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Open access

K. Miłkowska-Piszczek and J. Falkus

Abstract

This paper presents development and the application of a numerical model of the continuous steel casting process to optimise the strand solidification area. The design of the numerical model of the steel continuous casting process was presented and which was developed based on the actual dimensions of the slab continuous casting machine in ArcelorMittal Poland Unit in Kraków. The S235 steel grade and the cast strand format of 220×1280 mm were selected for the tests. Three strand casting speeds were analysed: 0.6, 0.8 and 1 m min-1. An algorithm was presented, allowing the calculation of the heat transfer coefficient values for the secondary cooling zone. In order to verify the results of numerical simulations, additional temperature measurements of the strand surface within the secondary cooling chamber were made. The ProCAST software was used to construct the numerical model of continuous casting of steel.

Open access

J. Falkus

Abstract

This paper presents research on the mould slag formed on the basis of two mould fluxes. In the conducted industrial experiments, slag was sampled in equal time intervals between adding subsequent portions of mould flux. The research focused on the an evaluation of the stability of slag parameters by assessing the change in its liquidus temperature. It was shown that a mould flux needs to be assessed individually taking into account the casting process parameters and the steel cast grade.

Open access

J. Falkus, L. Trębacz and B. Zawada

Utilization of the Steelmaking Slag By Reduction with the Use of the Modified the Chemical Composition of the Input Material

Utilization of the steelmaking slag by reduction is the technology which seems to be today rather controversial. However it is possible to use this way of utilization in case if the economical surround will be changed. One of the possible improvement for the described method is the modifying input materials for process reduction. The thermodynamic model was developed which enable to optimize the chemical composition of the final product. The laboratory investigations confirmed a good agreement between model calculations and experimental results.

Open access

T. Kargul, E. Wielgosz and J. Falkus

Abstract

Measurement of thermophysical properties of steel is possible by using different thermal analysis techniques. In the field of metallurgy the most relevant methods are Differential Thermal Analysis (DTA) and Differential Scanning Calorimetry (DSC). The paper presents the results of thermophysical properties which are necessary to carry out numerical simulation of continuous casting of steel. The study was performed for two steel grades S320GD and S235JR. The main aim of the research was to determine the dependence of specific heat on temperature. On the basis of obtained results the thermal effects of phase transformations and characteristic transition temperatures were also identified. Both the specific heat of steel and thermal effects of phase transformations are included in the Fourier-Kirchhoff equation, as the material properties necessary to obtain the numerical solution. The paper presents the research methodology, analysis of results and method of determining the specific heat of steel based on the results of DSC analysis.

Open access

M. Knap, J. Falkus, A. Rozman, K. Konopka and J. Lamut

Abstract

The objective of the research that has been presented was to model the effect of differences in chemical composition within one steel grade on hardenability, with a very broad and heterogeneous database used for studying hardness predictions. This article presents the second part of research conducted with neural networks. In the previous article [1] the most influential parameters were defined along with their weights and on the basis of these results, an improved model for predicting hardenability was developed.

These developed neural networks were applied to model predictions of hardenability for three steel grades VCNMO150, CT270 and 42CrMoS4.

The results proved that the correlation between the chemical composition differences within a chosen steel grade and the hardness changes can be modeled. If the database is big enough, predictions would be accurate and of high quality. But for a less comprehensive database, the differences in hardness predictions for various chemical compositions of the steel grade concernedwere observable.

Open access

J. Lamut, J. Falkus, B. Jurjevec and M. Knap

Influence of Inclusions Modification on Nozzle Clogging

During the secondary refining of high strength steel in a ladle furnace aluminum is used for the melt deoxidation. Aluminates inclusions are modified with a calcium silicon injection in a melt. On the basis of the binary diagram CaO-Al203 solid and liquid calcium aluminates with different composition and shape are formed after calcium treatment. During the calcium silicon injection manganese sulphide is also modified and CaS or (Ca, Mn)S is formed and wrapped around calcium aluminates.

Because of rising of calcium bubbles during the calcium silicon injection a powerful melt stirring occurs. This enables inclusion coagulation and a reaction with a slag. Additionally, the MgO·Al203 spinels are formed.

Clogging of a tundish nozzle may occur during continuous casting of steel billets. Scull which forms on the nozzle's inner wall consists of spinel, calcium aluminates with various composition and calcium manganese sulphide.

Open access

K. Miłkowska-Piszczek, M. Rywotycki, J. Falkus and K. Konopka

Abstract

This paper presents the findings of research conducted concerning the determination of thermal boundary conditions for the steel continuous casting process within the primary cooling zone. A cast slab - with dimensions of 1100 mm×220 mm - was analysed, and models described in references were compared with the authors’ model. The presented models were verified on the basis of an industrial database. The research problem was solved with the finite element method using the ProCAST software package.

Open access

J. Falkus and K. Miłkowska-Piszczek

This paper presents a strategy of the cooling parameters selection in the process of continuous steel casting. Industrial tests were performed at a slab casting machine at the Arcelor Mittal Poland Unit in Krakow. The tests covered 55 heats for 7 various steel grades. Based on the existing casting technology a numerical model of the continuous steel casting process was formulated. The numerical calculations were performed for three casting speeds - 0.6, 0.8 and 1 m min-1. An algorithm was presented that allows us to compute the values of the heat transfer coefficients for the secondary cooling zone. The correctness of the cooling parameter strategy was evaluated by inspecting the shell thickness, the length of the liquid core and the strand surface temperature. The ProCAST software package was used to construct the numerical model of continuous casting of steel.

Open access

K. Konopka, K. Miłkowska-Piszczek, L. Trębacz and J. Falkus

Abstract

The study presents the findings of research concerning the possibilities for application of parallel processing in order to reduce the computing time of numerical simulations of the steel continuous casting process. The computing efficiency for a CCS model covering the mould and a strand fragment was analysed. The calculations were performed with the ProCAST software package using the finite element method. Two computing environments were used: the PL-Grid infrastructure and cloud computing platform.

Open access

A. Burbelko, J. Falkus, W. Kapturkiewicz, K. Sołek, P. Drożdż and M. WróbeL

Modeling of the Grain Structure Formation in the Steel Continuous Ingot by Cafe Method

Computer modeling of a temperature field and a solid phase fraction in casted billets is the base of any numerical simulation of the continuous casting technology. Temperature distribution in an ingot longitudinal and cross section for the same technological parameters is a function of solidification rate and rate of the solidification heat release. Nucleation rate and solid grain growth velocity depend on a melt undercooling below the liquidus temperature, and consequently depend on a temperature value. The results of the primary grain growth and temperature distribution modeling are presented for the square steel continuous casting 160×160 mm produced by CELSA Steel Works in Ostrowiec. For the modeling the ProCAST® software was used. Virtual structure of primary grains in the continuous ingot cross section was compared with a structure of a real ingot.