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Four process parameters were investigated with the aim of determining their influence on the mechanical properties of some test castings, bars, cylinders and plates. The influence was quantified in terms of percentage contribution. Analysis of variance (ANOVA), regression, main effects and interaction effects plots were employed to carry out the statistical analysis. As regards the tensile strength of the test castings, the geometry of components (GOC) dominated, contributing 90.83% and the pouring temperature (PT) contributed 91.90% influence on the hardness property. These dominating potentials of these twoparameters limited the interaction of the parameters studied in the research.

In this study, cast tungsten carbide particle/steel matrix surface composites were fabricated using a vacuum evaporative pattern casting (V-EPC) infiltration process. Through thermal shock tests at 500 °C, the initiation and propagation of cracks at the interface of the composites were investigated. Owing to the mismatch in the coefficients of thermal expansion (CTE), cracks tended to appear at the interface reaction zone (IRZ) between the particles and the matrix. Because there was also a difference in the CTE between the composite and the substrate, the cracks propagated rapidly along the transition layer (TL) between the composite and the substrate, and finally connected to form macro-cracks. Based on the stress analysis and calculation, the maximum thermal stress at the TL was 63.4 MPa, while the maximum thermal stress at the IRZ was 38 MPa. It could thus be inferred that the TL is the weak link under thermal fatigue. In addition, the experimental results were verified and found to be in good agreement with the calculations.

Cast tungsten carbide is widely used to reinforce iron or steel substrate surface composites to meet the demands of harsh wear environments due to its extremely high hardness and excellent wettability with molten steel. Cast tungsten carbide particle/steel matrix surface composites have demonstrated great potential development in applications under the abrasive working condition. The thermal shock test was used to investigate the fatigue behavior of the composites fabricated by vacuum evaporative pattern casting technique at different temperatures. At elevated temperatures, the fatigue behavior of the composites was influenced by the oxidation of tungsten carbide, producing WO3. Thermodynamic calculations showed that the W2C in the tungsten carbide particle was oxidized at an initial temperature of approximately 570 °C. The relationship between oxidation and thermal fatigue crack growth was investigated, and the results suggested that oxidation would become more significant with increasing thermal shock temperature. These findings provide a valuable guide for understanding and designing particle/steel substrate surface composites.

The vacuum evaporative pattern casting technique was used to fabricate WCp reinforced surface metal matrix composites in order to study the effects of Ni60WC25 powder content on the microstructure and wear properties of it. The results showed that the Ni60WC25 powders weakened the stability of WC particles and reacted with metal matrix at the interfacial regions in the composite. Diffusion kinetics and Gibbs free energy were calculated from the interactions between WC particles and matrix. It was found that adding 35 vol% Ni60WC25 alloy powder to composites led to the formation of Fe3W3C phases and complete dissolution of WC particles. The wear properties of composites with different Ni60WC25 alloy powder content were tested by the MLD-10 type tester. WC particles and Fe3W3C phases could protect the matrix and the matrix could support WC particles and Fe3W3C phases during wear processing.

Rapid casting gives the opportunity to develop a new casting in days, not in weeks or months. Evaporative Pattern Casting (EPC) process gives flexibility to produce complex geometries by integrating several parts in single casting. The lead-time and cost involved in designing and fabricating the metal tooling for Expanded Polystyrene (EPS) pattern making can be overcome by using the Segmented Object Manufacturing (SOM) machine. This hybrid system of pattern making is explored with all sub-systems and a complicated EPS pattern is produced by this Rapid Prototyping system. Conventional EPC process is more complicated due to coating development, vacuum assisted metal pouring and vibration system for filling the cavities by unbounded sand. In the present work, different mold-making processes are explored to avoid complications of conventional process. The Green sand, No-bake sand, and Plaster of Paris molds are prepared using Rapid Prototyped EPS pattern to produce the castings. The castings are characterized by comparing the surface roughness, dimensional accuracy, hardness, and surface morphology.

