The main problem during the production of castings from aluminium alloys is the presence of the reoxidation, which negatively affects the final casting quality. Liquid metal surface reacts with the ...surrounding atmosphere and oxide layer of Al2O3 is formed on its surface. The problem occurs when the oxide layer is entrained to the internal volume of the melt by turbulence and double oxide layers are formed, also known as “bifilms”. Its formation is related to the melt velocity and gating system design. In paper, naturally pressurized gating system was calculated and designed. Effect of the filter media and vortex element on the melt velocity, amount of oxides, mechanical properties, and porosity were observed. Designs with 10 ppi and 20 ppi foam filters and vortex element were compared with design without filters to prove the positive (or negative) effect of filter media on melt velocity and thus on final casting quality. The melt velocity and amount of oxides were observed with the aid of simulation software. Mechanical properties, quantity of pores, bifilm index and EDX analysis were evaluated after experimental casts. It was proven that by using 20 ppi foam filter in combination with vortex element, the best results were achieved.
This paper presents a literature review on the processing of used lithium-ion batteries in both industry and research. On an industrial scale, lithium-ion batteries are primarily processed through ...pyrometallurgical methods, leading to incomplete utilisation of lithium cells. On the other hand, the hydrometallurgical route of recycling lithium-ion batteries poses challenges, such as large-scale discharging or inert gas pretreatment, largely due to explosion hazards. Modern methods of lithium-ion battery recycling are oriented toward refining the leach liquor through solvent extraction methods using D2EHPA and Cyanex 272, to recover Co, Mn, and Ni. The final Li product is obtained through Na2CO3 precipitation.
Purpose: The purpose of the paper is to examine the impact of inward and outward foreign direct investment on innovation performance of the Visegrad and Baltic countries.Methodology/Approach: The ...study follows an open-system approach to consider the determinants of national innovation performance, taking into account both inward and outward FDI. We use two-step analysis that combines panel data regression analysis with the design of two FDI – innovation performance matrixes.Findings: The results of the study provide evidence that only outward foreign direct investment of domestic firms contributes significantly to the innovation performance of these countries and that this effect is more visible in the case of the Visegrad countries.Research Limitation/Implication: The limitations of the study are associated in particular with the selection of SII as a measure of national innovation performance. The use of this indicator is also related to the relatively short period of availability of consistent data, especially in connection with changes in the methodology of SII calculation.Originality/Value of paper: The policy implications of the paper suggest the need for stronger support of domestic bearers of cross-border capital movements in an attempt to boost national innovation performance.
Actual problem of all foundries that produce core castings with the Cold-Box-Amine methods are surface defects. Most common surface defect are burrs. Therefore it is needed to specify the ...possibilities for preventing the burrs, or make their occurrence as low as possible. According to the knowledges, the best way of eliminating the burrs is using of additives. Experiments were executed on two types of gray cast iron castings, where during preparation of mould mixture for first casting additive EP 3767/2 had been used and additive Spherox had been used for second casting. These chosen additives showed good results, surface of castings was clean, without surface defects. Given the effectiveness of selected additives only for specific types of castings, it is necessary to define the effects of these additives on the quality of the castings. For further production of flawless cast, it is necessary to describe all the possibilities of eliminating burrs.
The aim of this paper is to summarize the possibilities of foundry methods for the production of metallic foams. At present, there are a number of production technologies for this interesting ...material, to which increasing attention has been paid in recent years. What is unique about metallic foams is the combination of their physical and mechanical properties. As part of our research, we designed and verified four main methods of metallic foam production by the foundry technology, whose products are metallic foam castings with regular and irregular arrangements of internal cavities. All these methods use materials and processes commonly used in conventional foundry technologies. The main idea of the research is to highlight such technologies for the production of metallic foams that could be provided by manufacturing companies without the need to introduce changes in production. Moreover, foundry methods for the production of metallic foams have the unique advantage of being able to produce even complex shaped parts and can thus be competitive compared to today’s established technologies, the output of which is usually only a semi-finished product for further processing. This fact was the main motivation for the research.
