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Additive manufacturing offers great potential for various industrial solutions; in particular, the binder jetting method enables the production of components from various materials, including sand molds for casting. This work presents the results of an extensive set of experiments aimed at enhancing the structural strengthening of 3D-printed sand molds. Structural strengthening was achieved by impregnating the sand-printed structures with two polymer materials: epoxy resin and silicone varnish. Impregnation was performed with variable parameters, such as temperature, pressure, and time. Structural strengthening using polymers was investigated by analyzing the flexural strength and impact resistance of the impregnated products and comparing these obtained values with the reference material in terms of impregnation parameters and the polymer used. Microstructural observations and an analysis of the pore filling were also performed. This approach allowed for a full assessment of the influence of processing parameters and the type of polymer used for impregnation on the properties of sand-printed structures, which allowed for identifying the most optimal method to be used to strengthen the sand molds for casting the components for electrical devices. As a direct proof of concept, it was shown that impregnation with polymeric materials could effectively strengthen the sand mold, increasing its flexural strength and impact resistance by over 20 times and 5 times, respectively. A full-scale mold was printed using binder jetting, impregnated with epoxy resin at 65 °C, and used to successfully fabricate a fully functional electrification device. [ABSTRACT FROM AUTHOR]

Nowadays, with the development of electromobility, the requirements not only for the mechanical properties but also for the thermal conductivity of castings are increasing. This paper investigates the influence of casting and heat treatment technology on the thermal diffusivity and thermal conductivity of an AlSi10MnMg alloy. The thermal diffusivity was monitored as a function of temperature in the range of 50–300 °C for the material cast by high-pressure die casting (HPDC) and also by gravity sand casting (GSC) and gravity die casting (GDC). This study also investigated the effect of the T5 heat treatment temperature (artificial ageing without prior solution treatment—HT200, HT300, and HT400) on the thermal conductivity of the material cast by different technologies. Experiments confirmed that the thermal diffusivity or thermal conductivity of the alloy depends on the casting technology. The slower the cooling rate of the casting, the higher the thermal conductivity value. For the alloy in the as-cast condition, the thermal conductivity at 50 °C is in the range of about 125 to 138 [W·m−1·K−1]. Regardless of the casting method, the thermal conductivity tends to increase with temperature (50–300 °C). Furthermore, a positive effect of heat treatment without prior solution treatment (HT200, HT300, and HT400) on the thermal conductivity was demonstrated. Regardless of the casting method of the samples, the thermal conductivity also increases with increasing heat treatment temperature. The results further showed that when artificial ageing is performed in industrial practice on castings to increase mechanical properties in the temperature range of 160–230 °C, this heat treatment has a positive effect on thermal conductivity. [ABSTRACT FROM AUTHOR]

The latest generation of high-performance cylinder blocks are produced with the Precision Sand Castings Process which sometimes uses a monolithic cast iron chill that promotes enhanced solidification conditions that improve both tensile and fatigue performance. However, monolithic chills tend to be re-used quite quickly and thus can be significantly above room temperature during the next subsequent casting. To deter the potential deleterious effects, this may cause most casting practitioners to enforce a strict room temperature condition of the chill prior to use. However, this may necessitate a higher number of chills in the system or the implementation of chill cooling stations, both of which involve higher capital investment. The authors will address the most optimal method to address thermal management of chills by documenting the mechanical and microstructural property impact and its compliance in the bulkhead (next to chill) and head bolt columns (60 mm away from the chill) to the chill temperature prior to casting. The Quality Index will reflect the chill temperature impacts based on the mechanical properties results for this manuscript. [ABSTRACT FROM AUTHOR]

In a comprehensive study, effects of casting methods such as gravity sand casting, squeeze casting and composite casting in semi-solid state and casting variables (i.e., cooling rate, stirring speed and shear forces) on the microstructure, porosity formation and mechanical properties of A356–SiC nanocomposites were investigated thoroughly. First, a step-like sample was used to make the sand casting samples to study the effects of different cooling rates that each step experienced on the properties of nanocomposite, where squeeze casting and composite casting samples were produced in a metallic mold. Once the samples were produced and prepared for the studies, grain size, shape factor, dendritic and globular microstructure, amount of eutectic phase and mechanism of porosity formation, mechanical properties and fracture surface of the samples were analyzed precisely and discussed. In addition, the effects of stirring forces, time and temperature, used in the squeeze casting and the compo-casting methods, on the morphology of the dendritic arms of aluminum matrix composites were investigated and compared with the microstructure of castings produced by conventional gravity casting. It was discovered that switching from the gravity sand casting process to the squeeze casting process delivers a less dendritic and more refined microstructure in the nanocomposite. However, composite castings produced in the semi-solid state by applying high stirring shear forces for 80 s produce the finest and the most globular and spherical microstructure. This optimized globularization condition provides desired microstructure and mechanical properties for this type of nanocomposite. The dominant failure mechanism in the composite casting samples produced in semi-solid state was ductile, where it was a mix of ductile/brittle for the squeeze casting and brittle for the sand casting samples. Finally, the effects of globularization temperature on the nucleation and growth of primary α grains were studied. [ABSTRACT FROM AUTHOR]

