Expendable Pattern Casting Research Articles

Effect of Melt Velocity on Density of Aluminum Alloy Castings in Expendable Pattern Casting Process

Effect of Melt Velocity on Density of Aluminum Alloy Castings in Expendable Pattern Casting Process

Effects of Sand Material Type and Vibration Conditions on Appearance Quality of Aluminum Alloy Castings in Expendable Pattern Casting Process

Effects of Sand Material Type and Vibration Conditions on Appearance Quality of Aluminum Alloy Castings in Expendable Pattern Casting Process

Effect of Melt Velocity on Density of Aluminum Alloy Castings in Expendable Pattern Casting Process

Effect of Melt Velocity on Density of Aluminum Alloy Castings in Expendable Pattern Casting Process

TiC-Fe-Based Composite Coating Prepared by Self-Propagating High-Temperature Synthesis

TiC-Fe-based composite coatings were prepared in situ by self-propagating high-temperature synthesis combined with vacuum expendable pattern casting process. The band-like TiC phase embedded in a continuous Fe binder. There were no obvious defects and impurities at the interface between coatings and matrices. Fe presented consecutively in the coating zones and substrate zones without interruption and the microhardness in the cross-sectional area of the coating–matrix reduces continuously from the coating to the matrix area, indicating a good metallurgical bonding between the coatings and matrices. The effect of casting temperature on the microstructure and hardness of TiC-Fe-based composite coating was investigated in detail. The TiC particles formed at low casting temperature were nearly spherical in shape, and the size of TiC particles increased with increasing casting temperature due to more agglomeration. The hardness of the coatings increased first and then decreased with increasing casting temperature, and reached the highest value of 68 HRC when the casting temperature was 1773 K (1500 °C), which was twice more than that of the matrix.

402 消失模型鋳造法による薄肉アルミニウム合金鋳物の湯流れに及ぼす模型発泡倍率の影響(OS4-(1),OS4 オーガナイズドセッション≪材料・組織と加工≫)

The effects of the pattern expansion ratio and the pouring temperature on the mold filling for a thin wall aluminum alloy casting in the expendable pattern casting (EPC) process was investigated experimentally. An aluminum alloy plate was cast by the EPC process, and the fluid lengths of the molten metal were measured for two expendable polystyrene (EPS) pattern with different expansion ratios. When the thin EPS pattern is used, the fluid length of the melt is shorter, because of the increase of the heat release area per unit volume of the melt. When the coat permeability is less than approximately 2, the fluid length of the melt increases with increasing of the coat permeability. When the coat permeability is greater than approximately 2, because the melt velocity hardly increases even if the coat permeability increases, the increase of the fluid length of the melt is small. The use of the EPS pattern with a high expansion ratio led to the long fluid length of the molten metal. The reason for this may be the decrease of the temperature drop at the melt surface due to the increase of the melt velocity.

411 消失模型鋳造法におけるアルミニウム合金鋳物の密度に及ぼす鋳造方案と減圧の影響(OS4-(3),OS4 オーガナイズドセッション《材料・組織と加工》)

The effects of the casting design and reduced pressure in the flask on the density of an aluminum alloy casting in the expendable pattern casting (EPC) process were investigated experimentally. An aluminum alloy plate was cast by the EPC process, and the casting density was measured in order to evaluate the casting defect. The casting density tends to decrease, as the melt velocity is higher. The reason for this may be the increase of an involvement the liquid resin by the thermal decomposition of the model to the molten metal. In the case of bottom pouring, the casting density with reduced pressure is larger than that with no reduced pressure. In the case of top pouring, the casting density was larger than that for the bottom pouring, and the effect of the reduced pressure condition was not significant. From the result of observing the casting by an X-ray computed tomography (CT) imaging, the reason for the decrease in density of the casting may be a void by the residual resin defect.

Effects of Casting Design and Reduced Pressure on Mold Filling of Molten Aluminum Alloy in Expendable Pattern Casting Process

The effects of the casting design and reduced pressure in a flask on the mold filling of a molten aluminum alloy in the expendable pattern casting (EPC) process were investigated experimentally. An aluminum alloy plate was cast using the EPC process, and the arrival times of the molten metal were measured for three coats with different permeabilities. The use of a high permeability coat, or the condition of applying reduced pressure, led to a higher melt velocity. The melt velocity did not increase in proportion to the coat permeability. The experimental values for the arrival time of molten metal were compared with the calculated values based on the mold filling model used in the previous study. The values were in relatively good agreement except for when the coat permeability was very low. The arrival time in top pouring was almost the same as that in bottom pouring, except for when the coat permeability was very low. The melt velocity in the top pouring did not drop, even when the coat permeability was low. [doi:10.2320/matertrans.F-M2014834]

Design of the Typical Claw Structure Using the Technology of LFC

Based on the size of casting surface parts and the product quality, expendable pattern casting as a new casting method, it greatly improve production efficiency and save the manpower. With the cast process of mixing arm, as the study objective. It can preliminary identify the process plan by analysis of structure of workpiece surface and the casting process. It obtained the registered product under the considering of the main parameters and the rough size. The researched results can supply the reference value for the design and research of the expendable pattern casting.

