Sand Casting Research Articles

Dual-Alloy Sand Mold Casting: Main Principles and Features

AbstractThe multi-material injector casting (MMIC) process allows the production of castings with two different alloys in a single process. The metal is introduced into the mold through a ceramic down sprue (injector) that moves with the rising surface of the melt. This results in a beneficial temperature distribution in the casting with enhanced filling and feeding properties. Combining two alloys in one casting affects the chemical composition, microstructure, and mechanical properties, which differ from those of the original alloys. The main goal of producing the dual-alloy castings is to adapt the alloy locally in the mixing zone according to the application needs. The original composition and characteristics of both alloys have to be ensured as much as possible. This article discusses the peculiarities of dual-alloy sand mold casting, considering the oxidation processes of the components under different conditions and the microstructure of the resulting ingots. The results of thermodynamic simulation, experimental dual-alloy sand mold casting, chemical composition, and macrostructure of the resulting castings are given in the article. The following factors have been investigated: the method of pouring two alloys (AlSi12 and AlSi9Cu3), which simulate two injector positions; the time between pouring each alloy (60, 90, and 120 s); the influence of a directional solidification with the bottom chill. The mixing zone was identified by the changes in the content of Cu measured by spark spectroscopy and EDS.

Determination of interfacial heat transfer coefficient at the frozen sand mold casting process of ZL101 alloy

Compared to the resin sand mold casting process, frozen casting is more environmentally friendly, providing a better working environment and enhanced supercooling degree. The interfacial heat transfer coefficient (IHTC) between frozen sand mold and metal is an important parameter that significantly influences the final mechanical properties and microstructure of the castings. This paper solved the inverse heat conduction problem using the finite difference method (FDM). In addition, the conjugate gradient method (CGM) was adopted to calculate the temperature distribution and heat flux in the molten metal. At the same time, the particle swarm optimization algorithm (PSO) was used in temperature distribution determination in frozen sand mold. The interfacial heat transfer coefficient (IHTC) was estimated during the solidification of ZL101. The results showed a good agreement between calculated and experimental data, obtaining accurate casting interface temperature Tm, frozen sand mold interface temperature Ts, heat flux q, and IHTC. The analysis of the IHTC variation revealed a water content value within the range of 4 wt.% to 5 wt.% resulted in IHTC in two types of interpretation, called ‘fluctuation type’ and ‘turning type’.

The Use of 3D Printed Sand Molds and Cores in the Castings Production

As a part of this work, an analysis of the current state of knowledge regarding the use of additive technology - binder jetting in the production of castings was made. The binder jetting (so-called 3D printing) has become the leading method of sand mold and core production. Within this paper types of molding and core sands with organic and inorganic binders that are and can be used in technology were analyzed. The need to carry out works aimed at developing pro-ecological molding / core sands with inorganic binders and organic binders with reduced harmfulness to the environment dedicated to binder jetting technology was noticed. The influence of technology parameters on the properties of molding / core sands and the properties of cast components was analyzed. It was shown that thanks to the unlimited shapes of the systems obtained with the use of additive technologies, it is possible to influence the rate of heat dissipation through the mold, which positively effects the process of solidification and crystallization of the castings.

On the mechanism of binder migration in furan binder jetting of sand molds and cores

Binder Jetting is a layer-based additive manufacturing process in which a printhead deposits droplets onto a pre-prepared layer of particles. Upon droplet impact, the binder begins to migrate and infiltrate adjacent areas away from its originally intended location. The purpose of this study is to investigate the mechanism of furan binder migration. Observing in-situ binder spreading is challenging, especially for the furan binder used in this work. The strong discoloration of the surrounding sand makes it difficult to distinguish between the printed pattern and the surrounding loose sand. For this reason, a fluorescent dye is added to the binder. A wavelength-matched laser in the binder jetting machine provides the excitation energy, and in-situ observation of binder migration becomes feasible. The results show an unexpected behavior where the actual microscopic fluid redistribution of the binder does not match the observed macroscopic measurements of other reports. It becomes clear that the migration mechanism of furan binder in sand binder jetting is strongly influenced by gaseous mass transport. To support this theory, a phenomenon called boundary zone is studied by micrographic and computed tomographic analysis. This outer shell region surrounds samples with higher binder contents and extends over a thickness of approximately 400 µm. The binder content here is significantly higher than that of the core of the specimen and its target value, demonstrating that liquid concentration equalization is not feasible. A plausible explanation is evaporation and condensation of binder, resulting in localized binder accumulation in areas of high catalyst to binder ratios. Since binder evaporation is an overlooked issue in furan binder jetting, additional experiments are performed to demonstrate the extent of evaporation. For this, particle layers are deposited on a scale, the printhead deposits binder, and the resulting mass loss is recorded. With a better understanding of binder migration, new strategies can be developed to reduce geometric deviation, improve geometric precision, and possibly allow for higher layer thicknesses in furan sand binder jetting.