The unclear contraction behavior of Mg-Gd-Y-Zr alloy during low-pressure sand casting bring obstructs into the dimensional control in the fabrication of large and complex parts, restricting the further engineering applications of this alloy. This paper investigated the rule for free and constrained contraction of typical Mg-Gd-Y-Zr (Mg-9Gd-3Y-0.5Zr, VW93K) alloy during low-pressure sand casting. A series of castings with different volumes and geometric structures were designed and a 3D scanner was employed to measure different types of dimensions, which were then used for the calculation of contraction coefficients. The convergent value of free contraction coefficients was derived through statistical analysis, and the correlation between constrained contraction coefficients and geometric characteristics of castings was established by the utilizing of core volume factor. In the condition of low-pressure casting, free contraction coefficients of VW93 alloy are concentrated around a fixed value of 1.72%, constrained contraction coefficients of VW93 alloy show a decreasing linear tendency against core volume factor, and pouring pressure makes effects on free contraction. The experimental results and proposed formulas provide guidance for accurate dimensional control in fabrication of large and complex Mg-RE alloy parts by low-pressure sand casting. [ABSTRACT FROM AUTHOR]

In the foundry industry, casting sand cores require high and low peak and residual strengths, respectively, to achieve comprehensive optimal mechanical performance. The peak and residual strengths of sand cores are positively related, highlighting the criticality of balancing them. Thus, an innovative approach comprising the incorporation of anionic surfactants into the silicate binder was introduced to balance both factors. Additionally, the investigation of the effects of the anionic surfactants on the physical properties of the silicate binder, including its colloidal stability, surface tension and adhesion, revealed that four different anionic surfactants reduced the surface tension and adhesion of the silicate binders and reduced the residual strength of the silicate-bonded sand cores. Among them, 0.10 wt% lauryl ether phosphate reduced the surface tension and adhesion of the adhesive by 49.64 and 112 mN/m, respectively, and reduced the residual strength of the sand core by 0.035 MPa. However, increasing the dosage did not further reduce the residual strength of the sand core, although it continued to reduce its peak strength. Therefore, during silicate binder modification with anionic surfactants, the dosage of the anionic surfactant must be kept at ≤0.10 wt%, as this dosage exerted the most comprehensive optimal modification effect, which was attributable to the adsorption of anionic polymers onto the surface of the silicate aggregates. This adsorption weakened the network structure of the silicate aggregates and imparted the sand cores with appropriate mechanical properties during casting. [ABSTRACT FROM AUTHOR]

Addressing the significant issues of sand burn-on defects and interfacial reaction in sand casted 13Cr9Mo1VNb steel castings, which notably compromise the quality of the steel castings, remains a persistent challenge. The interfacial behaviors between the novel mixed sands and the steel grade were investigated under various sands. The sintering behavior of the sands was also studied without liquid steel at various holding time. In the absence of the influence of molten steel, sintering of mixed chromite-MgO does not undergo solid-solid reaction, with no detected presence of liquid phase and 2MgO·SiO 2. The mixed sands undergo sintering reactions upon contact with molten steel, yet no liquid phase is detected. This is primarily attributed to the chemical reaction between MgO and the liquid phase, resulting in the formation of forsterite, leading to the near-complete liquid phase consumption. Magnesia grains can suppress the liquid phase sintering of chromite by 13Cr9Mo1VNb, thus weakening its sintering performance. The presence of 2MgO·SiO 2 , which exhibits excellent resistance to slag (liquid phase) and steel liquid corrosion, impedes the rising of the liquid phase. Consequently, this reduces the thickness of the adhesive layer and suppresses metal penetration. The production of 2MgO·SiO 2 diminishes with the escalation of MgO addition, which increases adhesive thickness and metal penetration as the magnesia content rises. Within the scope of this study, the incorporation of 20 % MgO is suggested to mitigate burn-on defects, which may represent an advantageous selection. [ABSTRACT FROM AUTHOR]

The International Journal of Metalcasting highlights research projects funded by the American Foundry Society (AFS) that aim to support the metalcasting industry in North America. These projects cover a range of topics, including new technology, improved processes, and knowledge transfer. Specific projects include developing digital tools for accessing metalcasting best practices, investigating new materials and processes for investment casting, and studying the effects of different materials on the mechanical properties of cast iron. The AFS also collaborates with other organizations on projects related to additive manufacturing and improving casting quality. In addition to funding research, the AFS offers various resources and services for individuals in the metalcasting industry. Their website provides tools for selecting casting processes and alloy properties, as well as a directory of metalcasters. AFS also offers a social network called Casting Connection and an online library with access to technical articles and reports. They host conferences, workshops, and webinars on topics related to metalcasting, and they have a mobile app for accessing their library resources. [Extracted from the article]

Permanent mold (PM) and semi-solid (rheo) casting in ductile iron castings (DIC) were studied, and the microstructure was aimed to be chill free in as-cast condition. Denitrification was conducted understanding solubility properties of nitrogen in base molten iron, and re-nitrification was strictly avoided during molten treatment by Mg alloy. As the results, chill-free knuckle castings were possible with both casting methods in as-cast condition. The knuckle castings had no shrinkage cavity also. The solidification time by rheocasting was shorter than that of PM casting. It was approximately one in two and a half. The castings had ultrafine spheroidal graphite which were mostly under 10 µm. The graphite structure by rheocasing method was finer and more uniform than those of PM casting. The tensile strength in castings with both casting methods was approximately 1.3 times keeping elongation over 10% comparing with conventional sand knuckle castings. It was concluded that free nitrogen (NF) promoted chill formation, and chill could be avoided by promoting denitrification and minimum re-nitrification. [ABSTRACT FROM AUTHOR]

