Precision Casting Research Articles

Rapid prototyping of wax models for investment casting

This article discusses making wax models for precision casting technology. Our chosen method of making these prototypes consists in printing the positive of the model on 3D printer, which is then molded into rubber. The resulting rubber mold is used for casting the wax models. The focus of the article is mainly on the quality, speed, and accuracy of making wax models, while they will be compared with commonly produced wax models.

The Influence of High-Temperature Helium and the Amount of Revert Material on the Material Properties of Inconel 738

Nickel-based alloys are considered promising materials for primary circuits of high-temperature gas reactors (HTGRs), specifically for gas turbines. The primary helium (He) coolant in the gas-turbine-based HTGRs is expected to reach temperatures of up to 900 °C; therefore, the selected materials should adequately perform over a long service life at such an environment. A promising manufacturing method in the production of reactor components is precision casting, where the content of revert (recyclate) material in the alloy differs and can influence the material behavior. In our study, Inconel alloy 738 was manufactured by casting 50% and 100% of revert material and tested in HTGR conditions to examine the influence of helium coolant on the material’s properties. Tensile specimens were exposed at 900 °C for 1000 h in helium containing a specified amount of gaseous impurities. Scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), in combination with X-ray diffraction (XRD) and nano-, microhardness methods, were used for material characterization after performing the tensile tests at room temperature. The presence of three types of layers was observed: a thin layer formed by aluminum and chromium oxides on the surface; non-uniform surface oxides Ti3O5 with inner (Al,Cr)2O3; and the inner fine-grained Inconel Cr-enriched phase (approx. 10–20 µm below the surface), which can act as a protective surface layer. Mechanical properties of both revert materials decreased after exposure to HTGR conditions but did not show a significant difference as a result of the content of the revert material. The increase of nano-hardness in line profiles throughout the specimen’s cross-section was observed locally at the surface oxides and in the precipitates and grain boundaries. After exposure, Rp0.2 values decreased by 20% and 17.7%, and Rm values by 12.3% and 20.8% in samples with 50 and 100% revert content, respectively. Furthermore, a decrease in microhardness values (HV0.1) was detected by 4.98% in longitude and 5.80% in cross-section for samples with 50% revert material and by 3.85% in longitude and 7.86% in cross-section for samples with 100% revert material. It can be concluded that both revert materials have similar corrosion resistance in HTGR conditions. The presented results complement the knowledge about the degradation of alloys in the coolant environment of advanced gas-cooled reactors.

Manufacture of thin-walled steel castings via consumable additive patterns

The problems of thin-walled steel casting are usually connected with insufficient level of alloy fluidity in the field of operating casting temperatures, as well as with appearing counter-pressure for the alloy which fills the narrow mould sections. These sections correspond to thin walls of the future casting, depending on restricted gas permeability of a mould. To solve these problems, the methods of precise casting via thermodeleting patterns, as well as the methods of external effect on metallic melt which fills the mould. This work analyzes the accumulated experience of casting via lost and consumable patterns, the features of their practical realization in the conditions of a casting mould vacuum treatment; their disadvantages are shown as well. The authors formulated the task to eliminate the revealed disadvantages, to provide stability of the technological process and high quality of manufactured castings (in particular for surface defects, non-metallic inclusions, violations of geometrical shape and dimension accuracy) together with lowering of labour intensity and energy intensity of casting in comparison with Replicast–CS-process as a prototype. The innovative technology of casting via consumable patterns was suggested and successfully tested in the conditions of operating production facilities. This technology differs from the prototype in such way, that the patterns are fabricated via additive technologies providing obtaining of internal cellular adjustable structure from the material which is burnt at the temperature not more than the lower temperature threshold of polymorphic transformations of a filling agent of refractory suspension. This refractory suspension is applied on the pattern block with 1-2 layers, sintering of ceramic shell and burning of a pattern block are carried out after placing the pattern block in a moulding box and its filling by fluid self-hardening mixture. Then mould filling by metallic melt is conducted after solidification and restoration of the required gas permeability of fluid self-hardening mixture, while vacuum treatment of the mould is stopped after reaching the solidus temperature by metal. The authors believe that the suggested technology can be used for manufacture of castings of special duty from low-carbon steels and other alloys, which are sensitive to destruction of consumable patterns manufactured via additive technologies (additive patterns).The research was carried out at the expenses of subvention within the framework of Kazan(Privolzhskiy) Federal University in order to rise its competitiveness among the leading global scientific and education centers.