An Investigation of the Thermal Properties of LM13- Quartz- Fly-Ash Hybrid Composites

In the present work, a metal–matrix composite was casted using the LM13 aluminum alloy, which is most widely used for casting automotive components. Such applications require materials to withstand high operating temperatures and perform reliably without compromising their properties. In this regard, particulate-reinforced composites have gained widespread adaptability. The particulate reinforcements used comprise of one of the widely available industrial by-products. which is fly ash, along with the abundantly available quartz. Hybrid composites are fabricated through the economical liquid route that is widely used in mass production. Though there are numerous published research articles investigating the mechanical properties of metal–matrix composites, very few investigated the thermal properties of the composites. In the present work, thermal properties such as thermal conductivity and thermal diffusivity of cast hybrid composites were evaluated. The particulate reinforcements were added in varied weight percentages to the molten LM13 alloy and were dispersed uniformly using a power-driven stirrer. The melt with the dispersed particulate reinforcements was then poured into a thoroughly dried sand mold, and the melt was allowed to solidify. The quality of the castings was ascertained through density evaluation followed by a microstructural examination. It was found that the composites with only the fly ash particles as a reinforcement were less dense in comparison to the composites cast with the quartz particulate reinforcement. However, the hybrid composite, with both particulate reinforcements were dense. The microstructure revealed a refined grain structure. The thermal diffusivity and thermal conductivity values were lower for the composites cast with only the fly ash reinforcement. On the other hand, the composites cast with only quartz as the particulate reinforcement exhibited higher thermal diffusivity and thermal conductivity. The specific heat capacity was found to be lower for the fly ash-reinforced composites and higher for the quartz-reinforced composites in comparison to the LM13 base matrix alloy. However, the highest value of thermal diffusivity and thermal conductivity were reported for the hybrid composites with a 10 wt.% inclusion of both fly ash and quartz particulate reinforcements.

Data-driven casting defect prediction model for sand casting based on random forest classification algorithm

Data-driven casting defect prediction model for sand casting based on random forest classification algorithm

Study on the Mechanical Properties of 3D-Printed Sand Mold Specimens with Complex Hollow Structures.

Casting, as a fundamental process in metal forming, finds widespread applications in the manufacturing industry. The advent of 3D printing hollow sand mold technology presents a novel method for casting technology to revolutionize traditional dense sand molds, offering increased flexibility in achieving quality control and improvement in casting processes. Consequently, this study delves into an examination of the mechanical strengths of 3D-printed sand molds with complex hollow structures and further investigates the influence of hollow sand mold concession on castings. The results indicate that compressive and high-temperature residual tensile and bending strengths vary in hollow structures. Multi-layer shells have greater high-temperature residual tensile, compressive, and bending strengths than truss hollow sand molds with roughly the same hollow volume fraction. Compared to dense sand molds, hollow sand molds, which have a lower mechanical strength, have better retractability, which helps reduce the residual stress and crack tendency of castings. The breaking of hollow structures is limited to local areas, unlike the penetrative cracking of dense sand molds. The I-beam-shaped casting test results indicate that a hollow structure is beneficial for the preservation of the integrity of a sand mold during the casting process. Compared to dense and truss hollow molds, a multi-layer shell hollow sand structure has the comprehensive advantages that it improves retractability while maintaining strength relatively well, reduces the residual stress, and avoids cracks in castings and itself.

Comparative Studies of Microstructural, Mechanical and Tribological behaviour of A319 alloy cast in solid waste mold and conventional sand Mold

Abstract This study investigates the potential of utilizing industrial solid waste (blast furnace slag, ferrochrome slag, and red mud) as mold materials to improve the solidification rate and wear resistance of A319 alloy. Unlike conventional molds such as silica sand and olivine sand, industrial solid waste poses an eco-friendly alternative, contributing to waste valorization. The motivation for this research drives the need for sustainable and efficient waste management practices in the industrial sector. By exploring the utilization of industrial solid waste as a mold material, study aims to address the current challenges in disposal, reduce environmental impact, and enhance the overall performance of A319 alloy through improved solidification and wear resistance. The experimental phase involved multi-factor reciprocating sliding wear tests conducted on a sample using a linear reciprocating tribometer, employing a steel ball as a counter face. The investigation of reciprocating wear characteristics aimed to assess the correlations between solidification rate and wear properties of a specimen cast in an industrial solid waste mold as well as a sand mold. Notably, tribological test results revealed a low wear rate of 3.3 mg/Km for the blast furnace slag mold. The scanning electron microscopy (SEM) image of the wear surface showed adhesive wear mechanisms. This study contributes valuable insights into the potential environmental and performance advantages of repurposing industrial solid waste for foundry applications.