In recent development of casting traceability, it has been noticed that many casting manufacturing processes that involve the use of sand cores often lack proper traceability back to the cores used in their production and the supporting production information. Most marking symbols applied to sand cores using existing marking methods not only exhibit unstable code readability but also pose critical risks to the surface quality of sand cores. In response, we developed and tested a digital-twin core rack aimed at transferring digital codes to sand cores without contact with their surfaces. By utilizing infrared sensors for real-time object detection, the core rack can transfer digital identical codes from the core-making machine to the core rack, and subsequently to the casting machine. This digital code encompasses all relevant process data of a sand core, from core making to de-coring. Moreover, the various sensors embedded in the core rack were designed to monitor air humidity, temperature, and vibration events during the transport and storage of the cores. These parameters are especially critical for maintaining the quality of inorganic sand cores. The study demonstrates the successful application of each component within this conceptual framework. Looking ahead, it is imperative to update the hardware of this concept to ensure its adaptation to the demanding conditions of an industrial environment. [ABSTRACT FROM AUTHOR]

An evaluation method for the initial penetration of molten cast iron into the sand mold was suggested based on the laboratory-scale penetration experiments for the cast iron. The horizontal penetration depth of the molten cast iron into the sand core was analyzed using the capillary model. The early stage of the penetration was discussed, and it was clarified that the penetration is not stopped by the solidification but is stopped by the decreasing of the equivalent pore radius. It was explained that the equivalent pore radius decreases with increasing the penetration depth, and the penetration is stopped when the critical pressure, i.e., the pressure required for the penetration, becomes higher than the pressure which is acting on the penetration front. Based on the analysis, an evaluation method of the penetration of depth at the early stage of the penetration was suggested. The analysis method was applied for the other type of metals (mercury and steel) as well, and reasonable results were obtained. A simplified finite-element model of liquid iron penetration into a sand core was developed, accounting for heat exchange between the melt and the porous medium, at different pore geometries. [ABSTRACT FROM AUTHOR]

The important supporting component in a gas turbine is the casing, which has the characteristics of large size, complex structure, and thin wall. In the context of existing 3DP sand casting processes, casting crack defects are prone to occur. This leads to an increase in the scrap rate of casings, causing significant resource wastage. Additionally, the presence of cracks poses a significant safety hazard after the casings are put into service. The generation of different types of crack defects in stainless steel casings is closely related to casting stress and the high-temperature concession of the sand mold. Therefore, the types and causes of cracks in stainless steel casing products, based on their structural characteristics, were systematically analyzed. Various sand molds with different internal topology designs were printed using the 3DP technology to investigate the impact of sand mold structures on high-temperature concession. The optimal sand mold structure was used to cast casings, and the crack suppression effect was verified by analyzing its eddy current testing results. The experimental results indicate that the skeleton structure has an excellent effect on suppressing cracks in the casing. This research holds important theoretical and engineering significance in improving the quality of casing castings and reducing production costs. [ABSTRACT FROM AUTHOR]

The object of research is the technology of manufacturing «Body»-type shaped castings of the from medium carbon steel in one-time sand molds. The existing problem is that the design of the casting and foundry equipment significantly affect the formation of internal defects in castings. This especially applies to steel castings, the technology of which is more complicated than the technology of cast iron castings due to much worse casting properties of steel. To determine the influence of the location of surpluses on the «Body»-type steel castings of the on the formation of shrinkage shells, computer modeling was used, in the process of which 5 computer experiments were conducted with different sizes and geometries of surpluses. According to the simulation results, it was found that with some technological options, there is a risk of the shrinkage shell penetrating into the casting body. The use of a cylindrical surplus of a rectangular cross-section with fillets ensures complete absorption of the shrink shell in the place of surplus installation. Using an excess round section at the installation location does not guarantee absorption of the shrink shell. The determining factor affecting the coefficient of increase in the depth of the shrinking shell is the excess volume. This influence can be described by a functional dependence of the logarithmic type with the coefficient of determination R2 = 0.82. It was determined that the ratio of the diameter of the inlet to its height does not affect the coefficient of increase in the depth of the shrinking shell. The resulting functional dependence allows to set the excess volume that provides a minimum growth factor while simultaneously preventing excess metal consumption. The presented study will be useful for machine-building enterprises that have foundries in their structure, where shaped castings are made in one-time sand molds. [ABSTRACT FROM AUTHOR]

The International Journal of Metalcasting provides information on the funding and involvement of the American Foundry Society (AFS) in metalcasting research projects. AFS collaborates with government funding, industry contributions, and other means to support research in the metalcasting industry. They are currently involved in partnerships such as the American Metalcasting Consortium (AMC) funded by the Defense Logistics Agency (DLA). AFS also funds research projects on various topics including virtual knowledge transfer platforms, cost-effective fast response and sustainability for critical castings, and refining austenite in gray irons. The text also mentions resources like the AFS Casting Alloy Data Search and the Peters-Robison AFS Metalcasting Library, as well as upcoming conferences and workshops organized by AFS. [Extracted from the article]

