The programs WYK_Stal and Bi-Growth, developed at AGH-UST, Kraków, Poland, were used for simulating the refining process, the formation of non-metallic inclusions, and their growth. The Fe-Y-Al-O-S-Ca system in pre-oxidized steel was analyzed, where yttrium formed precipitates from both O and S. When first Al and second Y were added to steel, the proportion of Al2O3 inclusions remained constant. This resulted in higher yttrium losses for oxide formation, whereas the sulfur content promoted sulfide phase formation. The introduction of yttrium at the end of refining contributed to reducing the consumption of this element in the non-metallic phase formation. The addition of aluminum and then calcium were sufficient to achieve a high degree of deoxidation and desulfurization. Calculations performed with WYK_Stal for both (a) and (c) versions of the model showed that the sulfide phase was constituted by CaS and FeS (model c) and CaS (model (a)). The participation of the calcium sulfide phase turned out to be dominant in the inclusions. Their presence was also identified in the slag phase. Simulations of the growth of complex oxide and oxo-sulfide inclusions using the Bi_Growth program showed that the yttrium content of the steel has a decisive role in the formation of complex oxide inclusions and the final oxygen content of the steel. In contrast, for the growth of oxide-sulfide inclusions, the character of growth is determined by the sulfur content of steel.
1 December 2014 in Archives of Metallurgy and Materials
One of the most interesting categories of artifacts for archaeometallurgical research includes deposits of bronze items, so-called “metallurgists hoards”. They contain, aside of final products, many fragments of raw material and, moreover, metallurgical tools. An important source for the studies on the history of metallurgical technology is hoard from Przybysław, Greater Poland district. Thus, the aim of the work is the identification and interpretation of bronze-working practices and strategies adopted by prehistoric communities of the Late Bronze Age and the Early Iron Age (ca. 600 BC). The examined objects are characterized in terms of their design, structure, and chemical composition. The methods chosen for the studies of artifacts include: metallographic macro- and microscopic observations using optical microscopy (OM) and scanning electron microscopy (SEM), the analysis of chemical composition with the methods of energy dispersive X-ray spectroscopy (EDS), and X-ray fluorescence (ED-XRF). The thermodynamic analysis of the alloys was performed on the basis of the CALPHAD method. The experimental melts allowed to verify the theoretical considerations and to determine the characteristic temperatures of changes. The old casting technology can be analyzed basing on computer modeling and computer simulation methods. Simulations in the MAGMASOFT® software are a good example to illustrate how to fill a mould cavity with a molten bronze for a hoop ornament. It is also an appropriate tool to determine temperature distribution in a mould. The simulations also show the possible disadvantages with this old technology.
1 December 2016 in Archives of Metallurgy and Materials
The removal of non-metallic inclusions from liquid steel is a result of co-operation of fluctuation, adhesion and agglomeration effects, with emphasis on agglomeration which plays the most important role. It is based on a few types of collisions between non-metallic particles, where turbulent collisions are most prominent. As a result of agglomeration, nonmetallic inclusions are intensely removed through flotation and increase of different dimensions of inclusions, which manifests itself with the occurrence of clusters mainly composed of Al2O3precipitations. Authors investigated the agglomeration effect by making computer simulations with the use of the PSG method. The calculations were performed for a definite population of spherical particles of radiusrin the steel volume. The applied calculation method allows for analyzing the dynamics of the collision process. The assumed initial number of particles remains constant, only the number of particles in specific size-groups varies. It was also revealed that the process of agglomerates formation is much faster for particles having a bigger initial radius. In the case of very small precipitations (r=1 μm) their removal through agglomeration is very difficult because the probability those collisions can take place between them rapidly decreases.
18 September 2025 in Journal of Casting & Materials Engineering
This article presents the design process of the casting technology for a step-shaped casting made of steel using simulation tools. A series of proposals for gating and feeding systems were simulated in the MAGMASoft® software. Results of numerical simulations allowed the Authors to select the casting technology which allows defect-free casting to be obtained. A numerical analysis of the cooling rate of a step-shaped casting made of GX70CrMnSiNiMo2 tool steel with a 5% Ti addition was carried out for the selected manufacturing technology. Due to the nature of the material used and the extended presence of martensite during cooling, in-mold hardening of the casting may occur. The simulations showed that the type of molding material affects the cooling rate, which is confirmed by the analysis of cooling curves and the morphology of shrinkage porosity. The analysis of solidification rates provides a valuable starting point and basis for subsequent research stages, taking into account the actual properties of the molding sands and the phase transformations occurring in the selected steel type. The casting technology design, which ensures the production of sound casting, was developed as part of this study. A series of simulations using different molding materials confirms the significant impact that the choice of mold material has on the casting solidification and cooling process.