“Experimental Assessment Of Microstructure And Corrosion Properties Of Sg Iron (400/15 Grade) Under As-Cast And Nitrotec Treated Condition”

Spheroidal Graphite (SG) iron castings (conforming to IS 400/15 grade) are made in green sand moulds. Test specimens are then machined from the castings. One set of Specimens is then subjected to Nitrotec Treatment, treating the surface with nitrogen atmosphere which resulted in the formation of Fe3N layer. The Nitrotec temperature selected is 5700C and 6300C. Specimen is held at this temperature for a fixed duration of 180 minutes and then quenched in quench bath (water based quenchant) maintained at 500C. The effect of Nitrotec Treatment on microstructure and corrosion is studied and compared with as-cast ones. The results of the research indicate the Graphite nodules are more or less uniform and distributed evenly in the ferritic matrix. The nodules count shows an average of 90 nodules/mm2. Corrosion or rusting is essentially a process of oxidation in which iron combines with water and oxygen to form rust, the reddish-brown crust that forms on the surface of the iron. Nitrotec treated specimen treated at 570º C exhibit lower corrosion rate compared with the ones treated at 630º C. This may be due to the higher hardness values obtained for low Nitrotec temperature treated ones. From the above investigation it is clear that the Nitrotec treatment has an effect on the microstructure and corrosion properties of SG iron castings leading to further investigation on Nitrotec treated SG iron by changing different parameters.

Effect of Matrix Type on Properties of Moulding Sand with Barley Malt

The aim of the following work was to determine the possibility of using barley malt as a binder in moulding sands technology. The moulding sands prepared on the basis of three kinds of sands, i.e. quartz, olivine and chromite sands were analyzed. In order to determine the properties of moulding sands, typical determinations were made, i.e. moisture content, flowability, permeability, strength properties and abrasion wear. The obtained results indicate that it is possible to use barley malt as an independent binder for masses made of quartz, olivine and chromite sands.

Analysis of Influence of Sand Matrix on Properties of Moulding Compounds Made with Furan Resin Intended for 3D Printing

Binder jetting (BJ) sand printing is a 3D printing process in which a sand mould or sand core is produced from an STL file. A single layer of a sand matrix consisting of one or more grains in height of sand is applied to a worktable, and then a liquid resin or binder is applied to bond the grains together. This process is repeated until the final result matches the CAD model. The sand matrix is the main component of ceramic cores and moulds. The present study aims to demonstrate the influence of the matrix used on the properties of the resulting moulding sand. Three types of sand matrices were selected for the study. The first was a quartz matrix for 3D printing with binder jetting; this is characterised by a sharp geometry that allows for proper layering during printing. Ordinary quartz sand was also used for the study; this type of sand is usually used for the production of sand cores in the hotbox process, among other things. The shape of this sand is irregular. The last matrix to be tested was Cerabeads sand; this was selected because its spherical geometry clearly distinguishes it from the other two matrices. The matrices were analysed for their grain sizes. Scanning electron microscope images were also taken to compare the geometries and chemical compositions of the respective matrices. In presented research utilises a sand matrix for the production of self-curing compounds with furan resin dedicated for binder jetting 3D printing. The moulding masses were produced in a laboratory circulation mixer. The laboratory moulds were produced with wooden core boxes and pre-compacted by vibration. The samples from the matrix for the 3D printing were produced using the binder jetting method. The samples were produced to determine the flexural strength, tensile strength, gas permeability, hot distortion, and apparent density. It was not possible to carry out tests for the Cerabeads sand, as the obtained moulds were too brittle to perform adequate tests. Tests with the other matrices have shown that the shape and size of the matrix affect the apparent density and gas permeability.