Molten metal filling rate and polystyrene foam pattern decomposition were examined in order to clarify how to improve the metal flow length of cast iron in the evaporative pattern casting process. The molten metal filling rate and the decomposition rate of a polystyrene foam pattern were measured during a casting experiment. A copper alloy was also cast using the same method for the purpose of comparison. The molten metal filling rate of cast iron was lower than that of the copper alloy. The volume of the gas gap increased with increasing melt temperature and decreasing coating permeability. A large amount of liquefied resin was formed by thermal decomposition of the foam pattern. The molten metal filling rate increased with increasing coating permeability and increased further with increasing coating thickness in the final step of molten metal filling. Even with increasing permeability of the coating, there is an occurrence of misruns in the case of molten cast iron, while the use of a thicker coating increased the molten metal flow length.

Taguchi’s approach to design of experiment was applied to determine the effect of some process parameters on the mechanical properties and microstructures of castings obtained by evaporative pattern casting process. Four process parameters with three levels were selected and used with Taguchi’s method to give nine experimental runs. Casting design system was employed to determine the gating parameters for each of the test castings in the study. The pattern material was polystyrene of density 2 g/cm3. The mechanical property tested where the ultimate tensile strength (UTS), percentage elongation and hardness value. It was observed that castings produced at pouring temperature of 650 °C had fine grains and the highest values of UTS and hardness values. There was a downward trend of these values as the pouring temperature increased from 650 to 700 °C and then to 750 °C. It was established that producing the Al alloy castings at pouring temperature close to 650 °C results in good mechanical properties and microstructures.

The service life of blast furnace (BF) is depending on the cooling equipment of furnace body, cooling stave which is an important cooling equipment for BF has attracted more attention. In the current paper, the classification of BF cooling staves in China was introduced, cast iron stave, cast steel stave, copper stave, and copper-steel composite stave were used on different parts of furnace body. The manufacture of cooling staves was studied, evaporative pattern casting (EPC) was favored due to high automation and environmental protection. The strong combination between steel plate and copper plate of copper-steel composite stave could be ensured under high-speed oblique impact through explosive welding. High density and high thermal conductivity of copper stave could be obtained by efficient rolling technology. The performance and application of BF cooling stave were investigated, the advantages and disadvantages of the various cooling staves were analysed, the thermal resistance between the steel water pipe and the cast iron body accounted for about 80% of the total thermal resistance which would affect the cooling effect of cast iron stave. The significant cost advantage of copper-steel composite stave was found compared with copper stave, test results of copper-steel composite stave in a commercial BF showed that the cooling effect is equivalent to that of the copper stave. The suitable cooling stave in BF should be selected according to the characteristics of the various cooling staves, the heat transfer balance and the stability of the skull on the hot face must be ensured to protect the cooling stave.

The possibility of using the new processing technique of vacuum evaporative pattern casting (V-EPC) process to fabricate the Al-Si based bonded diamond grinding wheels was explored in this paper. Distribution of diamond grits in the diamond/EPS composite pattern and in the grinding layer of the cast of the grinding wheel were analyzed. Microstructures and mechanical properties of the metal bonds and diamond composites fabricated by V-EPC process were studied. It is confirmed that thermal damage of the diamond grits did not occur. Strong bonding between metal bond and diamond grits can be produced. However, the uniformity of the distribution of diamond grits in the metal matrix should be further improved. Also, further hardening on the metal bond is necessity by trying other kinds of aluminum alloys.

This paper deals with the comparative study on the properties of Aluminium alloy (LM6-12%Si) castings in sand casting and Evaporative pattern casting (EPC) process. Thermocouples are used to measure the temperature of the casting during solidification. Signals from the thermocouples are connected to the DAQ (Data Acquisition Card) 6024E.The software development platform used for this application is LabVIEW. The signals acquired using DAQ card is given to the LabVIEW as an input. The acquired signals from the thermocouples are processed to obtain the mould filling and solidification time for both the process. Mechanical properties and micrographs of the castings were also considered. It is revealed that the properties of the evaporative pattern castings of A413 alloy are comparable to the castings.EPC is the viable alternate for conventional casting process to make intricate Al-Si Castings with energy efficient and environmental friendly way.

