Using Recycled Materials for Semi- Solid Processing of Al-Si-Mg Based Alloys

In order to reduce CO2 emission and energy consumption, more recycled secondary materials have to be used in foundry industry, especially for Al-Si-Mg based alloys for semi-solid processing. In this paper, Al-Si-Mg based alloys with the addition of recycled secondary materials up to 30 % (10, 20, 30 %, respectively) have been produced by semi-solid processing. The solidification microstructure was investigated using optical microscopy (OM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Furthermore, computed tomography (CT) was also used to elucidate the size, size distribution, number density, volume fraction of porosities. It was found that with the addition of the recycled secondary materials up to 30 %, there is no significant effect on the solidification microstructure in terms of the grain size and the shape factor of primary α-Al and the second α-Al. More importantly, the morphology of eutectic Si can be well modified and that of the Fe-containing phase (π-AlSiMgFe) can be tailored. Furthermore, with increasing recycled secondary materials, at least another two important issues should also be highlighted. Firstly, more TiB2 particles were observed, which can be due to the addition of Al-Ti-B grain refiners for the grain refinement of recycled secondary materials. Secondly, a significant interaction between Sr and P was also observed in the recycled secondary materials. The present investigation clearly demonstrates that Al-Si-Mg based alloys with the addition of recycled secondary materials at least up to 30% can be used for semi-solid processing, which may facilitate better sustainability.

Energy-Saving Technology Opportunities and Investments of the Italian Foundry Industry

The foundry industry is regarded as one of the most energy-intensive industrial sector due to its energy consumption up to 9 MWh/ton of produced metal. As a result, many companies are trying to increase the energy efficiency of their foundry plants. Since many energy-saving technologies are proposed by manufacturers and the literature, choosing the most appropriate one is a difficult task. Moreover, being updated with the available energy-saving solutions is complicated because of the quick technology advances. Consequently, this paper aims at investigating the recent and future opportunities and investments for reducing the energy consumptions of the technologies of Italian foundry companies. Additionally, it aims at presenting a list of available technological solutions validated by Italian experts. To this end, the Energy Audits developed by 231 plants were analyzed to extract the implemented and planned interventions. Furthermore, the economic data available within the Energy Audits were studied to determine the advantages of a given technological solutions compared to the others. It emerged that the companies are strongly investing in increasing the efficiency of the auxiliary systems such as compressors and motors. The outcomes of this study can assist both researchers and energy managers in choosing the most appropriate energy-saving solutions.

Reduction of Environmental Chemicals, Toxicity and Particulate Matter in Wet Scrubber Device to Achieve Zero Emissions

When fine particles generated by the foundry industry are present in the atmosphere, they have an impact on the climate because of their influence on atmospheric radioactive phenomena. As a result of this scenario, there is a rising amount of legislation restricting the emission of pollutants from foundry industries and related businesses. In response to this situation, many researchers have concentrated on end-of-pipe technologies, one of which is the wet scrubber, which is a device that is primarily used in foundries to control pollution and is one of the devices that has been incorporated. The disadvantage of using this wet scrubber, on the other hand, is that it contributes to secondary pollution when it is used. In order to combat secondary pollution, a model of an enhanced wet scrubber system that incorporates a multi-sand filtering technology was developed. The performance of this redesigned wet scrubber system was evaluated with the use of computational fluid dynamics software. Because of the introduction of the filtration tank's computation, it was discovered that successful filtration was accomplished using sand filters, meaning that environmental chemicals and particles were totally filtered from 0.17 kg at the entrance to zero kg of particles at the outflow.

Investigation on Pollution Control Device (PCD) In Foundry Industry to Reduce Environmental Chemicals

Right from the olden days, many products have been made according to foundry practices in order to generate prosperity in the societies in which they operate, while reaping these types of benefits through the operation of foundries. It is alarming that the emissions released by foundries affect human health. Therefore, foundries installed Pollution Control devices (PCDs), in accordance with this development; researchers examined the effectiveness of these PCDs in controlling emissions from foundries in different parts of the world. The emission control obtained by installing these PCDs is explained in this article based on the data gathered from the survey. The result of the study indicated that the cartridge filter built into the induction furnace achieves the best efficiency in controlling contamination from foundries. Interestingly, the operation of the cartridge filter has yet to be documented. Therefore, the construction, operation, the performance of the cartridge filter, and its efficiency in achieving contamination control in foundries are described. The article ends by emphasizing the need to conduct surveys in foundries in which a cartridge filter is installed. The results of this study will provide useful information on the use of cartridge filters in induction furnaces to reduce foundry emissions.