Application of sand mold casting modelling for casting pump volute

This work details the development of a gating system for sand mold casting utilizing advanced computer technologies in the casting industry. The study employs advanced methods to manufacture a component referred to as the pump volute. Made from the EN-GJN-HV600(XCr23) alloy, this component displays superior technological characteristics, notably for the production of sand mold gravity castings. SolidWorks software is utilized to generate 3D models of the component and the fill system based on predetermined dimensions. Subsequently, the component is imported into Pro-CAST software to conduct a simulation. Various time parameters were inputted during the study. Post-simulation, defects were scrutinized, and the casting system underwent modification to eliminate them. The process was iterated on the software and its efficacy was verified to be faultless.

Safety assessment of sand casting explosion accidents by testing cavity pressure of the sand mold to protect employee health

Excessive cavity pressure may result in a sand casting explosion, and corresponding measures should be adopted to prevent these consequences. In this study, the pressure variations in the cavity were first investigated based upon on-site testing by taking the resin contents into consideration, and then the evolution characteristics of sand casting explosion accidents were analyzed in depth by system dynamics, chaos theory, and the bow-tie model. When the resin contents are 1.3 wt%, 1.4 wt%, and 1.5 wt%, the pressures of the gas vent increase by 27.0 Pa, 32.8 Pa, and 35.6 Pa, respectively. To reduce the pressure of the cavity, the resin content should be reduced. The evolutionary process of sand casting explosion accidents has a noticeable butterfly effect and randomness, whose occurrence is comprehensively affected by human, object, environment, management and emergency subsystems. The leading causes of sand casting explosion accidents mainly include the extensive gas evolution characteristics of foundry sand, cavity exhaust blockage, and inadequate safety monitoring. The leading consequences of sand casting explosion accidents mainly include casualties, secondary disasters, and social panic. The implications of these findings concerning sand casting explosion accidents can be regarded as the foundation for accident prevention in practice.

Optimization and empirical studies of riser design in sand casting process using different mould properties

Optimization and empirical studies of riser design in sand casting process using different mould properties

Numerical simulation of the bentonite-bonded sand mould compaction process using micro-mechanical parameter relationships

ABSTRACT Commercial software packages for FEM analysis have been used to numerically simulate the behaviour of the complex systems of bentonite-bonded sand mould under pressure and subjected to stress distributions and to predict their performance. The Drucker-Prager model and the Mohr-Coulomb model are two well-known mathematical models used to describe the plastic non-linear behaviour of the soil. Conducting direct shear tests on varying densities of sand can provide the individual parameters necessary for the simulation of the moulding process. A new approach is based on making relationships between micro-mechanical parameters and changes in sand density during the compaction process. COMSOL Multiphysics is a popular software tool used to implement FEM simulations. The steps involved drawing geometry, inserting material properties, mesh generation and time-dependent density, and solving the model. The boundary conditions depend on the particular problem being analysed, which defines the external forces and constraints acting on the structure. The use of a coarse mesh and stationary study may be a computationally efficient approach for the evaluation of the compaction process of green sand. The study found that the maximum displacement value is 6.1*10−3 mm, the maximum volumetric strain value is 8.88*10−5, and the von Mises stress is 4.14*103 N/m2.

Preliminary Study on the Potential of Krueng Mane River Sand for Metal Casting Use

Sand casting is a metal casting process to make a component by pouring molten metal into the sand mold. The casting process, the sand is the fundamental material used for mold making. The sand used is generally silica sand, river sand, mountain sand, and beach sand. The sand for molding must have requirements such as having formability, suitable permeability, good distribution of sand grain size, resistance to high temperatures, suitable binder composition, and sand must be cheap. This study investigated to determine the potential of Krueng Mane river sand in Aceh Indonesia for its possible use for metal casting. The important properties studied are moisture content, total clay content, grain fineness number, and grain shape. Tests are carried out following the standards and procedures defined by the American Foundrymen’s Society (AFS). Results obtained revealed that the river sand has average moisture content of 7.78 %, clay content of 3.20%, and grain fineness number (GFN) of 46. Krueng Mane river sand will be suitable for casting of casting of light steel, heavy grey steel, medium grey iron, and non-ferrous metals, with the addition of binding agent in suitable proportion.