In order to provide significant references and theoretic base for the design and practical application of surface composites with high thermal fatigue performance, WC particles reinforced steel substrate surface composites were fabricated using vacuum evaporative pattern casting. And thermal fatigue behaviors of WC particles in the composites were investigated by stereomicroscope, X-ray diffraction and scanning electron microscopy. The results showed that the thermal fatigue failure of the WC particles in the composite was influenced by the combination of thermal stress and oxidation at high temperatures. When the thermal shock temperature was low (500 °C), the thermal stress was the major factor to influence the thermal fatigue failure. However, the oxidation particles played an important role with the increasing thermal shock temperature. The results might supply significant guides to the design of particles reinforced surface composites.

Tungsten carbide (WC) particle–reinforced iron matrix surface composites with different content of Cr were fabricated using vacuum evaporative pattern casting technique. It was found that the morphology of carbides changed from continuous net-shape to isolated block-shape patterns. The amount of carbides increase with the increasing Cr content in the matrices. Composites with different Cr content show better abrasive wear resistance than those without Cr. With the increase of Cr content in the matrices, the three-body abrasive wear resistance of the composites increased, while the impact abrasive wear resistance of the composites increased under 1 J impact load, but first increased and then decreased under 3 J impact load. The influences of the addition of Cr in the matrices on the abrasive wear resistance were the synergistic effects of two protecting effects and two supporting effects. The results might provide significant references for the design and practical application of WC particle–reinforced iron matrix surface composites.

In the whole process of the LFC (or evaporative pattern casting, EPC), the quality of the foam pattern play a decisive role to the final casting quality. The present processing methods for the foam pattern are discussed, including foaming molding, manual cutting, and CNC machining, rapid prototyping, also the advantages and disadvantages of these processing methods are analyzed. As CNC machining become the main trend for foam pattern processing, some CNC machine oriented tools are summarized, including the hot wire foam cutter, the hot knife foam cutter, and the modified tools based on the traditional tools.

In order to optimize the processing parameters of TiC/steel composite materials, in-situ TiC particle reinforced steel-based surface composites were prepared by vacuum evaporative pattern casting (V-EPC) infiltration process, and the structure and interface of the composites were investigated. The results show that, TiC particle size with Ti-C-20wt%Fe reaction system was much smaller than the composite with Ti-C reaction system in the same location of the composites. In the composites, the TiC particle size and volume fraction increased and spherical degree dropped from the tradition layers (interface between the substrate and the composite layer) to the outer surface. But the increase of TiC particle size (1-3μm) and volume fractions (25.8%-43.5%) in the composite with Ti-C-20wt%Fe reaction system was obviously lower than that of TiC particle size (1-10μm) and volume fractions (12.3%- 67.7%) in the composite with Ti-C reaction system. The bond zone between TiC particles and the matrices was totally metallurgical bonding without apparent interface. Comparing with the composite with Ti-C-xFe reaction system, the tradition layer with Ti-C reaction system has a poorer internal quality. The forming process of TiC in situ synthesized reinforced steel substrate surface composites prepared by V-EPC infiltrating process was infiltrating of the melting and carbothermal reactions of C and Ti powder the result of joint action.

Surface composite layer was fabricated on the cast steel matrix using the evaporative pattern casting (EPC) technology. The pre-coating with WC and Cr-Fe particles as raw reinforcements was reacted with matrix and formed the composite layer. Then, the microstructure and hardness of surface composite layer were investigated by Scanning Electron Microscope (SEM), Olympus Microscope (OM), Energy Dispersive X-ray Spectroscopy (EDAX) and Rockwell Apparatus. The results show that the composite layer can be divided into transitive layer and penetrated layer, and the component analysis shows that the microstructure distribution of the penetrated layer is homogeneous.

The influencing factors of surface alloying layer by evaporative pattern casting technology were investigated. A certain thickness alloying layer was formed on the surface of Mg-alloy matrix when the pouring temperature was 780 °C with different vacuum degree and alloying powder size. The surface layer microstructure, micro area composition of the new phase formed on the matrix and the composition characteristics on the surface layer were examined by SEM and element scanning. The results show that the content of aluminum increases greatly on the surface layer. The micro-hardness of alloyed layer has a more obvious increase compared with that of the matrix. The size of alloying element and the vacuum degree are the key factors influencing the alloying layer, with the increase of element powder size from 0.074 to 0.15 mm and vacuum degree from 0.04 to 0.06 MPa, the surface alloying effect becomes better.