Thermomechanical fatigue of round tube specimens manufactured by precision directional solidification casting method

AbstractIn the present study, a superalloy round tube specimen prepared by directional precision casting without mechanical turning is experimentally investigated under the thermomechanical fatigue conditions of the in‐phase and out‐of‐phase thermomechanical angels from 500°C to 1000°C. The deformation behavior and damage mechanism of the round tube specimens under TMF load are discussed. It was confirmed that the tension–compression asymmetry under TMF cycling is affected by temperature–load phasing and mechanical strain range. Moreover, the damage to round tube specimens includes creep, fatigue and oxidation. Due to the concentrated stress, the rough surface of the specimen provides suitable locations for crack initiation. A novel life prediction approach that combines the Neu–Sehitoglu model and modified Manson–Coffin model was proposed in response to the traditional life model's insufficient prediction performance. This method may explain the TMF life of precision cast specimens.

Lithography-based additive manufacturing of porosity graded alumina

• In recent years, alumina ceramics exhibiting gradient in porosity, i.e., porosity graded alumina ceramics (PGACs), with a controlled amount of both open/closed or macro/micro pores is of high interest for several applications such as thick barrier coating, cores for precision casting, biocompatible implants, membranes/filters, and fabrication of functionally graded metals through infiltration. • Lithography-based Ceramic Manufacturing (LCM) offers high quality and near-net manufacturing of complex ceramic components with high resolution. • Two-vat system in the newly developed multi-material LCM printer setup enables not only assigning one material to any desired layer but also use of different materials in each layer by assigning the respective materials to selected pixels of the layer image. • This article introduces methodologies for the fabrication of porosity gradient alumina with continuous and discrete porosity transitions zones by combining sacrificial templating and LCM. With the developments in manufacturing technologies, interest on porosity graded alumina ceramics has increased for applications such as thick barrier coating, cores for precision casting and biocompatible implants. Lithography-based Ceramic Manufacturing (LCM) offers high quality and near-net manufacturing of complex ceramic components with high resolution. Multi-material LCM printing setup can overcome the main problems of conventional manufacturing techniques for fabrication of porosity graded alumina with desired microstructure and gradient architecture (i.e., gradient direction, fraction, type). Two-vat system in the newly developed multi-material LCM printer setup enables not only assigning one material to any desired layer but also use of different materials in each layer by assigning the respective materials to selected pixels of the layer image. This article introduces methodologies for the fabrication of porosity graded alumina ceramics (PGACs) with continuous and discrete porosity transitions zones by combining sacrificial templating and LCM. It is illustrated how the properties of the slurry and the desired gradient architecture play an important role for the selection of suitable method.

Heat Transfer Analysis of 3D Printed Wax Injection Mold Used in Investment Casting.

Investment casting is one of the precise casting methods where disposable wax patterns made in wax injection molds are used to make a casting mold. The production capacity of precision foundry is determined by the time taken for producing wax patterns, which depends on the time taken for wax solidification. Wax injection molds are usually made of aluminum or copper alloys with the use of expensive and time-consuming computer numerical control (CNC) processing, which makes low-volume production unprofitable. To reduce these costs, the authors present a heat transfer analysis of a 3D printed wax injection mold. Due to the low thermal conductivity of the photopolymer resin, the influence of different cooling channels’ shapes was investigated to improve the time of the manufacturing process. Transient thermal analysis was performed using COMSOL software based on the finite element method (FEM) and included a simulation of wax injection mold cooling with cold air (−23 °C), water, and without cooling. The analysis showed that use of cooling channels in the case of photopolymer material significantly reduces the solidification time of the sample (about 10 s shorter), and that under certain conditions, it is possible to obtain better cooling than obtained with the aluminum reference wax injection mold (after approximately 25–30 s). This approach allows to reduce the production costs of low-volume castings.

Thermomechanical fatigue and life prediction method of a precision cast superalloy with electrical discharge machining drilled holes

Thermomechanical fatigue behavior of a directional solidified superalloy was investigated. Circular holes were designed on the specimen manufactured by precision cast method. The results indicated that the TMF damage is mainly controlled by fatigue, creep and oxidation damage, and the stress concentration at the holes results in crack nucleation and final failure. A new TMF life prediction method for specimens with stress concentration is proposed. The stress gradient is introduced to consider the effect of stress concentration at hole and notch in this method, which is verified by TMF data of smooth, notched and hole specimens.

