Differential scanning calorimetric (DSC) measurements to identify high-temperature phase transitions of two non-alloyed peritectic steel grades are presented and discussed in this paper. Netzsch STA 449 F3 Jupiter thermal analyser device was used to perform DSC experiments. Measurements of temperatures of phase transformations at the heating and cooling rates of 5 and 20°C min -1 were conducted. Measurement conditions for determining the temperature of peritectic transition in two real steels grades were described. The influence of measurement conditions on the results of DSC analysis was discussed. It was found that heating rate slightly affects the temperature of peritectic phase transition. Experimentally obtained solidus and liquidus temperatures are in good agreement with values derived by numerical calculations using FactSage software with database developed by Scientific Group Thermodata Europe. New original data (phase-transition temperatures) were obtained in this study, which may, however, be used for modelling of the solidification behaviour of peritectic steel grades.

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.Keywords: thermal analysis of steel, specific heat, enthalpy of phase transitions, steel Pomiar właściwości termofizycznych stali możliwy jest dzięki wykorzystaniu różnych technik analizy termicznej. W metalurgii najszersze zastosowanie znalazły różnicowa analiza termiczna (DTA) oraz różnicowa kalorymetria skaningowa (DSC). W pracy przedstawiono wyniki badań właściwości termofizycznych koniecznych do przeprowadzenia symulacji numerycznej procesu ciągłego odlewania stali. Badania wykonano dla dwóch gatunków stali S320GD i S235JR. Głównym celem badań było wyznaczenie funkcyjnej zależności ciepła właściwego analizowanych gatunków stali od temperatury. Na podstawie przeprowadzonych badań określono również efekty cieplne przemian fazowych oraz charakterystyczne temperatury przemian. Zarówno ciepło właściwe stali jak i efekty cieplne przemian fazowych wchodzą w skład równania Fouriera-Kirchhoffa, jako właściwości materiałowe konieczne do uzyskania rozwiązania numerycznego. W pracy przedstawiono metodykę badań, analizę uzyskanych wyników oraz sposób wyznaczania ciepła właściwego stali w oparciu wyniki analizy DSC.

The paper presents the concept of a new mathematical model, which has been used for the simulation of the ladle furnace steel refining process. The structure of the model contains a mathematical description of the steel stirring processes caused by the injection of argon and a thermodynamic description of the reactions occurring at the metal‐slag interface. Both models have been combined into a single hybrid model, using the SimuSage package. The hybrid model has served as the basis for the creation of a proprietary simulation tool, which has been used to assess the effectiveness of the metal bath desulfurization process in the ladle furnace. The applied mathematical description of the processes occurring in the ladle furnace enables the process simulation to be carried out in real time. The constructed model has been verified in industrial conditions for a ladle furnace of 140 t capacity.

The paper presents the results of DSC analysis of steel B500SP produced in the process of continuous casting, which is intended for the production reinforcement rods with high ductility. Studies were carried out in the temperature range below 1000°C in a protective atmosphere of helium during samples heating program. The main objective of the study was to determine the temperature range of austenite structure formation during heating. As a result of performed experiments: Ac 1s , Ac 1f -temperatures of the beginning and finish of the eutectoid transformation, Ac 2 -Curie temperature of the ferrite magnetic transformation and the temperature Ac 3 of transformation of proeutectoid ferrite into austenite were elaborated. Experimental determination of phase transformations temperatures of steel B500SP has great importance for production technology of reinforcement rods, because good mechanical properties of rods are formed by the special thermal treatment in Tempcore process.

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