Study on Sand Group Motion Characteristics of Vibration Moulding

Vibration moulding of expendable pattern casting (EPC) was simulated by three dimensional discrete element method, a special EPS tube for test was devised, and the law of vibration form on the motion of sand group was summed up. The results show that vibration form and filling motion of sand group in-tube has consistency in the direction, at the same time gravity and tube direction have a great influence on sand group motion, which leads to particularity of Z tube and Z vibration.

415 消失模型鋳造法におけるアルミニウム合金溶湯の湯流れに及ぼす模型発泡倍率の影響(OS9 オーガナイズドセッション《計算力学と数値シミュレーション》)

The Effects of the coat permeability and the expansion ratio of pattern on the mold filling of the molten aluminum alloy in the expendable pattern casting (EPC) process were investigated experimentally. An aluminum alloy plate was cast by the EPC process, and the filling time of the molten metal was measured for 3 kinds of pattern expansion ratios. The use of a high permeability coat or a high expansion pattern led to a larger melt velocity. The melt velocity does not increase in proportion to the coat permeability and the pattern expansion ratio. The experimental values of the melt velocity were compared with the calculated values based on the mold filling model by the previous study, and were in relatively good agreement with the calculated values for the case in which the coat permeability is under about 2. In the case the coat permeability is over about 2, the experimental values of the melt velocity were smaller than of the calculated values.

Application of CNC Programming Technology in the during of Processing for the Key Parts of Disappearing Mould

Disappearing mould casting is a new accurately processes with nearly free margin and precision forming, in which is no modulus, no parting, no sand core, so the casting without splash, burr and taper angle. It can improve the dimensional accuracy of the core portfolio for complex surface of the key compose of the disappearing mould. It has completed the design and manufacturing of these by the three-dimensional CAD/CAM technology, and obtains a series of effective methods and experience for the development of the products. The researched results have important directive to production practices for the design and machining process for the expendable pattern casting.

615 消失模型鋳造法におけるアルミニウム合金溶湯の湯流れに及ぼす塗型通気度と鋳造方案の影響(OS4-4 オーガナイズドセッション《材料・組織と加工》)

The Effects of the coat permeability and the casting design on the mold filling of the molten aluminum alloy in the expendable pattern casting (EPC) process were investigated experimentally. An aluminum alloy plate was cast by the EPC process, and the filling time of the molten metal was measured. The use of a high permeability coat or the application of the reduced pressure condition led to a larger melt velocity. The melt velocity does not increase in proportion to the coat permeability. The experimental values of the filling time of molten metal were compared with the calculated values based on the mold filling model by the previous study, and were in relatively good agreement with the calculated values except for the case in which the coat permeability is very small. The filling time in case of the top pouring almost same value as that in case of the bottom pouring, except for the case in which the coat permeability is very small. The melt velocity in case of the top pouring is not lowered, even if the coat permeability is small.

Effect of Coat Permeability on Temperature Drop of Molten Aluminum Alloy during Mold Filling in Expendable Pattern Casting Process

In the expendable pattern casting (EPC) process for the aluminum alloy casting, the thermal decomposition rate of the expendable pattern is smaller than the cast iron, therefore the misrun by the temperature drop at the melt surface occurs easily. This study takes account of the control of the heat release to the mold to investigate numerically and experimentally the effect of the coat permeability on the molten aluminum alloy temperature during mold filling in the EPC process. An aluminum alloy plate was cast by the EPC process, and the temperature change of the melt surface to the melt flow direction was measured. The use of high permeability coat led to a higher melt velocity and a smaller temperature drop at the melt surface than the case of the normal permeability coat. The temperature of molten metal filling into the cavity was numerically simulated, and the obtained temperature drop at the melt surface agreed relatively well with the experimental values. [doi:10.2320/matertrans.M2011242]

Study on Metallography and Properties of WC Cast-Infiltration on Carbon Steel Surface by Expendable Pattern Casting

With expendable pattern casting, WC infiltrated layer on carbon steel surface can be gained. Metallography of infiltrated layer was researched, hardness of infiltrated layer was tested and wear resistance was also tested on ML－100 attrition testing machine. Experimental results shoes that: microstructure of infiltrated layer is made up of pearlite, ferrite and WC particle, Brinell hardness of infiltrated layer is 1.7 times that of the matrix and wear resistance is 2.97 times that of the matrix.

602 消失模型鋳造法におけるアルミニウム合金鋳物の寸法精度に及ぼす塗型強度の影響(一般講演-(1)《ライフサポートにおける工学技術》)

The effect of coat strength on the dimensional accuracy of casting in expendable pattern casting (EPC) process was investigated experimentally. The aluminum alloy casting of the simple shape with the rib was cast by EPC process, and the dimensional change of the casting from the model was measured. When the sand was filled tightly, the dimensional accuracy and the appearance of the casting were good independently of the reduced pressure in the flask. When the sand was filled loosely, the positive different dimension of casting from the model was caused. Under the reduced pressure, this tendency was more remarkable and the leaching of the molten metal by the crack of the coat was observed. When the coat with high bending strength was used, even if the sand was filled loosely the different dimensions of the casting were small.

