The paper presents analysis of phase transformation temperatures of 20MnCr5 steel. For calculations of required temperatures, i.e. liquidus temperature (TL) and solidus temperature (TS) was used CompuTherm thermodynamic database. The aim of this paper was the use calculated temperatures from CompuTherm thermodynamic database to design regression equations for calculation of the phase transformation temperatures. From the results it is obvious that in the calculation of individual temperatures, the chemical composition has a significant effect on changes of the values of given temperatures. The resulting temperatures also vary depending on the used calculation method (the Lever method proved to be the most suitable). The mean value of liquidus temperature is 1,508 °C and the solidus temperature is 1,462 °C (using CompuTherm and the Lever method). The range of the two-phase zone region for the average content of elements within the limits of 20MnCr5 steel grade is thus 46 °C. Furthermore, the resulting regression equations are given in the work, determined by regression analysis of 66 possible variants of chemical composition of steel 20MnCr5 phase transformation temperatures calculated for defined chemical compositions by thermodynamic database CompuTherm. These equations can be used in operational conditions for calculations of phase transformations in the limit values of the used chemical composition of a given steel grade. When using a different range of chemical composition, these equations can be used, but without guaranteed results.

The article will deal with the determination of austenite decomposition temperatures using the available SW FactSage. The determination of austenite decomposition temperatures is one of the basic information that can provide the technologist and subsequently help to change the properties of steel during steel processing. Austenite is one of the interstitial carbon solutions. Austenite is characterized by a cubic area-centered lattice and its structure is formed by regular grains. Various phases or structural components may form during cooling of austenite. Depending on the cooling of the steel, perlite, bainite and martensite may be formed. During the cooling of the steel, the area-centered lattice changes to a spatially centered iron lattice alfa. The aim of the presented work will be to determine the decomposition temperatures of austenite in 41Cr4 steel.

The subject of this paper is the analysis of phase transformation temperatures, specifically liquidus temperature (TL) for steel quality 41Cr4. To calculate the temperatures, 66 different variants of the chemical composition of a given steel grade were compiled. The calculations were performed in the CompuTherm thermodynamic database using the Lever microsegregation model. The resulting temperatures are further supplemented by multiple regression analysis, which considers the dependence on the chemical temperature. The results of the regression analysis are used to design a regression equation to calculate the liquidus temperature. It is clear from the obtained results that the chemical composition of the steel has a significant temperature effect on the change in the calculated values.

This work aims to assess the effect of an oxygen content graded in minimal quantities, on the order of hundreds of ppms, on the determination of surface tension of low-alloy FeCOCr and FeCONi steels in contact with a corundum substrate. Oxygen, as a surface-active element, was segregated at the surface where it interacted with the major components of the alloys, leading to a reduction in surface tension. The sessile drop method was used for wetting tests in the temperature range from steel liquidus temperatures to 1600 °C under nonoxidizing conditions. The effect of oxygen on surface tension and wetting angles was verified by statistical analysis using the Kruskal–Wallis test, which supported the results stating that the values of these quantities decreased with increasing oxygen content. Furthermore, liquidus temperatures, which are of practical importance, were determined by the optical and DTA methods and then compared with theoretically calculated temperature values. It turned out that the increased chromium content causes difficulties in determining surface tension up to 1550 °C due to the formation of a thin Cr2O3 layer. In addition, SEM and XRD analyses accompanied by calculations in the FactSage oxide database were performed to better understand the wetting mechanism.

This investigation was carried out to determine the wetting characteristics of low alloy steel grades that contained, among other elements, chromium around 5 wt.% and oxygen up to approximately 400 ppm. The tests were performed from the melting temperature to a temperature of 1,600 °C using a high-temperature observation furnace CLASIC operating under non-oxidizing conditions. The influence of oxygen on the examined steel's wetting behavior, i.e., the temperature dependence of surface tension and wetting angle, was found and verified by statistical analysis using the Kruskal-Wallis test. In addition, the phase transition temperatures, ascertained from DTA measurements, were in strong correlation with those theoretically calculated. To provide better insight into the wetting mechanism, SEM/EDX analyses of the wetted alumina surface and of the vertical cross-section of the steel/alumina interface were made using a scanning electron microscope (SEM) JEOL 6490 LV. Beyond the mentioned techniques, the study was accompanied by calculations performed in FactSage oxide database.