The study develops a WC-Co rods reinforced based wear resistant composite by the combination of evaporative pattern casting (EPC) process and cast-in insertion method. And then the study investigates the interfacial microstructure between the reinforcement and substrate how to affect the abrasive wear behavior of the composites. It finds that wear resistance of austempered ductile iron (ADI) based composite gets three times of spheroidal graphite cast iron (SGI) not only due to the high performance of ADI, but also the excellent metallurgical bonding. The surface roughnesses of the substrate and the reinforcement in the samples correlate to their contribution rates on wear resistance. The high contribution rates (72.2%) of the substrate and the reinforcement obtained in the ADI based composite allow it possesses the best anti-wear performance. Consequently, the reinforcement protects the substrate from wearing, and the substrate efficiently supports the reinforcement, the stronger these collaborative effects, the more immune to the wear in severe condition.

In the production of the casting using evaporative pattern of expandable polystyrene, the refractory coating applied to the pattern is an extremely critical factor. The coating is not required merely to prevent a direct contact with the sand and metal. But its main task is to support the sand during the brief interval between the gasification and replacement of pattern by the molten metal. In the present study, refractory filler material (flyash) has been used for coating the evaporative polystyrene patterns. Effect of temperature on the powder mixture containing zircon flour, filler material and binder was determined using Differentially Thermal Analysis (DTA) in the range from ambient temperature (20 °C) to 1000 °C. Powder particle morphology was analyzed by the scanning electronic microscope. X-ray diffraction analysis of the coating samples was carried out for 2 θ values from 10° to 80°. Prepared slurry was applied on the polystyrene pattern of 20 kg/m 3 density. Coating thickness was maintained between 0.15 and 0.20 mm. Al–7% Si alloy was poured at the pouring temperature (700 °C). Microstructure of the casting was investigated. The result reveals that the sample 4 has less material loss. It contains large and small particles and fine pores. Particles of different grain size contribute to better uniform, continuous coating on pattern due to cohesion between the particles. The phases (ZrSiO 4 , TiO 2 , Fe 2 O 3 , Al 2 O 3 and SiO 2 ) make the stable compound which leads to high temperature refractoriness.

In the Evaporative Pattern Casting (EPC) process, the refractory coating plays an important role with the polystyrene pattern. It not only provides refractory protection to ensure no metal penetration and smooth surfaces, but it also acts as a membrane between the decomposing polystyrene pattern and the unbounded sand mass. In general zircon flour is used as a coating material in the EPC process but it is very costly. An attempt has been made to study the properties of the fly ash with the zircon flour and bentonite. The Taguchi design of experiments and analysis of variance (ANOVA) are employed to analyze the influence of the process parameters (Zircon flour, fly ash, and bentonite) on density of slurry of the coating material in the EPC process. In Taguchi method, a three-level orthogonal array has been used to determine the S/N ratio. The results reveal that the zircon flour, fly ash, and bentonite are the significant parameters. Zircon flour is the most significant factor influencing the response vari...

Evaporative pattern casting (EPC) process allows the production of complex parts and reduces machining of the part. To make a casting by EPC process, an expandable polystyrene pattern of the final part is made. In EPC process, all the limitations imposed by the binders and additives are absent as it is a binderless process. In this paper an attempt has been made to achieve a set of values of EPC process parameters that may yield optimum tensile properties to the Al–7% Si alloy castings. The effect of selected process parameters on the tensile properties of Al–7% Si alloy casting and subsequent optimal settings of the parameters have been obtained using Taguchi parametric design approach. The results indicate that the grain fineness number and the pouring temperature are the significant parameters in deciding the tensile strength and percent elongation after fracture of Al–7% Si alloy castings. Time of vibration and degree of vacuum are insignificant parameters. The predicted optimal value of tensile strength and percent elongation after fracture of Al–7% Si alloy castings produced by EPC process are 141.17 N/mm 2 and 2.713%, respectively, at 22 kg/m 3 density of expandable polystyrene pattern.

