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The first part of presented paper is devoted to comparison of solidus and liquidus temperatures determined by two methods of thermal analysis for one real steel grade 100CrMo7. Two modern devices for high-temperature analysis were used. The direct thermal analysis method was used during an experiments realised on large samples (22 g) at NETZSCH JUPITER device. Small bearing steel samples (up to 210 mg) were studied by differential thermal analysis method at Setaram SETSYS 18TM.The robustness of both used thermo-analytical methods was documented. Measured results were compared with liquidus and solidus temperatures used in industry and calculated by specialized IDS and ThermoCalc software. Measured temperatures differ from the theoretically calculated by tens for liquidus to more than 100 °C for solidus.

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.

The work presents the results of numerical investigations of AZ31 magnesium alloy bars obtaining by the rolling process in a three high skew rolling mill. An analysis of impact the magnitude of inflicted deformation on temperature distribution in the material was made. The calculations were made using Finite Element Method (FEM) for 3D deformation state taking into account thermal phenomena that occur during applied deformation scheme. Theoretical investigations were made for two variants of deformation, one temperature of the process that equals 400 °C and four rolling rates of 25, 75 and 100 rev/min.

The article presents results of the research concerning the physical modeling of plastic working of AZ31 magnesium alloy using two research methods. These studies were conducted using a metallurgical process simulator and torsional plastometer. The research was done for temperature range 200 ÷ 400 °C and strain rate from 0,1 to 20,0 s-1, depending on the testing method. The results allow to determine the coefficients in yield equation needed for the numerical research. Moreover the most advantageous temperature - velocity conditions to realize the process of bars rolling in three high skew rolling mill can be determined.

The paper is devoted to the comparison of the results in the frame of solidus and liquidus temperatures obtained by thermo analytical methods with the generally used empirically based formulas and thermo dynamical Computherm software. The series of thermal analysis measurements of high temperature phase transformations of real steel grade (S34MnV) under conditions of two analytical devices (Netzsch STA 449 F3 Jupiter; Setaram Multi High Temperature Calorimeter (MHTC)) were carried out. Two thermo analytical methods were used (DSC and Direct Thermal Analysis). The different weight of samples was used (2,6 g; 23 g). The liquidus and solidus temperatures for close to equilibrium conditions during heating (DSC: 1 °C/min; 2 °C/min) and during cooling (Direct Thermal Analysis: 1 °C/min) were determined and compared. Then, the discussion on the different values obtained by experiments and empirically based calculation is realised.

The series of thermal analysis measurements of high temperature phase transformations of real grain oriented electrical steel grade under conditions of two analytical devices (Netzsch STA 449 F3 Jupiter; Setaram SETSYS 18TM) were carried out. Two thermo analytical methods were used (DTA and Direct thermal analysis). The different weight of samples was used (200 mg, 23 g). The stability/reproducibility of results obtained by used methodologies was verified. The liquidus and solidus temperatures for close to equilibrium conditions and during cooling (20 °C/min; 80 °C/min) were determined. It has been shown that the higher cooling rate lead to lower temperatures for start and end of solidification process of studied steel grade.

In the steel industry, a number of fluxing agents based on Al2O3 is commonly used. They are produced in different forms. This paper deals with plant results and experiences with the usage of briquetted and sintered fluxing agents for slags based on Al2O3. Proper plant heats were processed under conditions of steel plant Vítkovice heavy machinery a.s. during production of steel S34MnV by specific technology: EAF→LF→VCD. During experiments, the basic parameters influencing the steel desulphurization were monitored. Obtained results allow us to make a basic comparison of briquetted fluxing agents produced from secondary raw materials and of sintered fluxing agents, which are produced from pure raw materials.

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.

Mathematical models processed results of experimental investigation obtained during ladle gas argon bubbling realized by stir elements situated in the ladle bottom. Exact theoretical description of processes occurring at argon bubbling into steel would be very complex and it would lead to a system of non-linear partial differential equations describing transfer of momentum, heat, components, and with excitation function in the form of equation of so called deterministic chaos (argon bubbling). On the basis of pouring ladle model diagram and concentrations courses, the simplified linear physically adequate model was proposed, which described behavior of steel concentration in pouring ladle during its bubbling. The analysed process was understood in the form of a cybernetic model.

The first part of presented paper is devoted to comparison of solidus and liquidus temperatures determined by two methods of thermal analysis for one real steel grade 100CrMo7. Two modern devices for high-temperature analysis were used. The direct thermal analysis method was used during an experiments realised on large samples (22 g) at NETZSCH JUPITER device. Small bearing steel samples (up to 210 mg) were studied by differential thermal analysis method at Setaram SETSYS 18TM.The robustness of both used thermo-analytical methods was documented. Measured results were compared with liquidus and solidus temperatures used in industry and calculated by specialized IDS and ThermoCalc software. Measured temperatures differ from the theoretically calculated by tens for liquidus to more than 100 °C for solidus. [ABSTRACT FROM AUTHOR]

The article presents results of the research concerning the physical modeling of plastic working of AZ31 magnesium alloy using two research methods. These studies were conducted using a metallurgical process simulator and torsional plastometer. The research was done for temperature range 200 ÷ 400 °C and strain rate from 0,1 to 20,0 s-1, depending on the testing method. The results allow to determine the coefficients in yield equation needed for the numerical research. Moreover the most advantageous temperature - velocity conditions to realize the process of bars rolling in three high skew rolling mill can be determined. [ABSTRACT FROM AUTHOR]

The paper is devoted to the comparison of the results in the frame of solidus and liquidus temperatures obtained by thermo analytical methods with the generally used empirically based formulas and thermo dynamical Computherm software. The series of thermal analysis measurements of high temperature phase transformations of real steel grade (S34MnV) under conditions of two analytical devices (Netzsch STA 449 F3 Jupiter; Setaram Multi High Temperature Calorimeter (MHTC)) were carried out. Two thermo analytical methods were used (DSC and Direct Thermal Analysis). The different weight of samples was used (2,6 g; 23 g). The liquidus and solidus temperatures for close to equilibrium conditions during heating (DSC: 1 °C/min; 2 °C/min) and during cooling (Direct Thermal Analysis: 1 °C/min) were determined and compared. Then, the discussion on the different values obtained by experiments and empirically based calculation is realised. [ABSTRACT FROM AUTHOR]

The series of thermal analysis measurements of high temperature phase transformations of real grain oriented electrical steel grade under conditions of two analytical devices (Netzsch STA 449 F3 Jupiter; Setaram SETSYS 18TM) were carried out. Two thermo analytical methods were used (DTA and Direct thermal analysis). The different weight of samples was used (200 mg, 23 g). The stability/reproducibility of results obtained by used methodologies was verified. The liquidus and solidus temperatures for close to equilibrium conditions and during cooling (20 °C/min; 80 °C/min) were determined. It has been shown that the higher cooling rate lead to lower temperatures for start and end of solidification process of studied steel grade. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Mathematical models processed results of experimental investigation obtained during ladle gas argon bubbling realised by stir elements situated in the ladle bottom. Exact theoretical description of processes occurring at argon bubbling into steel would be very complex and it would lead to a system of non-linear partial differential equations describing transfer of momentum, heat, components, and with excitation function in the form of equation of so called deterministic chaos (argon bubbling). On the basis of pouring ladle model diagram and concentrations courses, the simplified linear physically adequate model was proposed, which described behaviour of steel concentration in pouring ladle during its bubbling. The analysed process was understood in the form of a cybernetic model. [ABSTRACT FROM AUTHOR]