An improvement of manufacturing process using 3D printing technology for overhead line components on railway electrification

In an electric railway, an overhead contact system (OCS) is assembled with many components, and it maintains a voltage of 25 kV to supply electricity to the electric trains. As electric trains grow faster, the overhead line comes to employ a diverse range of materials to deliver electricity and maintain high tension. Overhead lines supply electricity to electric trains through mechanical contact with a pantograph, and since they are not fault-tolerant, they require high reliability. That makes it take a long time to develop and supply components and also makes it difficult and time consuming to apply new materials or new designs to components. This study proposes a manufacturing process for overhead line components using 3D printing technology. For this, a clevis terminal clamp for high-speed railway was chosen and a design drawing was created with 3D scanning. For molding, additive manufacturing technology was used. The study castings were obtained by applying precision casting and sand mold casting methods, respectively, and their elongation and tensile strength were compared with products made with a traditional method.

In-situ synthesis of high-performance Al2O3-based ceramic cores reinforced with core-shell structures

The complex structure of the ceramic cores is key to the preparation of an aero-engine hollow blade with excellent cooling performance. The traditional methods such as hot-press moulding are difficult to prepare complex-structured ceramic cores, and 3D printing technology provides a new idea for the preparation of complex-structured ceramic cores. Using SiO2 and Y2O3 as mineralizers in Al2O3-based ceramic cores, high-performance ceramic cores with a core-shell structure was successfully prepared by 3D printing. Additionally, the changes in microstructure and properties at different sintering temperatures were studied. The results showed that with an increase in the sintering temperature, a core-shell structure with Y2Si2O7 as the shell and Y2O3 as the core was formed, and the reinforced phases such as mullite were generated at the same time. The formation of core-shell particles suppressed the energy loss of cracks. The generation of the liquid phase led to the tight bonding of the Al2O3 particles. The synergistic effects of the core-shell structures and the reinforced phases enhanced the flexural strength. When the sintering temperature was 1380 °C, the comprehensive performance met the application requirements of the ceramic cores, and the flexural strength and porosity were 19.3 MPa (at 1500 °C) and 30.5%, respectively. The 3D-printed ceramic core by low-temperature sintering with a core-shell structure was successfully prepared, which promoted the wider application of DLP-3D printed ceramic cores technology in the field of precision casting. This is expected to reduce the energy consumption during the sintering process and promote the production of high-performance complex-structured ceramic cores.

Investment Casting Using FDM 3-D Printing

Abstract: The earliest casting method is investment casting, which dates back to roughly 3500 BC. Precision casting and near net form are two applications. Product demand is increasing in India and around the world. The use of simulation and rapid prototyping techniques in the investment casting process improves quality while reducing lead time and cost. However, as complexity increases, the traditional sand casting technique has limits, one of which is the expensive expense of equipment to make moulds and cores. These limitations can be solved by using a 3D printer, which offers the distinct advantage of geometric freedom. A polycast design is created in the precise shape of the item to be cast in this project. A refractory ceramic substance has been applied to this pattern. The metal is flown through a mould that is linked to the tree. The accuracy and surface finish of the models and castings were also assessed in order to provide a comparison. It has a significant impact on part quality (surface finish, dimensional correctness, strength, and longevity), as well as lead time and cost. In terms of remote pattern manufacture, it offers a lot of potential

Modification of the model compound with nanodiamond particles for precise investment casting of metal articles

Modification of the ZGV-101 model compound with nanodiamond particles, intended for precision casting of products from ferrous and nonferrous metals, produced by JSC Mining Wax Plant (Belarus), was carried out. Under laboratory conditions, a technology has been developed for introducing nanodiamond particles produced by the SP CJSC Sinta into the ZGV-101 model compound — the ASh-A brand diamond-containing charge and UDA SP brand ultrafine synthetic diamond. An assessment of the compatibility of nanoparticles with a model composition, depending on the method of its introduction has been carried out. Model compositions with different concentrations of nanoparticles were obtained, % (wt.): 0.005; 0.01; 0.05; 0.1. The heat resistance of ZGV-101 has been significantly improved; the dependences of softening temperature TS and Ubbelohde drop point TU on the concentration of nanoparticles were established, their nature was explained (a rapid increase in the heat resistance of model compounds at initial concentrations of 0.005% (wt.) and its subsequent decrease with a further increase in the content of nanoparticles). The reason for the increase in the heat resistance of the ZGV-101 model compound by nanodiamond particles at 0.001–0.005% (wt.) has been established. The hypothesis is related to the fact that at the given concentrations of nanoparticles, a spatial physical network is formed as a result of the interaction of the energetically active surface of nanoparticles with the carboxyl and hydroxide groups of components that make up ZGV-101. With an increase in the content of nanodiamond particles above 0.01–0.02% (wt.) in the composition, the uniformity of their distribution over the volume of the model compound is disturbed due to partial aggregation, and their connection with the functional groups of the composition components decreases.The paper is recommended to be published by the Organizing Committce of the International Symposium “Nanophysics and nanomaterials (November 24–25, 2021, St.Perersburg, St.Perersburg mining university).

