Prototypes and small series production of metal thin-walled components is a field for the use of a number of additive technologies. This method has certain limits related to the size and price of the parts, productivity, or the type of requested material. On the other hand, conventional production methods encounter the limits of shape, which are currently associated with the implementation of optimization methods such as topological optimization or generative design. An effective solution is employing hybrid technology, which combines the advantages of 3D model printing and conventional casting production methods. This paper describes the design of aluminum casting using topological optimization and technological co-design for the purpose of switching to new manufacturing technology. It characterizes the requirements of hybrid technology for the material and properties of the model in relation to the production operations of the investment casting technology. Optical roughness measurement compares the surface quality in a standard wax model and a model obtained by additive manufacturing (AM) of polymethyl methacrylate (PMMA) using the binder jetting method. The surface quality results of the 3D printed model evaluated by measuring the surface roughness are lower than for the standard wax model; however, they still meet the requirements of prototype production technology. The measurements proved that the PMMA model has half the thermal expansion in the measured interval compared to the wax model, which was confirmed by minimal shape deviations in the dimensional analysis.

Recycling is now, more than ever, an important part of any foundry process due to the high cost of energy. The basis of the work presented here is a study of the addition of foundry scrap returns to the melt in order to reduce material and energy costs. The most important issue in such a process is the quality of both the prepared melt and final product. In this work, scrap returns were added to the AlSi9Cu3 base alloy in different proportions. Chemical composition was monitored, the solidification path was predicted by CALPHAD calculations and monitored by thermal analysis, and the formed microstructure was studied. The mechanical properties were also determined. The results showed that as the amount of scrap returns increased, elements such as Fe, Ni, Pb, Sr, etc. were more built up and elements such as Mg, Mn, Cr, etc. were decreased due to oxidation. The different chemical composition led to a reduced Mn:Fe ratio, resulting in the formation of needle-like Fe-rich phases and a decrease in mechanical properties.

Segregation of elements during solidification of massive steel castings and ingots is caused by their different solubility in the melt and in the newly formed solid phase. The macrosegregation of elements significantly affects the structure in terms of microstructure and macrostructure of the casting as well as on its mechanical and operational properties. This paper deals with the evaluation of macrosegregation of selected elements on a real cross-section of a heavy experimental carbon steel casting. Macrosegregation of elements was determined by spectral analysis at selected locations and compared with the ProCAST software and its results of casting solidification simulation. The macrosegregation was analysed along the height and width of a cross-section of the casting, which measured approximately 1800×600×100 mm. Over 300 points were analysed in this area of the casting. The results present mainly carbon segregation. The carbon segregation is compared to the solidification conditions expressed by the cooling rate and the time between the liquidus and solidus temperatures (mushy zone). The aim of this paper was also to verify the measured results with those calculated using commercial software. In conclusion, the measured macrosegregation of the carbon in the casting is different from the simulated macrosegregation, this fact is not negligible. The difference in measured carbon content is influenced by solidification kinetics and will significantly affect the material properties.

For the EN GX4CrNi13-4 martensitic stainless steel, research was conducted to investigate the impact of the quenching intensity and the content of nickel on the mechanical properties and amount of retained austenite. It was found that the amount of retained austenite significantly increases with growing nickel concentration. On the other hand, the cooling rate at quenching makes a difference only if the cooling is intensive, then amount of retained austenite decrease. A higher nickel content improves the mechanical properties. With more intensive cooling, the tensile strength decreases while the yield strength increases. The ductility is not significantly affected by the cooling intensity.