The paper deals with the design and execution of the test of the castability into preheated plaster moulds. Castability is an important parameter for the evaluation of foundry alloys. When the metal ...does not run, it usually causes an irreparable defect in the casting. Therefore, it is necessary to verify this technological property correctly for different types of moulds. The castability test for plaster moulds and bronze is not defined, therefore The Vertical Bar Test was adopted, subsequently modified, and applied to plaster moulds. The models are made of wax and the plaster moulds are made according to the manufacturer's prescription and heated to a predetermined temperature. Copper alloy specifically CuSn10 was selected as the alloy to be investigated.
The aim of the experiment is to correctly set up and observe the parameters and the method of performing the castability test using gravity casting technology in plaster moulds. It is assumed, as the casting temperature increases, the run-in length of the metal alloy will increase. An important goal is to obtain relevant results, as many variables affect the progress of the test and so there is a risk of error. Due to the time-consuming nature of producing a real disposable model and mould, any failure to succeed would have an economic impact on the foundry, affecting the price of castings. The new method for evaluating castability in plaster moulds can be applied to other types of alloys when temperature changes occur.
•Design of a modified castability test.•The use of CuSn10 alloy as a representative of the most popular used copper alloy.•Application on plaster moulds.•Finding relationships between measured values.•Description conclusions.
The paper presents the results of research that is focused on the renovation of molds for high-pressure aluminum casting. An analysis of the worn molds was carried out after they were removed from ...the operator. The extent and mechanism of the wear were determined. GTAW (Gas tungsten arc welding) technology was chosen for the renovation of the shaped parts of the molds. The renovation layers were realized with four types of additional materials Cronitex RC 44, UTP A 73 G 3, UTP A 673 and Dievar® TIG. The quality of the coatings was assessed by destructive as well as non-destructive tests. The mixing of the build-up layers with the base material was determined on the basis of structural analyses. The hardness of the cladding was determined by a metallographic analysis of the cross crowns with the Vickers method. The resistance of the cladding was tested by a complete immersion in a melt of AlSi8Cu3 aluminum alloy which was maintained at a temperature of 680 ± 20 °C in a laboratory resistance furnace for 120 and 300 min. The tribological properties of the produced deposits were determined using the ball-on-disc dry method. Based on the experiments that were carried out, it is possible to recommend the additive material UTP A 73 G 3 for the restoration of the functional surfaces of molds for the injection of Al alloys as the patterns that were created by it have shown the best results in terms of their resistance to Al melt, which is the dominant degradation factor limiting the life of the molds.
The automotive industry is one of the most important customers for the foundry industry. In particular, casting of engine parts for combustion engines is one of the most demanding areas of casting ...technology. New generation of engine blocks and cylinder heads are getting geometrically more complicated in order to maintain or even increase performance. With the increased complexity, the strain for the casting molds is growing and the widely used technology of core making with standard silica sands is, for several applications, no longer reaching the demanded results. Furthermore, in last decade, there has been an effort in using inorganic binders in core making process, which brings along some additional technological challenges. In order to cope with these challenges, in this paper, silica and non-silica sands with round and angular grains as well as with fine and coarse grains are examined using an inorganic binder for strength, permeability, and thermal stability. The results shall provide useful information about the possibilities of application and combining different types of foundry sands, both silica and non-silica. With their impact on the selected sand core properties, they can help in solving problems in the core making process as well as reaching a high quality of the final product-casting.
The influence of the processing route on the microstructure characteristics and mechanical properties of high-entropy carbides was investigated. The experimental materials were prepared by a ...combination of ball milling and spark plasma sintering at the temperature of 2100 °C. The effect of sintering time (5 min, 10 min, and 20 min) on the microstructure development and properties of the investigated systems has been studied. The microstructure analysis was performed using scanning electron microscopy + EDAX analysis on the polished surfaces. Nanoindentation was used for the nano-hardness and Young’s modulus measurements. Micro-hardness was measured using Vickers method and indentation method using a Vickers indenter was used to determine the indentation fracture resistance – fracture toughness. The measured grain size values were in the range from 5 µm to 14 µm. The nano-hardness values changed from 36 GPa to 39 GPa and the indentation modulus of elasticity from 558 GPa to 577 GPa, respectively. The measured micro-hardness values were in the range from 18.93 GPa to 21.95 GPa and the indentation fracture resistance changed from 2.70 MPa.m1/2 to 3.50 MPa.m1/2, respectively.
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