Fast characterization framework for creep microstructure of a nickel-based SX superalloy with high-throughput experiments and deep learning methods

Nickel-based single crystal (SX) superalloys are the key materials of turbine blades in aircrafts, that the microstructure evolution during high temperature creep has critical effects on the thermo-mechanical properties. Research on microstructure evolution and establishing the quantitative relationship between microstructure evolution and creep conditions are of great significance for service safety assessment of nickel-based SX superalloys. High generation nickel-based SX superalloys generally have high cost on account of precision casting and the addition of Re and Ru which are rare and precious metals. Hence, it is necessary to develop a rapid characterization and analysis approach in terms of microstructure features of nickel-based SX superalloys. In this study, we integrated high-throughput experiment, large-scale high-resolution characterization and high-throughput quantitative analysis techniques to establish an efficient method for investigating the microstructure evolution of nickel-based SX superalloys during high temperature creep. The high temperature interrupted creep tests were carried out on the variable section specimens with arc surface to acquire the microstructures which are changed with creep stress continuously. High-resolution SEM with ALTLAS module was employed to quickly characterize the large-scale microstructure throughout the universal stress scale. Based on U-Net deep learning algorithm, an automatic dendrite identification model was established to segment the dendrite region quickly and accurately. And then, the γ/γ’ microstructure parameters of dendrite region were continuously quantitated using a logical algorithm. The quantitative correlation between microstructure evolution and creep conditions of nickel-based SX superalloys could be established, which shows tremendous potential and significance in the service safety assessment of nickel-based SX superalloys. • An integrated method is proposed for rapid characterization of microstructure features of SX superalloys. • The arc surface specimen can generate continuously distributed microstructure. • U-Net model can achieve dendrite region recognition quickly and accurately. • The γ/γ’ microstructure parameters were continuously quantitated using a logical algorithm.

RESEARCH OF THE UNIFORMITY OF THE COMPOSITION OF A CERAMIC PRODUCT DURING IMPREGNATION WITH A BINDER

In the production of aircraft parts by precision casting in ceramic molds, the key parameters are the uniformity of the composition and strength of ceramic molds associated with the technology of their manufacture. The technologically optimal strength of ceramics can be achieved using the technology of re-impregnation of a ceramic product with a binder, but in this case problems arise with the isotropy of the mechanical properties of the products. The paper presents the results of research and development of methods for regulating the uniformity of impregnation of ceramic samples with a secondary binder.

Anisotropy management on microstructure and mechanical property in 3D printing of silica-based ceramic cores

Ceramic core is an essential component in the precise casting of hollow turbine blades, and the investigation on 3D printing of silica-based ceramic cores is crucial to the development of aviation industry; however, they are suffered from difficulty in high-temperature strength and structural anisotropy. In present work, silica-based ceramic cores were prepared via DLP stereolithography 3D printing, and the anisotropy management on microstructures and properties were explored based on the particle size of fused silica powders. In 3D printed ceramic cores with coarse powders, significant anisotropy was displayed exhibiting multilayer structure with large gaps in horizontal printing and uniform porous microstructure in the vertical direction, which was further explained by the particle deposition in printing. With finer silica powders, the uniformity in the microstructures was highly improved, attributed to the enhanced particle dispersion in ceramic slurries and promoted interlayer particle rearrangement during sintering. To evaluate the anisotropy in mechanical property, the ratio of vertical strength to horizontal strength (σV/σH) was proposed, which rose from 0.48 to 0.86 as the particle size decreased from 35 µm to 5 µm, suggesting enhanced mechanical uniformity. While the average particle size of silica powders was 5 µm, the flexure strengths of ceramic cores in different directions were up to 18.5 MPa and 16.3 MPa at 1540 °C with σV/σH ratio of 0.88, which well satisfied the demands for the casting of turbine blades. This work inspires new guidance on the anisotropy management in ceramic cores prepared by 3D printing, and provides new technology for fabrication of silica-based ceramic cores with superior high temperature mechanical properties.

