationary steel flow through a subentry shroud with an inner metering nozzle

    Get PDF
    The paper presents new knowledge about physical and numerical modelling of a non-stationary steel flow into a mould through a subentry shroud with an inner, pressed metering nozzle. The physical and numerical modelling was realized under the conditions of the Department of Metallurgy and Foundry at VSB-Technical University of Ostrava. A special type of the subentry shroud is used during continuous casting of steel in T├Şineck├ę `elez├írny, a.s. During continuous casting of steel, two unfavourable phenomena were observed. In the first case, it was not possible to increase the casting speed, though the diameter of the metering nozzle was extended. In the second case, a fluctuation of the casting speed among individual casting strands was detected. These two problems did not allow an improvement of the performance of the casting machine. Therefore, the physical and numerical modelling was performed. Attention was focused on the verification of the effect of the inner diameter of the nozzle body and internal diameter of the metering nozzle on the resulting volume flow rates. Four diameters of the metering nozzle ÔÇô (16; 17; 17.5; 18) mm ÔÇô were tested. The physical modelling was done on a 1 : 1 model constructed from Plexiglas. The numerical modelling was realized in the ANSYS FLUENT software. On the basis of the results of the modelling study and in cooperation with the VESUVIUS company, a new type of the profile of the subentry shroud with a metering nozzle was designed. The first experimental results in the steel plant led to an increase in the productivity of the continuous-casting machine.Web of Science47681480

    WP┼üYW WARUNK├ôW PROWADZENIA bezpo┼Ťredniej ANALIZY termicznej NA OKRE┼ÜLENIE TEMPERATUR WYSOKO TEMPERATUROWYCH PRZEMIAN FAZOWYCH

    Get PDF
    Thermo-physical and thermodynamic properties of metallic systems represent some of the most important data that allows to describe their behaviour under strictly specified conditions. These data are the basic, input data for simulative programs, which can model this behaviour and they can be applied to real conditions. Method of direct thermal analysis is the one of the methods of enabling to obtain such data. This paper deals with application of this method on particular sample of pure standard material. The experimental laboratory system for thermal analysis Netzsch STA 449 F3 Jupiter was used for experimental measurements. This paper is studying the influence of experimental conditions on the obtained temperature of phase transformations and on shift of phase transformation temperatures with respect to the monitored experimental conditions, accuracy and credibility of the measured data. Acquired values of this data could be significantly influenced by experimental conditions, size (mass) of samples, purity of inert atmosphere and also by regimes of controlled heating and cooling rates.W┼éa┼Ťciwo┼Ťci fizyczne i termodynamiczne uk┼éad├│w metalicznych stanowi─ů jedne z najwa┼╝niejszych danych, kt├│re pozwalaj─ů opisa─ç ich zachowanie w ┼Ťci┼Ťle okre┼Ťlonych warunkach. Dane te s─ů podstawowymi danymi wej┼Ťciowymi dla programu, kt├│ry mo┼╝e symulowa─ç model tych zachowa┼ä i kt├│re mog─ů by─ç zastosowane do rzeczywistych warunk├│w. Metoda prostej (bezpo┼Ťredniej) analizy termicznej jest jedn─ů z metod pozwalaj─ůcych na uzyskanie takich danych. Niniejszy artyku┼é dotyczy zastosowania tej metody, w szczeg├│lno┼Ťci pr├│bki czystego materia┼éu standardowego. Do pomiar├│w eksperymentalnych by┼éo u┼╝ywane urz─ůdzenie dla analizy termicznej Netzsch STA 449 F3 Jupiter. W artykule analizowano wp┼éyw warunk├│w do┼Ťwiadczalnych na uzyskane temperatury przemian fazowych oraz na zmiany temperatur przemian fazowych z uwzgl─Ödnieniem monitorowanych warunk├│w do┼Ťwiadczalnych, dok┼éadno┼Ťci i wiarygodno┼Ťci danych pomiarowych. Warunki do┼Ťwiadczalne, wielko┼Ťci (masa) pr├│bek, czysto┼Ť─ç atmosfery oboj─Ötnej, a przedzia┼éy kontrolowanej szybko┼Ťci ogrzewania i ch┼éodzenia mog─ů w znacz─ůcy spos├│b wp┼éywa─ç na otrzymane warto┼Ťci tych danych.Web of Science6042871286

    Prediction of qualitative parameters of slab steel ingot using numerical modelling

    Get PDF
    The paper describes the verification of casting and solidification of heavy slab ingot weighing 40 t from tool steel by means of numerical modelling with use of a finite element method. The pre-processing, processing and post-processing phases of numerical modelling are outlined. Also, the problems with determination of the thermodynamic properties of materials and with determination of the heat transfer between the individual parts of the casting system are discussed. The final porosity, macrosegregation and the risk of cracks were predicted. The results allowed us to use the slab ingot instead of the conventional heavy steel ingot and to improve the ratio, the chamfer and the external shape of the wall of the new design of the slab ingot.Web of Science55339839

    Numerical modelling of macrosegregation in heavy steel ingot

    Get PDF
    The paper presents new knowledge and experience from numerical modelling of macrosegregation in heavy steel ingot using ProCAST software. The main aim of numerical modelling realized under the conditions of the Department of Metallurgy and Foundry and Regional Materials Science and Technology Centre at VSB-TU Ostrava is the optimization of the production of heavy steel ingots produced in V┬┤ITKOVICE HEAVY MACHINERY a.s. Input parameters of computation were determined by the real conditions of parallel experimental casting of a 90-ton steel ingot. The input data were also verified by thermal analysis and thermography measurement. The numerical results of macrosegregation were compared with the chemical analysis evaluated in a real ingot section. According to the comparison, attention will be focused next on determination of the effect of boundary conditions of filling and solidification of the ingot on the size of macrosegregation.Web of Science58117717
    corecore