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.Keywords: continuous casting of steel, numerical modelling, optimization technological parameters, metallurgical length W pracy przedstawiono zastosowanie numerycznego modelu procesu COS do optymalizacji obszaru krzepnięcia pasma. Zaprezentowano budowę numerycznego modelu procesu ciągłego odlewania stali, który opracowany został na podstawie rzeczywistych wymiarów maszyny do odlewania wlewków płaskich w Arcelor Mittal Poland Oddział Kraków. Do badań wybrano gatunek stali S235 przy odlewanym formacie wlewków 220×1280 mm. Analizowano trzy prędkości odlewania wlewka: 0.6, 0.8 oraz 1 m min −1 . Zaprezentowano algorytm pozwalający obliczyć wartości współczynników wymiany ciepła dla strefy wtórne-go chłodzenia wraz z możliwością wyznaczenia natężenia przepływu w poszczególnych strefach natrysku. W celu weryfikacji wyników symulacji numerycznych przeprowadzono dodatkowe pomiary temperatury powierzchni pasma w komorze wtórnego chłodzenia. Do budowy numerycznego modelu COS wykorzystano pakiet oprogramowania ProCAST.

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 mmwas 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.Keywords: continuous casting of steel, heat transfer coefficient, numerical modelling, ProCAST W pracy przedstawiono wyniki badań dotyczących wyznaczenia termicznych warunków brzegowych dla procesu ciągłego odlewania stali w obszarze strefy pierwotnego chłodzenia. Analizie poddano wlewek płaski o wymiarach 1100×220 mm. W obliczeniach porównano modele opisane w literaturze wraz z modelem własnym. Zaprezentowane modele zweryfikowano na podstawie przemysłowej bazy danych. Zadanie zostało rozwiązane metodą elementów skończonych z zastosowaniem pakietu oprogramowania ProCAST.

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 R software was used. Virtual structure of primary grains in the continuous ingot cross section was compared with a structure of a real ingot.Keywords: ProCAST, structure, solidification, continuous casting, modelingPodstawą modelowania matematycznego procesu ciągłego odlewania stali (COS) jest symulacja komputerowa pola temperatury i składu fazowego w obszarze wlewka. Rozkład temperatury wzdłuż wlewka i w jego przekroju przy zadanych parametrach odlewania zależy m.in. od intensywności przemiany fazowej, której towarzyszy wydzielanie się ciepła krystalizacji. Szybkości zarodkowania i wzrostu ziaren fazy stałej z ciekłej stali są uzależnione od jej przechłodzenia poniżej temperatury likwidus, a więc, w sposób pośredni od wartości temperatury. W pracy przedstawiono wyniki modelowania pola temperatury i procesu tworzenia się struktury pierwotnej stali B500 SP podczas krzepnięcia wlewka ciągłego o przekroju 160×160 mm, odlewanego w warunkach CELSA HUTA OSTROWIEC. Do celów modelowania wykorzystano oprogramowanie ProCAST. Uzyskaną w symulacji strukturę ziaren pierwotnych w przekroju poprzecznym skonfrontowano z wynikami badań struktury rzeczywistej przekroju poprzecznego wlewków kwadratowych. Mathematical modeling of the continuous casting solidificationIn the earlier papers about the heat transfer in a continuous casting ingot the numerical solutions of the Fourier (or Fourier-Kirchhoff) partial differential equations were used [1][2][3][4][5][6][7][8][9][10][11]. For the numerical solution the Euler meshes were used. This kind of computational mesh is fixed in space. That is why additional calculations are needed to describe quantitatively the convectional heat transport generated by the movement of an ingot solid part in a stationary coordinate system connected with an installation. The phenomena of the grain nucleation and growth in the aforementioned publications are not taken into account.The attempts of the microstructure formation modeling in the continuous casting as results of the grains nucleation and growth are shown in [12,13]. The so-called micro-macro model was used in these papers. In the micro-macro modeling the heat transfer process was analyzed in scale of an ingot (macro). Mathematical model of the nucleation and growth of solid grains in the micro-scale make it possible to predict the s...

Materials based on Ni-Co-Fe alloys, due to their excellent magnetic properties, attract great attention in nanotechnology, especially as candidates for high-density magnetic recording media and other applications from spintronic to consumer electronics. In this study, Ni-Co-Fe nanocrystalline coatings were electrodeposited from citrate-sulfate baths with the Ni2+:Co2+:Fe2+ ion concentration ratios equal to 15:1:1, 15:2:1, and 15:4:1. The effect of the composition of the bath on the morphology, microstructure, chemical composition, microhardness, and magnetic properties of the coatings was examined. Scanning (SEM) and transmission (TEM) electron microscopy, X-ray diffractometry (XRD), and energy dispersive X-ray spectroscopy (EDS) were used to study surface morphology, microstructure, chemical, and phase composition. Isothermal cross-sections of the Ni-Co-Fe ternary equilibrium system for the temperature of 50 °C and 600 °C were generated using the FactSage package. Magnetic properties were analyzed by a superconducting quantum interference device magnetometer (SQUID). All the coatings were composed of a single phase being face-centered cubic (fcc) solid solution. They were characterized by a smooth surface with globular morphology and a nanocrystalline structure of grain diameter below 30 nm. It was determined that Ni-Co-Fe coatings exhibit high hardness above 4.2 GPa. The measurements of hysteresis loops showed a significant value of magnetization saturation and small coercivity. The microstructure and properties of the obtained nanocrystalline coatings are interesting in terms of their future use in micromechanical devices (MEMS).

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.