Study of Moulding Sands to Create Three-Layer Magnesium Concrete

Abstract The article is devoted to the problem of creating energy-efficient building materials for enclosing structures. The aim of the research is to develop a recipe and a method for moulding sands placing to create heat-insulating concrete of a multilayer structure. The three-layer magnesium concrete containing layers of different densities is an object of a scientific research. Compositions of moulding sands for concrete’s central and surface layers have been developed and studied. Materials specially developed were used as raw materials for moulding sands; they are as follows: composite magnesial binder and porous filler obtained by low-temperature firing of a granular mixture based on sodium liquid glass and thermal energy waste (fly ash from thermal power plants, aluminosilicate microsphere). Possibility of regulating moulding sand’s properties for concrete’s central layer by varying the content and fractional composition of porous granules has been shown. There has been proposed the moulding sand for surface layers of three-layer magnesium concrete containing crushed porous sand. The related composition of moulding sands favours with adhesion of concrete’s different layers. Various technological methods for producing magnesium concrete of a complex structure have been studied. The research reveals technological and operational characteristics of three-layer magnesium concrete obtained by horizontal and vertical deposition of moulding sands.

EFFECT OF CHILLS ON SAND CASTING OF ALUMINIUM ALLOY

This study investigated the effect of chill in the sand casting of aluminum alloy. Eight cylindrical rods of dimension 7.5mm × 40mm and a four-disc shape sample were cast using a sand mould. Alumina Oxide, Iron filling, and Zinc chills were stirred into the melt of three sand molds and the last sample was left unchilled. The investigation involved testing of mechanical properties and metallographic analysis of cast samples. The results revealed that the sample chilled with zinc has the highest mechanical properties but the lowest wear resistance (Tensile strength of 155.23312MPa, hardness of 50.24559BHN). Also, the sample chilled with alumina oxide revealed an evenly distributed microstructure due to its unique properties and its highest wear resistance. The iron filling chill sample displayed very close mechanical properties with the sample without chill (Tensile strength of 133.56225MPa, hardness of 43.18315BHN) (Tensile strength 133.85680Mpa, hardness of 42.94031BHN).

Effects of hollow sand mold on the microstructure and mechanical properties of a low pressure aluminum alloy casting

The hollow mold revolutionizes conventional dense mold design as it can optimize the solidification and cooling processes of casting and offer potential to improve performance of castings. In this paper, the effect of hollow mold structures on the microstructure and mechanical properties of a low pressure thin-walled aluminum alloy conical cabin casting was investigated. A hollow mold combined by four sectors with different shell thicknesses was tactfully designed. The hollow mold structures delayed the cooling and solidification of casting. They significantly reduced the pore defect from 0.4 % to 0.03 % at the lower, from 0.68 % to 0.04 % at the middle and from 0.3 % to 0.03 % at the top, compared to dense mold. In the lower and middle areas of casting, improvements of 1.0 % and 1.1 % in mechanical properties were respectively achieved when applying 50 mm-thick-shell hollow sand molds compared with using dense sand mold, while an improvement of 1.1 % was achieved in the upper area of casting with 70 mm-thick-shell. This allows designers to create hollow molds with different shell thicknesses depending on the position in the casting to meet specific needs. For example, thin shell for the bottom to achieve high fluid flow and feeding while thick shell for the top for improved cooling. For castings with wall thickness of 10 mm–20 mm, the most effective shell thickness for the hollow mold is 50 mm–70 mm. The hollow mold provides the feasibility to differentiated semi-quantitatively control the solidification and cooling processes of castings, which can be applied in production of high-end castings in the future.

Effects of Die Entry Angle on the Mechanical Properties of Extruded Lead Alloy

The use of lead to produce wire, power cable sheathing, guide plates, and other wide-range applications require fine-grain structures. Researchers adopted severe plastic deformation, as a means of attaining ultra-fine grain structure. However, this technique is rather expensive and time-consuming. Thus, this study is focused on the application of a simple extrusion technique to achieve fine grain structure in the lead alloy by using different die entry angles to study the microstructural and mechanical properties of lead alloy. Lead alloy samples were cast into cylindrical billets in a sand mould, machined, and tapered at the edge to ease entry into the die for the extrusion process. The die tools were made of mild steel with die entry angles of 15°, 30°, 45°, 60°, 75°, and 90°. Subsequently, the extrusion was performed with the aid of a hydraulic press machine that provided pressure on a cylindrical punch and forced the billet through the extrusion die. The mechanical and microstructural properties were studied, using the micro-hardness tester and metallurgical microscope, respectively. The results show that the maximum extrusion stress of 70 MPa of lead alloy occurred at a die entry angle of 45°, which is three times that of the conventional alloy (18 MPa) with crystal clustering and fine microstructure. The ductility of lead alloy improved when processed at a 60° die entry angle with extrusion stress of 63.3 MPa, with no significant increase in hardness with die entry angles (7.7-9.0 HV). The grains show an appreciable reduction in size and enhanced surface finish