The influence of external magnetic field in the sand casting process on the microstructures and mechanical properties of A357 aluminum-silicon (Al–Si) alloys was investigated. Different magnetic field intensities such as 0, 6.3, and 10.7 mT were applied respectively by Helmholtz coils with an autotransformer. Applied an external magnetic fields during the solidification process, the microstructures of as-cast A357 alloy performed grain refinement of α-Al, reduction of secondary dendritic arm spacing, and fibrous structure of eutectic silicon. After T6 heat treatment, the morphology of eutectic silicon particles became fragmented and spheroidized. Therefore, the magnetic field enhanced the mechanical properties of A357 alloys, including hardness, ultimate tensile strength (UTS), yield strength (YS), and elongation (El). Compared the samples without magnetic field and with the field of 10.7 mT, the values of hardness, UTS, YS and El increased 17.9%, 10.6%, 8.8%, and 48%, respectively. The higher the magnetic field we apply, the better performance of sand-cast A357 we can get. Moreover, the magnetic field during A357 solidification process attributed to the preferred orientation (111) of α-Al and uniformly dimples in fractography. In conclusion, an inexpensive and facile technique has been proposed to enhance the quality index of the sand-casting A357 alloys via the influence by external magnetic fields on the microscopic properties of materials, especially for α-Al grain refinement and eutectic-silicon spheroidization. [ABSTRACT FROM AUTHOR]

The process of ablation casting (AC) is a novel sand casting technique that not only offers the benefits of conventional sand casting (CSC), but also offers opportunities to overcome some of its shortcomings. In this research, A413 and A356 alloys were cast via CSC and AC processes. The CSC simulation process showed that the solid fraction parameter at different times indicated A413 to be more suitable than A356 for the AC process. The experimental results showed that AC process increased the cooling rate of both alloys (4–6% times for A413 and 9–10 times for A356), compared to CSC. Moreover, prolonging water spray delay time led to decrease in the cooling rate. Indeed, the AC has a more significant impact on reducing SDAS in A413 (60–75%) compared to A356 (45–61%). Moreover, decreasing the Si content in hypo-eutectic Al–Si binary systems limits the water spray delay time at a similar superheat. Besides, the reduction of eutectic silicon aspect ratio is nearly equal in both A413 (77–81%) and A356 (80–83%) alloys, through the AC compared to CSC. Furthermore, through the use of AC, the UTS of A413 and A356 increased by 112–130% and 78–100%, the YS of A413 and A356 increased by 8–21% and 31–42%, and the elongation of A413 and A356 increased by 333–620% and 110–252%, respectively, compared to CSC. These experimental results confirmed the simulation results. Finally, the transition of fracture from cleavage plane to dimple form occurred through AC for both A413 and A356 alloys, compared to CSC. In sound casting, it was found that the role of eutectic silicon in fracture was more prominent than Fe-containing intermetallic compounds. [ABSTRACT FROM AUTHOR]

This paper proposes a methodological framework to develop a data-driven process control using pure industrial production data from a cast iron foundry, despite the limitation of complete casting traceability. The aim is to help sand foundries to produce good castings. A reference foundry, which produces mainly automotive and oven parts with automatic sand molding and pouring machines, was selected. Past data, where only good castings were produced, were extracted from the database to determine parameter control limits (upper and lower control limits) with the aid of statistical approach. To identify critical process parameters associated with casting defects, process data from the zero and high scrap production batches were systematically compared. This method clearly identified unstable parameters without exact synchronization between inline and part quality data. Molding sand moisture, temperature and compactability, liquidus temperature of the melt, phosphorus content, carbon equivalent and pouring temperature were found to be the critical parameters to be stabilized. Finally, a regression model for predicting and controlling of molding sand moisture and liquidus temperature of the melt was created. The determined boundaries and the models were helpful for the foundry in assisting ongoing production control and correction of process inputs to achieve target casting quality. [ABSTRACT FROM AUTHOR]

The object of research in the paper is the production technology of casting «brake drum» from cast iron of the basic grade SCh20 according to GOST 1412-85 (DSTU EN 1561, EN-GJL-200). The existing problem is that due to the imperfection of the technological processes of manufacturing castings, final internal defects of a shrinking nature are possible. This can lead to a decrease in the strength and operational reliability of the drums, regardless of the chemical composition, which may meet the technical conditions and should provide the specified strength indicators according to the grade of cast iron. Based on the results of 3D modeling, it has been found that with the existing technology of manufacturing brake drum castings in one-time sand molds, final shrinkage defects are formed in the upper part of the casting. To eliminate this problem, a decision is proposed to increase the allowance for mechanical processing on the upper surface of the casting. The possible excess of the mass of the casting and excess consumption of the alloy that will occur when implementing this solution can be compensated by reducing the allowance on other surfaces based on their optimization by the method of dimensional chains and reducing the thickness of the casting wall. For this, a reduction in the carbon content in the alloy is proposed as a factor in increasing the tensile strength of cast iron. On the basis of 90 serial meltings in industrial conditions, the possibility of increasing the strength limit of cast iron by approximately 11 % by reducing the average carbon content in cast iron from 3.45 % to 3.4 % has been proven. The proposed solutions are the essence of improving the production technology of cast brake drums, which are produced by casting in one-time sand molds. The presented study will be useful for machine-building enterprises that have foundries in their structure, where iron is melted for the production of castings. [ABSTRACT FROM AUTHOR]

The complex sand-casting process combined with the interactions between process parameters makes it difficult to control the casting quality, resulting in a high scrap rate. A strategy based on a data-driven model was proposed to reduce casting defects and improve production efficiency, which includes the random forest (RF) classification model, the feature importance analysis, and the process parameters optimization with Monte Carlo simulation. The collected data includes four types of defects and corresponding process parameters were used to construct the RF model. Classification results show a recall rate above 90% for all categories. The Gini Index was used to assess the importance of the process parameters in the formation of various defects in the RF model. Finally, the classification model was applied to different production conditions for quality prediction. In the case of process parameters optimization for gas porosity defects, this model serves as an experimental process in the Monte Carlo method to estimate a better temperature distribution. The prediction model, when applied to the factory, greatly improved the efficiency of defect detection. Results show that the scrap rate decreased from 10.16% to 6.68%. [ABSTRACT FROM AUTHOR]