A336 Al matrix composites containing different volume fraction and mean mass particle size of SiC particles as the reinforcing phase were synthesised by evaporative pattern casting (EPC) route. The process consisted of fabricating of EPS/SiCp composite pattern followed by EPC of A336 Al alloy. The EPS/SiCp pattern was made by blending SiC particles with expandable polystyrene (EPS) beads and placing them in expanding mould heating with steam until EPS beads expand completely. Uniform distributed SiC particles around the EPS beads and locally movement of them during pouring and degradation leads to homogenous distribution of particles in final Al/SiCp composite. Higher modulus, strength and hardness were observed in the composites than the unreinforced Al alloy part. The fracture surfaces of the composite samples exhibited dimple surfaces and fracture in SiC particles.

The castings produced by the evaporative pattern casting (EPC) process have blow holes. The blow holes in EPC castings are because of the non-escape of the gas produced as a result of burning of polystyrene pattern in the sand mold. To overcome the problem of blow holes, the EPC process is combined with the vacuum (V)- process. The vacuum applied to EPC mold draws the decomposed gases and improves the casting quality produced by the EPC process. The developed hybrid process has been termed as the vacuum assisted evaporative pattern casting (VAEPC) process. The objective of this paper to investigates the effect of process parameters, i.e, degree of vacuum, pouring temperature, grainfineness number, amplitude of vibration and time of vibration on the impact strength of Al-7% Si alloy castings in VAEPC process. In order to evaluate the effect of selected process parameters, the response surface methodology (RSM) is used to formulate a mathematical model which correlates the independent process parameters with the desired impact strength. The central composite rotatable design has been used to conduct the experiments. The results indicate that the impact strength decreases with increases in the grainfineness number and pouring temperature. Whereas, it has an inverse relationship with amplitude of vibration, time of vibration and degree of vacuum. The best value of impact strength (2.34 N/mm2) has been obtained at 400 mm Hg degree of vacuum imposed, 650°C as pouring temperature, 60 as sand grainfineness number, 460 μm as amplitude of vibration, and 70 s as time of vibration.

Evaporative pattern casting (EPC) process has drawn great attention from both academia and industry in recent years. The expandable polystyrene (EPS) pattern is a key feature of EPC process which is buried in unbonded sand and replaced by molten metal. This paper investigates the effect of process parameters like degree of vacuum, pouring temperature, grainfiness number, amplitude of vibration and time of vibration on the surface roughness of Al–7% Si alloy castings in EPC process. In order to evaluate the effect of selected process parameters, the response surface methodology (RSM) is used to formulate a mathematical model which correlates the independent process parameters with the desired surface roughness. The central composite rotatable design has been used to conduct the experiments. The analysis of results indicates that the surface roughness increases with increase in degree of vacuum, pouring temperature. Whereas, it has an inverse relationship with grainfiness number, amplitude of vibration and time of vibration.

This paper fabricated tungsten carbide (WC) particles reinforced iron matrix surface composites on gray cast iron substrate using vacuum evaporative pattern casting (V-EPC) infiltration process, investigated dry three-body abrasive wear resistance of the composites containing different volume fractions of WC particles, comparing with a high chromium cast iron. The fabricated composites contained WC particles of 5, 10, 19, 27, 36, and 52 vol.%, respectively. The results in abrasive wear tests showed that, with the increase in the volume fraction of WC particles, the wear resistance of the composites first increased until reached the maximum when the volume fraction of WC was 27%, then decreased, and was 1.5–5.2 times higher than that of the high chromium cast iron. The changes of the wear resistance of the composites with the volume fraction of WC particles and the mode of material removal in dry three-body abrasive wear condition were analyzed.

In the present paper Taguchi's approach has been applied to the Evaporative Pattern Casting (EPC) process of Al–7%Si alloy to determine the most influential control factors which will provide better and consistent surface roughness to the castings regardless of the noise factors present. In order to evaluate the effect of process parameters such as grain fineness number, time of vibration, degree of vacuum and pouring temperature on surface roughness of EPC process castings, the Taguchi parameter design and optimization approach is used. Through the Taguchi's parameter design approach, optimal levels of process parameters have been determined. The results indicated that the grain fineness number, time of vibration, degree of vacuum were the significant parameters in deciding the surface roughness of Al–7%Si alloy castings. Pouring temperature was the insignificant parameter. The predicted optimal value of surface roughness of Al–7%Si alloy castings produced by EPC process was 2.31 μm. The results were confirmed by further experiments.