The Phenomena and Criteria Determining the Cracking Susceptibility of Repair Padding Welds of the Inconel 713C Nickel Alloy.

The creep-resistant casting nickel alloys (e.g., Inconel 713C) belong to the group of difficult-to-weld materials that are using for precise element production; e.g., aircraft engines. In precision castings composed of these alloys, some surface defects can be observed, especially in the form of surface discontinuities. These defects disqualify the castings for use. In this paper, the results of technological tests of remelting and surfacing by the Tungsten Inert Gas method (TIG) in an argon shield and TecLine 8910 gas mixture are presented for stationary parts of aircraft engines cast from Inconel 713C alloy. Based on the results of metallographic studies, it was found that the main problem during remelting and pad welding of Inconel 713C castings was the appearance of hot microcracks. This type of defect was initiated in the partial melting zone, and propagated to the heat affected zone (HAZ) subsequently. The transvarestraint test was performed to determine the hot-cracking criteria. The results of these tests indicated that under the conditions of variable deformation during the remelting and pad welding process, the high-temperature brittleness range (HTBR) was equal 246 °C, and it was between 1053 °C and 1299 °C. In this range, the Inconel 713C was prone to hot cracking. The maximum deformation for which the material was resistant to hot cracking was equal to 0.3%. The critical strain speed (CSS) of 1.71 1/s, and the critical strain rate for temperature drop (CST), which in this case was 0.0055 1/°C, should be used as a criteria for assessing the tendency for hot cracking of the Inconel 713C alloy in the HTBR. The developed technological guidelines and hot-cracking criteria can be used to repair Inconel 713C precision castings or modify their surfaces using welding processes.

ВЗАИМОДЕЙСТВИЕ ХИМИЧЕСКИ АКТИВНЫХ РАСПЛАВОВ С МАТЕРИАЛАМИ КЕРАМИЧЕСКИХ ФОРМ В ВАКУУМЕ

To obtain precise castings from chemically active melts, a special method of precision cas¬ting according to removable models is traditionally used, consisting in the manufacture of ceramic molds on an ethyl silicate binder and further filling with melt in vacuum. At the same time, when forming castings of a responsible purpose by pouring titanium and heat-resistant nickel alloys in a vacuum, the current technology causes a high defect due to the identification of various surface casting defects that are unacceptable when working parts under the action of repeatedly repeated temperature changes and alternating mechanical loads. The analysis showed that the main reason for this defect is the lack of thermochemical resistance of ceramic corundum molds on an ethyl silicate binder to interaction with poured titanium and heat-resistant nickel al-loys in vacuum. The possibility of obtaining high-quality castings from chemically active alloys is reduced to the use as a binder of ceramic forms of materials that are resistant to thermal dissociation in vacuum at heating temperatures of 1913–1973 K. For this purpose, it is proposed to use a silica-free binder – an aqueous solution of aluminum phosphate concentrate. The composition of the mold made according to the proposed technology, in which there is no silica, excluded the harmful effect of oxidation processes in vacuum on the quality of castings from chemically active alloys. Ceramic electrocorundum molds based on aluminum phosphate concentrate are resistant to thermal dissociation and interaction with chemically active metals poured in vacuum. This will reduce defects in non-metallic inclusions and improve the quality of precision castings made of titanium and heat-resistant nickel alloys.

Design, Simulation and Optimization of an Additive Laser-Based Manufacturing Process for Gearbox Housing with Reduced Weight Made from AlSi10Mg Alloy

The gas turbine engine’s (GTE) development aims for the increasing the efficiency, strength, reliability and safety of its components. To create competitive engines, housing parts and components with high functionality and reduced weight are needed. Especially difficult in the design and production are the gearboxes for aviation GTE. Traditional technologies based on precision casting or material forming operations have significant limitations due to the complexity of fulfilling multiple different requirements. Nowadays, one of the progressive production techniques is additive manufacturing. The article presents the results of computational and experimental studies that substantiate the applicability of laser additive technology to reduce the mass of body parts by up to 15% while ensuring their strength properties. The physical and mechanical characteristics of aluminum alloys acceptable for the manufacturing of housing parts were analyzed. The necessary characteristics of the powder alloy of the Al-Si system and the technological parameters of the L-PBF of the modified housing of the gear reducer are established. Using the finite element method (FEM) the L-PBF process was numerically simulated and the technological modes for synthesis of the AlSi10Mg alloy powder were optimized. With the help of a serial 3D printer ProX320DMP, the prototype of a gear housing was manufactured.