Developing novel filler sands has garnered significant interest in improving the ladle's free‐opening rate and enhancing the cleanliness of high‐Mn and high‐Al steel. Laboratory studies explore the effect of adding Cr2O3 powder on the sintering behavior of chromite‐based filler sands. Furthermore, interfacial phenomena are examined between the sands and the steel grades, varying in Mn contents. The results demonstrate that adding Cr2O3 power plays a role in inhibiting the liquid phase formation in the sand. With a 16% addition, the steel (Mn mass% = 30) reacts with the sand, leading to the shape of a spinel phase, specifically (Mn, Fe, Mg)O·(Al, Cr)2O3, which facilitates the separation of the liquid phase. The reduction of FeO to Fe by Mn, Al, and C in steel, especially Al, is hindered by adding Cr2O3, resulting in a suitable sintering degree that ultimately benefits ladle free‐opening. SiO2 is crucial for forming the liquid phase during the sintering process. The SiO2 content of the sand should be about 20% to achieve optimal sintering effects. Chromite sand for casting is not suitable for the steels. The mixed sand presented in the current study demonstrates potential as a suitable filler sand for the steel (20 ≤ Mn mass% ≤ 30). [ABSTRACT FROM AUTHOR]

For the manufacturing of sand cores, silicate inorganic binders have emerged as promising green casting binder materials; however, their adhesive performance requires further improvement. In this study, to evaluate the impact of using water-soluble polyols, i.e. polyethylene glycol (PEG) and xylitol, to modify silicate adhesives, the effect of the content and type of water-soluble polyol on the colloidal stability, wettability and adhesive performance of a silicate binder were investigated. The structural evolution of the modified silicate binder and the polysilicate bondswere studied using characterisation techniques including infrared spectroscopy and 29Si nuclear magnetic resonance (NMR) spectroscopy. Results revealed that PEG 400 and PEG 600 increased the size of polysilicate particles in the solution, resulting in flocculation of the silicate binders and easy precipitation or separation in a short period of time. However, PEG 200 and xylitol exerted little effect on the stability of the silicate solution. Moreover, 0.25 wt% PEG 200 reduced the surface tension of the solution from 78.93 to 54.15 mN/m and the equilibrium contact angle from 45.0° to 34.6°. The polyol promoted the dehydration and condensation of silicic acid gel to form a more stable three-dimensional network structure, improving the bonding strength of casting sand cores prepared using the silicate binder and silica sand from 2.42 to 3.02 MPa. This study not only unveils the role of PEG in improving the wettability and bonding behaviour but also provides an example of the rational use of environment-friendly water-soluble polyols to enhance the performance of green inorganic adhesive materials. [ABSTRACT FROM AUTHOR]

Laser Powder Directed Energy Deposition (LP-DED) is a promising Additive Manufacturing (AM) technology that offers the opportunity of repairing and revamping damaged or outdated parts and molds. Notwithstanding, it should be considered that the low surface quality of the produced parts makes post-processing operations necessary in order to meet the industrial requirements, and these operations strongly depend on the accuracy of the produced parts. In this paper, firstly an artifact for the LP-DED process, including classical features with and without curvatures, is proposed. Then, the dimensional accuracy and geometrical tolerances of the features are evaluated, limited to AISI 316L stainless steel. The findings of this work showed that the dimensional and geometrical tolerances of the LP-DED process are comparable with those of sand casting. On the other hand, tolerances are lower compared to Laser Beam Powder Bed Fusion (LB-PBF) technologies but are similar to those observed in Electron Beam Powder Bed Fusion (EB-PBF). • A 316L stainless steel artifact is designed. • The IT tolerance grade of the LP-DED process varies between IT15 and IT17, and lower IT value is obtained for larger basic size. • The IT tolerance grade strongly depends on the geometry of the feature. • Considering geometrical tolerances, surface profile error is about 1 mm, angularity error is about 0.3 deg. • And other geometrical tolerances are lower than 0.6 mm. • Higher errors are associated with larger geometries. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) printing is rapidly converging with the foundry industry in the recent years and tends to increase more in upcoming years. 3D printing is largely used for making sand molds and printing process uses sand which is imported. This sand in terms of costing is very high in comparison to Indian sand used in sand metal casting. Thus, waste generated from the printer is not affordable and increases the initial printing cost. To reuse the sand, reclamation is the solution which is effective and will reduce the initial printing cost. As the initial cost decreases printing process can be used for mass production of molds and cores. This paper presents a study of reclamation done on two types of waste sand printed and loose sand. It also suggests a range of temperature for reclamation of both the type of waste sand. Thermal process of reclamation is used as the binder used in the printing process is furan base. As furan binder evaporates at a certain temperature, the sand can be reclaimed and reused. [ABSTRACT FROM AUTHOR]