Thermal Properties of 3D-Printed Sand Molds

Specific heat capacity (Cp), density (ρ), and thermal conductivity (λ) of phenolic-bonded 3D-printed sand (3DPS) molds have been determined in the temperature range of 20–1400 °C using differential scanning calorimeter (DSC), dilatometer, and hot wire method. The results have been used to simulate the thermal gradient in a sand mold during casting aluminum using a commercial simulation software. The simulated results have been compared with laboratory-measured results and simulated results using the software’s database for conventional mold making. Our results show that available database for sand thermal properties cannot explain the thermal gradient in 3DPS molds and this manufacturing process affects the thermal properties of the mold compared to traditional mold making. It is necessary to collect data for a variety of 3D-printed sand molds to ensure accurate modeling simulation in the foundry industry.

Characterization of sand and sand–binder systems from the foundry industry with electrical impedance spectroscopy

The global economy consumes an estimated 4×1010 t of sand per year, with only 2×1010 t of sand being reproduced by natural sedimentation (Götze and Göbbels, 2017; Peduzzi, 2014). Among other things, sand is also used as a basic material for the production of molds and cores in the foundry industry. The consumption and the economic as well as ecological savings' potential in this area of application can be appreciated by way of an example: the environmental certificate of a single, albeit big German foundry (5160 employees) can be consulted, which states that 39 820 t of sand for casting molds had to be purchased in 2017 (Denes, 2018). In order to avoid having to dispose of the used sand in landfills and to reduce the use of new sand, it is therefore advantageous to renew the used sand in a so-called regeneration process and reuse it as a substitute for new sand in the production of molds and cores. It would be very advantageous if the condition of molding materials (sand–binder systems) in regenerator units could be monitored in real time because of the economic and ecological advantages of a monitored and optimized regeneration process. This work presents the results of investigations in this direction. The objects of investigation in this work are typical molding materials in the foundry industry, e.g., quartz sand, chromite sand, and bentonite as a binder, which are measured impedimetrically with the help of a plate capacitor measuring cell which is connected to an LCR meter (Agilent E4980A). The impedance of the filled capacitor is measured in a frequency range from 1.2 kHz to 1 MHz, containing 123 frequency points. The aim of this research is to work out if the mentioned substances can be measured with the presented measuring method and classified on the basis of impedance characteristics and thus whether impedance spectroscopy can be considered for process monitoring in the molding industry. It is shown that the condition monitoring can possibly be based on impedance spectroscopy because the resulting curves are characteristic of the material used. New and used sands as well as two-component mixtures of sands and binders showed a systematic behavior, which allows the sand or the composition of the mixture to be identified (classified) in the future. The examination of the scatter of the measurement results shows that the impedance data obtained with this method can be measured reproducibly. A descriptive model for multi-component systems is developed in order to be able to interpret the impedance scatter results and their representation in Nyquist plots. From this model, the filling density of the measurement cell and the density of conduction paths can be extracted as essential influence quantities.

Allyl glycidyl ether-modified animal glue binder for improved water resistance and bonding strength in sand casting

This paper aims to develop a modified animal glue sand binder for foundry casting with improved water resistance and bonding strength. An efficient method is reported by using sodium hydroxide as the catalyst to improve the operability of animal glue binder and allyl glycidyl ether as the modifier to improve the water resistance and bonding strength. Sand specimens prepared using allyl glycidyl ether-modified animal glue binder were cured by compressed air at room temperature. The proposed method saves energy and is environmentally friendly and inexpensive. Compared with unmodified animal glue binder, standard dog bone sand specimens with allyl glycidyl ether-modified animal glue binder had higher tensile strength of 2.58 MPa, flowability of 1.95 g, better water resistance (a lower decrease in tensile strength at 25 °C and relative humidity of 60%), and good collapsibility. This allyl glycidyl ether-modified animal glue binder is suitable for practical application in the foundry industry.