A magnesium alloy was adopted to an evaporative pattern casting (EPC) process to combine advantages of each. In the present study, foam patterns were cast at a top gating system under atmospheric and reduced pressure to evaluate casting characteristics of AZ91D to develop a complete EPC process for high productivity of magnesium alloy castings. Filling time and temperature of molten metal were measured during mold filling. It was recognized that the average filling velocity was affected by the difference of the coating material and the degree of reduced pressure. The grain size of the magnesium alloy was slightly dependent on the degree of reduced pressure. It was considered that the application of the high reduced pressure, which changed the shape of melt surface from convex to concave, was related to the occurrence of internal defects such as cold shut laps or folds in the casting.

We investigated thermal decomposition behavior of expanded patterns including thermal decomposition accelerators such as Ni, NiO, CuO and Cu 2 O (hereinafter referred to as powder-blended expanded patterns) in an aluminum alloy evaporative pattern casting process; the following results were obtained. When these metal or metal oxide powders were blended in EPS (expandable polystyrene) patterns, an exothermic reaction occurred between metal or metal oxide powder and aluminum alloy melt. This reaction prevented, temperature drop at the top of the melt flow. In addition, these kinds of powder accelerated pattern thermal decomposition. As a result, the pattern thermal decomposition gas volume increased and aluminum alloy melt filling decreased.

Metal or alloy powder capable of exothermic reaction with cast iron melt was blended into expandable polystyrene patterns. The behavior of thermal decomposition of the expandable patterns in evaporative pattern casting of cast iron was investigated. In evaporative pattern casting in which patterns including blended powder of metallic Si, Fe-Si alloy, Fe-Si-Mg alloy, or Fe-Si-Ca alloy were used, the temperature of the melt was higher than that in casting with original non-blended patterns. When the blending ratio was increased, the volume and pressure of decomposition gas during casting process were increased and, on the other hand, the filling rate of the melt was reduced. The use of patterns blended with powder caused no defect and abnormal structure in castings. These results imply that blending of metal or alloy powder into a pattern accelerates thermal decomposition of the pattern.

The paper describes research conducted to evaluate the influence of horizontal and vertical vibration on the movement of dry, unbonded silica sand in the evaporative pattern casting (EPC) process. ...

The filling of a moulding box with sand is one factor to affect the quality of castings for Evaporative Pattern Casting (EPC). The maximum filling height of the vertical tube is itself fairly sensi...

In the present paper Taguchi's Methodology has been applied to the Vacuum Assisted Evaporative Pattern Casting (VAEPC) process of Al-7%Si alloy to determine the most influential control factors. In order to evaluate the effect of process parameters such as grain fineness number, time of vibration, degree of vacuum and pouring temperature on percent deviation of VAEPC process castings, the Taguchi parameter design and optimisation approach is used. The results indicate that the grain fineness number, time of vibration, and degree of vacuum are significant. The predicted optimal value of % deviation of castings produced by the VAEPC process is 0.4172.

This study characterized the emissions generated during the pouring, cooling, and shakeout of castings made with the evaporative pattern casting (EPC) process. In addition, emissions from molds produced using conventional green sand technology were determined as a basis for comparison. Tests were performed under pilot-scale foundry conditions for production of both aluminum and gray iron water pump castings using an enclosing hood with a sampling stack. Sampling was conducted during pouring, cooling, and casting removal. Gas chromatographic/mass spectrometric (GC/MS) techniques and real-time instrumentation were used to identify the contaminants produced, to quantify the major contaminants, and to determine the temporal nature of these emissions. Major gaseous contaminants were identified as styrene, benzene, toluene, and ethyl benzene. Analysis of the real-time data indicated that the EPC molds produced more carbon soot and hydrocarbons during pouring than the green sand for both iron and alumin...