In this investigation, the influence of processing temperature on the formation, morphology, and dispersion of in situ TiB2 particles in AlSi5Cu3/TiB2 composites was studied. The AlSi5Cu3/TiB2 composites were developed at 750 °C, 800 °C, and 850 °C processing temperatures, keeping 60 min processing time, using sand casting. The rietveld analysis revealed that the content of TiB2 particles was 4.18%, 4.96%, and 4.31%, whereas the content of Al3Ti intermetallics was 0.40%, 0.00%, and 0.61% in the composites processed at 750 °C, 800 °C and 850 °C, respectively. Considering the highest number density (298) and least standard deviation (6), better homogeneous dispersion of particles was observed in 800 °C processed composites. With increasing processing temperature, the particle size was gradually increasing while the particle shape was not influenced. Due to the presence of more TiB2 particles, better homogeneous dispersion, and absence of undesirable intermetallics in 800 °C processed composite, hardness, tensile strength, compressive strength, impact strength, and flexural strength were improved compared to 750 °C and 850 °C processed composites. Moreover, TGA/DSC analysis, density, and specific strength were also evaluated. Overall, the results confirmed that the 800 °C processing temperature is optimal for the effective synthesis of in situ TiB2 particles. [ABSTRACT FROM AUTHOR]

The beneficial reuse of foundry dust discharged from sand casting process has good environmental and economic benefits. In this study, the alkali-activated foundry dust was used to prepare the non-sintered ceramsites, and the effects of modulus and content of sodium silicate solution on the compressive strength, water absorption rate, and softening coefficient of the non-sintered ceramistes were systematically investigated. The sodium silicate modulus and content ranging from 0.5 to 2.5 and 0 to 15%, respectively, were conducted. The microstructures and crystalline phases of the non-sintered ceramsites were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. The results demonstrate that sodium silicate with low modulus can remarkably improve the properties of the non-sintered ceramsites. The maximum compressive strength of the non-sintered ceramsites prepared by foundry dust can reach 4.05 ± 0.24 MPa, and the 24 h water absorption rate and softening coefficient are 6.61% and 0.75, respectively. The sodium silicate can stimulate the activity of foundry dust, promote the formation of (C, N)–A–S–H gels, and enhance the densification of the ceramsites, resulting in acceptable properties for the non-sintered ceramsites, which can be used in the construction industry. [ABSTRACT FROM AUTHOR]

In this paper, the adsorption behavior of KOH, LiOH and Na2HPO4 by sodium silicate was simulated by Materials Studio. Besides, the quantity of the complex modifier (KOH, LiOH and Na2HPO4) was optimized by orthogonal test, and the effect of complex modifier on the properties of heat-hardened sodium silicate-bonded sand (SSBS) was analyzed. This research was conducted with sodium silicate as a part of two-component binder system where the second part was silica fume to be used for heat-cured sodium silicate-bonded ceramic sand. The results showed that the optimum quantity was 3% KOH, 0.6% LiOH and 3% Na2HPO4. The instant strength, 4 h strength, 24 h strength and the 800°C residual strength of the modified SSBS increased by 66%, 37%, 56%, and 27%, respectively. The modifiers were stably adsorbed on the surface of the sodium silicate at 298 K. Herein, Na2HPO4 and sodium silicate formed a composite structure, which made the formed bonding bridge dense, thus improving the tensile strength of SSBS at room temperature. During the process of heating at 800 °C and air cooling to room temperature, due to the reduced adsorption of water, the collapsibility of SSBS was reduced. [ABSTRACT FROM AUTHOR]

The study focused on addressing casting defects in green sand casting that have negatively impacted the quality of the butterfly valve body. By employing various methods such as observation, interviews, numerical experimentation, and simulation, the researchers aimed to develop and evaluate a sand-casting technique for the butterfly valve body. Solidworks software was used to model the component and its gating system, while ProCAST software enabled mold filling and solidification analyses. The goal was to minimize shrinkage porosities in the cast butterfly valve body by optimizing process parameters through numerical experiments and the Taguchi technique. Analysis of variance (ANOVA) using Minitab 18 software analyzed the results. Through this research, the sand mold-related defect was reduced from 10% to 3%, and the special shrinkage defect was reduced from 26% to 2% by using a simulation of casting. [ABSTRACT FROM AUTHOR]

This paper addresses the flexible flow shop scheduling problem with unloading operations, which commonly occurs in modern manufacturing processes like sand casting. Although only a few related works have been proposed in the literature, the significance of this problem motivates the need for efficient algorithms and the exploration of new properties. One interesting property established is the symmetry of the problem, where scheduling from the first stage to the last or vice versa yields the same optimal solution. This property enhances solution quality. Considering the problem's theoretical complexity as strongly NP-Hard, approximate solutions are preferable, especially for medium and large-scale instances. To address this, a new two-phase heuristic is proposed, consisting of a constructive phase and an improvement phase. This heuristic builds upon an existing efficient heuristic for the parallel machine-scheduling problem and extends it to incorporate unloading times efficiently. The selection of the two-phase heuristic is justified by its ability to generate high-quality schedules at each stage. Moreover, new efficient lower bounds based on estimating minimum idle time in each stage are presented, utilizing the polynomial parallel machine-scheduling problem with flow time minimization in the previous stage. These lower bounds contribute to assessing the performance of the two-phase heuristic over the relative gap performance measure. Extensive experiments are conducted on benchmark test problems, demonstrating the effectiveness of the proposed algorithms. The results indicate an average computation time of 9.92 s and a mean relative gap of only 2.80% for several jobs up to 200 and several stages up to 10. [ABSTRACT FROM AUTHOR]