Effects of Ce and Sb on the microstructure and properties of AZ91D magnesium alloy prepared by the EPC process

The effects of small amounts of cerium and antimony additions on the microstructure and the mechanical properties of AZ91D (Mg-9A1-Zn) based alloy were researched via the expendable pattern casting (EPC) process. The results show that the microstructure is obviously refined and the tensile strength of the AZ91D based alloy at ambient temperature is significantly improved. When compared to AZ91D, the AZ91D-1.0%Ce-0.4%Sb alloy has higher ultimate tensile strength and elongation. Its ultimate tensile strength and elongation are enhanced by 39% and 47%, respectively. The morphology of the tensile fracture of the AZ91D-1.0%Ce-0.4%Sb alloy has more characteristics of quasi-cleavage. This indicates that it has had a larger plastic deformation before failure. The tensile strength and elongation decrease with the increase of Ce and Sb contents because of the coarsening and volume Increase of CeSb and Al 11Ce 3 phases.

Effects of Technological Factors on the Mold Filling Velocity of Magnesium Alloys in the Expendable Pattern Casting (EPC) Process

The effects of vacuum degree, pattern density, pouring temperature and metallic static head on the mold-filling velocity of AZ91D alloy in the expendable pattern casting (EPC) process have been investigated in the paper, and the influencing law of these technological factors on the mold-filling velocity are obtained. The results indicate that the influence of vacuum degree on the mold-filling velocity of AZ91D alloy in the EPC process is greatest, pattern density and pouring temperature are next respectively, and metallic static head is small relatively.

Mold-Filling Characteristics of AZ91 Magnesium Alloy in the Low-Pressure Expendable Pattern Casting Process

The magnesium (Mg) alloy low-pressure expendable pattern casting (EPC) process is a newly developed casting technique combining the advantages of both EPC and low-pressure casting. In this article, metal filling and the effect of the flow quantity of inert gas on the filling rate in the low-pressure EPC process are investigated. The results showed that the molten Mg alloy filled the mold cavity with a convex front laminar flow and the metal-filling rate increased significantly with increasing flow quantity when flow quantity was below a critical value. However, once the flow quantity exceeded a critical value, the filling rate increased slightly. The influence of the flow quantity of inert gas on melt-filling rate reveals that the mold fill is controlled by flow quantity for a lower filling rate, and, subsequently, controlled by the evaporation of polystyrene and the evaporation products for higher metal velocity. Meanwhile, the experimental results showed that the melt-filling rate significantly affected the flow profile, and the filling procedure for the Mg alloy in the low-pressure EPC process. A slower melt-filling rate could lead to misrun defects, whereas a higher filling rate results in folds, blisters, and porosity. The optimized filling rate with Mg alloy casting is 140 to 170 mm/s in low-pressure EPC.

Effects of Casting Conditions on the Mold Filling Characteristics of Mg Alloy in the EPC Process

Mold filling characteristics in the Mg Expendable Pattern Casting(EPC) process were investigated in terms of casting conditions such as reduced pressure, pouring temperature and casting modulus including foam materials. With increasing pouring temperature up to 775oC the filling velocity increased. However, the filling velocity decreased at temperatures above 775oC. This is likely due to the increase of back pressure. Concerning the effect of reduced pressure on filling velocity, it increased sharply at lower reduced pressure while became stable at higher reduced pressure. In thick pattern, high reduced pressure would be needed to obtain high filling velocity. In expanded polystyrene(EPS) patterns, mold filling was found to be faster in the thick pattern than thin pattern at temperatures below 750oC. This propensity was observed to be reverse at pouring temperatures above 750oC. In polymethyl methacrylate(PMMA) patterns, the filling velocity almost leveled off without showing a dependence of pouring temperature. This result is attributed to the difference in gas pressure between EPS and PMMA patterns during the EPC process.

Evaluation of the effect of vacuum on mold filling in the magnesium EPC process

The combination of magnesium alloys with the expendable pattern casting (EPC) process will bring a bright future for the application of magnesium alloys. Vacuum is a pre-requisite parameter in the EPC process of magnesium alloys, because without vacuum, the fluidity of the magnesium alloy in the EPC process is too poor to fill the mold completely, especially for the thin-section castings. In this investigation, the effect of vacuum on the fluidity of AZ91 magnesium alloy has been explored. A modified model has been presented to explain the effect of vacuum on mold filling, which was verified by optical microscopy. The results obtained indicate that vacuum is the most effective parameter in improving the fluidity, the effect of vacuum on the fluidity interacting strongly with the pouring temperature and coating. Vacuum greatly changes the mass and heat transfer in the EPC process. Vacuum may not only control the profile of the metal–foam interface, which will influence the mass transfer process, but may also greatly speed up the removal rate of pattern decomposition products at the metal–coating interface. It also changes the primary heat-transfer mode to heat convention, which has a great influence on the distribution of the casting temperature field and solidification process. The microstructures of castings cast with vacuum exhibit a fine grain size and a small amount of precipitated Mg 17Al 12, but vary insignificantly with the location in the castings.