Minimizing the risk of fracture of definitive casts for removable partial dentures: A dental technique

A technique is described to facilitate impression making and safely obtain the definitive cast for removable partial dentures with long, retentive, or lone-standing abutment teeth. Firstly, the individualized stock tray receives a coating of melted wax. Next, the prepared teeth are impressed with irreversible hydrocolloid, and the set impression is removed from mouth. The mold is then poured conventionally and, after the gypsum has set, is immersed in hot water to soften the wax and allow removal of the tray. The impression material is carefully cut away with a scalpel blade to expose the cast. With these straightforward and easily made changes compared with the conventional technique, the risk of fracturing the definitive cast is minimized, especially when reproducing long retentive teeth. A dental technique is presented that uses wax to coat the impression tray to facilitate the passive displacement of the cast. This results in a straightforward and precise definitive cast for removable partial dentures.

Effects of 3 kinds of processing techniques on the fitness of metal clasp.

At present, removable partial denture is still one of the main restoration methods for dentition defects. However, the trend for digital partial denture is becoming more and more obvious in the field of oral repair. However, there are relatively few studies on digital removable partial denture. The aim of this study is to investigate the effects of 3 processing technologies (precision casting, digital cutting, and 3D printing) on the fitness for the clasps of cobalt chromium alloy and pure titanium removable partial denture, and to provide a theoretical basis for the clinical application of digital removable partial denture. Clasps of Co-Cr alloy and pure titanium were produced by 3 different processing technologies (precision casting, digital cutting, and 3D printing). There are 6 groups, including a casting pure titanium group, a casting cobalt chromium group, a cutting pure titanium group, a cutting cobalt chromium group, a printing pure titanium group, and a printing cobalt chromium group (n=6 per group). The gaps between the initial, middle, and tip of the lingual opposing arm of the clasp and the abutment were measured by fluorescent microscope, and the average value was taken as the index to measure the fitness between the clasp and the abutment. The fitness difference in three-arm clasp made of cobalt chromium alloy and pure titanium materials under 3 different technologies was compared. There was no statistical difference in fitness between the casting pure titanium group and the casting cobalt chromium group (P>0.05); there was no statistical difference in fitness between the cutting pure titanium group and the cutting cobalt chromium group (P>0.05); there was no statistical difference in fitness between the printing pure titanium group and the printing cobalt chromium group (P>0.05). When pure titanium was used, the fitness of the printing pure titanium group was the best (both P<0.05). There was no significant difference between the casting pure titanium group and the cutting pure titanium group (P>0.05). When cobalt chromium alloy was used, there was no significant difference in fitness among the 3 groups (P>0.05). The cobalt chromium alloy and pure titanium clasps made by precision casting, digital cutting, and 3D printing have good fitness. Under the same process, there is no significant difference between cobalt chromium alloy and pure titanium clasps. The 3D printing pure titanium clasps have better fitness than casting pure titanium and cutting pure titanium clasps, which meet the needs of clinical application.

Fabrication and properties of silica-based ceramic cores modified by mullite powders with different particle sizes

Ceramic cores provide complex internal cavity structures in the investment precision castings of hollow blades for aero-engine. The silica/mullite ceramic cores were fabricated by hot injection molding, adding fused mullite powders with different particle sizes as mineralizers. The particle size of mullite mineralizers on the crystallization and properties of ceramic cores was investigated in the paper. The result shows that the mullite mineralizers promote the crystallization of cristobalite in ceramic cores, and finer mullite powders can further improve the heterogeneous nucleation, and generate larger quantities of cristobalite. Mullite mineralizers with large particle size can lead to low sintering degree, poor mechanical properties and creep resistance of ceramic cores. While the particle size of mullite mineralizers is too small, the core contains too much quartzite crystal phase, and the microcrack occurs during the phase transformation during cooling, which also causes the deterioration of the strength at room temperature and the high temperature deformation resistance ability. The ceramic cores with mullite powders in particle size of 19 μm show excellent comprehensive performance, with linear shrinkage of 0.65%, porosity of 31.8%, room temperature strength of 17.8 MPa, high temperature creep deformation of 0.4 mm, and leaching rate of 0.06 g/min.