Traditional casting methods are losing their appeal due to poor working conditions. Integrating additive manufacturing into traditional Casting is a popular solution. Among the seven additive manufacturing categories, binder jet 3D printing is most suitable for 3D printing sand molds. However, issues like waste management and environmental problems in binder jetting need to be solved. The investigation proves that utilizing recycled sand as a raw material for 3D printing sand products can reduce the environmental impacts associated with binder jet 3D printing while achieving adequate mechanical properties. This study shows that recycled sand can produce mechanical properties comparable to new sand, while reducing waste and environmental impact. The study examines samples of new sand and recycled sand obtained from one to nine cycles of recycling. It reveals that the compressive and flexural strengths of sand recycled one to three times outperform new sand, while surface hardness remains unaffected by the recycling cycle. However, the permeability of the sand decreases as the number of recycling cycles increases. Recycled sand required less binder and hardener, which reduced costs and improved the environmental impact. This study highlights the importance of waste management and sustainability in 3D-printed sand mold processes and offers a promising solution for recycled sand powders in binder jetting. [ABSTRACT FROM AUTHOR]

Metal casting is one of the most widely used manufacturing methods, producing many of the goods used in everyday life. Recent innovations in additive manufacturing (AM) have allowed for more complex mold and rigging designs to produce higher-quality castings. One of the limiting factors preventing widespread adoption of these complex designs, however, is the inability to fully visualize and characterize the metal flow in these molds. This paper examines the use of open molds to evaluate liquid metal flow to better understand the flow characteristics that will ultimately influence casting performance. The study investigated two types of open molds along with two types of cameras to find the best method for evaluating the melt flow. The open molds used were direct 3D sand printed molds, and green sand molds made with AM patterns. The cameras used were a camera with a higher optical magnification but lower frame rate, and a camera with no optical magnification but a higher frame rate. The video from both cameras was processed using a video analysis algorithm to identify the melt head and calculate its change in position and velocity along the path of the runner. Additionally, the results from the experiments were compared against computational fluid dynamics (CFD) simulations, showing that CFD underpredicted the melt head velocity by 58%. Findings from this study can complement CFD models for evaluating mold design. Additionally, new training tools can be developed using this method to improve pouring control and consistency for foundries. [ABSTRACT FROM AUTHOR]

To promote the green and sustainable development of the foundry industry, it is necessary to further explore the new method, new technology, and new equipment for green foundry. In this paper, an innovative green casting method is proposed. The digital frozen sand casting technology uses water as the binder to replace the organic/inorganic binder for casting at low temperature, which solves the problems of difficult sand recovery and harmful gas emission during the casting process and realizes the high-performance green casting of complex castings. The green casting technology of digital frozen sand mold is a method to produce sand mold by freezing cutting and printing, and to obtain typical parts by mold assembling and pouring. In this paper, the basic theory, key technologies, and system equipment of frozen sand paving are systematically studied, and the application verification research is carried out on typical aluminum alloy parts. It reduced the amount of resin binder, improved the green level of casting industry, and provided a new green casting method for the casting field. [ABSTRACT FROM AUTHOR]

Direct part-markings (DPMs) can be formed into metal castings, using additively manufactured two-dimensional matrix encoded tags (AM2D) placed in a sand or shell mold. It has been unclear how thin a part can be and yet form a readable DPM. There must be sufficient molten metal to burn away the tag, and sufficient feeding pressure to form the 2D matrix code dot pattern. Here the formability limit for the casting of any AM2D (polymer) tag is shown to be the smallest heat energy from the latent heat of condensation needed to raise the temperature of the tag to ignition to burn the tag from the mold. The minimal part thickness that can be utilized is thereby derived. The minimum thickness is calculated to predict a part of various materials and compared positively with experiments. This provides a means to compute required part metal thickness to positively form a DPM tag before casting. [ABSTRACT FROM AUTHOR]

The drive to lower the carbon footprint of the automotive industry has led to the development of high efficiency diesel engines. The materials used for diesel engine components must withstand greater thermomechanical loading, as compared to gasoline engines. Thus, to determine the feasibility of using conventional aluminum-based powertrain alloys for next generation high efficiency engines, the present study evaluates the elevated temperature (250 and 300 °C) tensile and creep performance of a T7 319-type alloy. To represent real-world conditions, the 319 samples used in this study were extracted from the cylinder bridges of a sand cast engine block and then conditioned at their respective test temperatures for 200 hours. The results indicate that at 250 °C (~30–50 °C above current engine operating temperatures), the tensile strength and creep resistance of the T7 319 alloy will be able to withstand current cylinder pressures (i.e., 22 MPa) and may allow for an increase up to 30–35 MPa. However, at 300 °C, the strength decreases by more than 50% and tertiary creep initiates at 40 MPa. As such, the inherent evolution of residual stress during current engine block manufacturing technologies prevents the safe use of the 319 alloy in engine applications operating at 300 °C. [ABSTRACT FROM AUTHOR]

The simulation of the sand gravity casting process is complicated due to its multiscale and multiphysics nature. Although there are many commercial software options available, it remains extremely difficult to accurately predict the filling, solidification, and defects such as oxidation. Smoothed particle hydrodynamics (SPH) is a Lagrangian simulation approach that is particularly well-suited for modeling the gravity casting process. To validate the results of the filling, cooling, and solidification steps of the SPH method, it is interesting to introduce and design a 3D universal experimental test case of the gravity casting process that can be modeled in 2D. This universal test case is developed so that the hydrodynamic filling process can be analyzed in 2D while the cooling and solidification processes can be investigated in 1D. After comparing ProCAST, a commercial 3D mesh-based software, with the 2D SPH method, the results highlight the unique advantages of each approach in analyzing filling step and temperature evolution. The SPH simulations are better at capturing the essential aspects of fluid motion. [ABSTRACT FROM AUTHOR]

The effect of additions of alloying elements (Mo and Ni), austempering time and thickness of the product section on the mechanical properties of industrial ductile iron of grade GGG-70 (EN-GJS-700-2) is studied. Standard keel blocks and crankshafts have been produced by static sand casting from unalloyed, alloyed with 0.2% Mo and 0.2% Mo + 0.6% Ni ductile iron. Austempering is carried out at 350 °C for 90, 120, 150, and 180 min in a salt bath. It is shown that the alloying has a significant effect on the ability of cast iron to austempering and its mechanical properties after heat treatment. Alloyed cast iron has the best combination of ultrahigh yield and tensile strength with high ductility. After austempering, crankshafts alloyed with 0.2% Mo + 0.6% Ni have a typical ductile iron ADI structure even in the thickest sections (58-mm-thick main bearing center) with a uniform hardness distribution. [ABSTRACT FROM AUTHOR]

Acquiring small-scale experimental techniques that allow analysis of casting defect in large-scale ingot is beneficial to understanding its phenomena. In this study, we report an experimental technique using sand mold to analyze (reproduce and evaluate) casting defect that occur in large-scale ingot. We cast carbon steel (500 kg) by top pouring into a sand mold in which a chill plate (SS400) was installed to enhance cooling of a part of the mold, and observed structure and segregation. Equiaxed crystals were formed in the lower part of the ingot, and negative segregation of carbon was formed in the region of the equiaxed crystals. Al2O3 inclusions were present in the region of negative segregation. This meant that solid movement was generated during the solidification process. Additionally, porosities and shrinkage were also formed in the ingots. This experimental technique using sand mold is expected to be used as an experimental technique that can analyze casting defect that occur in large-scale ingot. [ABSTRACT FROM AUTHOR]

To improve the casting quality as well as the casting efficiency during the casting process, the effect of the interaction of process parameters and system structural parameters on the shrinkage volume and efficiency of the casting was investigated in this paper by using the response surface method for the simulation prediction of A356 alloy sand casting. The relationship between variables and response (shrinkage volume, solidification time) was established by Box-Behnken Design with pouring temperature (650–710 °C), mold preheating temperature (200–300 °C), width/thickness ratio of cross-section of sprue (1.2–1.5), width/thickness ratio of inner sprue section (2–4) and length/diameter ratio of straight sprue (1.5–2.5) as variables by the response surface method. The results are then optimized, and the optimal solution is selected by the NSGA-II algorithm and TOPSIS method. The results show that the changes in the cavities of the optimized and improved pouring system enhance the flow of the metal fluid and make the filling more complete. The gentle cooling of temperature is conducive to heat dissipation and layer-by-layer sequential solidification, which can effectively eliminate the casting's internal shrinkage loosening and shrinkage holes defects, thus forming a dense casting with good performance. After solving the optimized parameters and improving the pouring system, the solidification time (integrated solidification time) was reduced from 129.24 to 88.10s, and the shrinkage volume was reduced from 9.68 to 4.06 cm3. [ABSTRACT FROM AUTHOR]

This study aims at investigating the possibility of rolling and increasing both the tensile strength and the elongation of thin-wall non-alloy ductile cast iron with a composition of C = 3%, Si = 4.15%, Mg = 0.04%, Mn = 0.36%, and carbon equivalent (CE) of 4.39% through the improvement of microstructure using ablation casting compared to conventional sand casting. A barium containing post-inoculant (Si = 72–77%, Ba = 2.0–3.0%, Ca = 1.0–2.0%, Al = 0.8–1.5%, Fe = bal.) was employed as inoculant to produce thin-wall ductile cast iron castings. Specimens with initial thicknesses of 4.4 and 8.3 mm were hot rolled at 780 °C and 900 °C for ablation and conventional method, respectively. The rolling process on the specimens improved the mechanical properties significantly. The microstructure of the ablation specimens after rolling consisted of elongated graphite, ferrite encapsulating graphite, bainite and martensite, while the microstructure of the normal specimen after rolling consisted of elongated graphite, carbide, and martensite. The ablation specimens with thicknesses of 4.4 and 8.3 mm were subjected to strains of 58% and 78%, respectively, and the ultimate tensile strength values obtained were 1257 and 873 MPa, respectively. Conventional specimens were also subjected to strains of 34% and 58%, and the ultimate tensile strength values obtained were 948 and 745 MPa, respectively. Moreover, the highest elongation (16.3%) was reported for the 8.3-mm-thick specimen. The results show that rolling on thin-wall ductile cast iron castings improved the microstructure and increased the tensile properties of cast iron components. [ABSTRACT FROM AUTHOR]

The Indian foundry industries are facing problems to produce the casting at a lower cost due to an increase in the cost of the raw materials. On the other hand, the use of Fe–Cr slag as a mold material in foundry industries was not explored. Therefore, the present investigation was focused on the designing and optimization of Fe–Cr slag mold's constituents for Al-alloy (A356) castings. The optimum properties of the Fe–Cr mold such as mold hardness number, permeability number, compressive, and shear strength were found to be 87, 158, 1.45 kg/cm2, and 0.38 kg/cm2, respectively. Aluminum alloy (A356) castings were made from Fe–Cr slag and silica sand mold. It was observed that Fe–Cr slag mold casting has good dimensional stability in comparison to silica sand mold casting. The Brinell hardness and microstructure of the castings were evaluated and a possible structure-property relationship was explained. It was observed that Fe–Cr slag has a lot of potentials to be used as an alternative to silica sand mold for Al-alloy castings. However, its recyclability, production of required particle size of Fe–Cr slag using atomization, and its cost need to be studied before recommending its use in Indian foundry industries. [ABSTRACT FROM AUTHOR]