Journal articles: 'Casting porosity'

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Říhová, M., J. Cech, and J. Havlíčková. "Evaluation of Porosity in Al Alloy Die Castings." Archives of Foundry Engineering 12, no. 1 (January 1, 2012): 93–98. http://dx.doi.org/10.2478/v10266-012-0018-9.

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Evaluation of Porosity in Al Alloy Die Castings Mechanical properties of an Al-alloy die casting depend significantly on its structural properties. Porosity in Al-alloy castings is one of the most frequent causes of waste castings. Gas pores are responsible for impaired mechanical-technological properties of cast materials. On the basis of a complex evaluation of experiments conducted on AlSi9Cu3 alloy samples taken from the upper engine block which was die-cast with and without local squeeze casting it can be said that castings manufactured without squeeze casting exhibit maximum porosity in the longitudinal section. The area without local squeeze casting exhibits a certain reduction in mechanical properties and porosity increased to as much as 5%. However, this still meets the norms set by SKODA AUTO a.s.

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Niakan, Ali Asghar, M. H. Idris, A. Ourdjini, and Majid Karimian. "Effect of Applying Air Pressure on Gas Porosity in Lost Foam Casting of Al-Si Alloy." Advanced Materials Research 628 (December 2012): 150–55. http://dx.doi.org/10.4028/www.scientific.net/amr.628.150.

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The paper presents the result of investigation on aluminum-silicon (LM6) alloy cast using pressurized lost foam casting process. The study investigated the effect of pressure and sand size on porosity of the casting produced. Air pressure of 1, 2, 3 and 4 bars was applied on the solidifying alloy poured in mould of sand sizes 16-30, 40-60, 60-100 (AFS). The porosities of casting were measured using optical microscope which was equipped with image analyzer. For porosity of castings, all surfaces of solidified castings were captured by digital camera for better observation. The results show that applying pressure during solidification of the LM6 alloy has significant influence on casting porosity of the alloy. By increasing the applied pressure, the porosity percentage based on gas porosity decreased when pressure was applied. Consequently, the removal rate of gas porosity improved by increasing the sand size to finer size 60-100 (AFS), so there is less gas porosity in samples. Besides, rising air pressure lead to fulfilling of molten which improves the casting porosity.

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Roskosz, Stanisław, Jacek Nawrocki, and Krzysztof Kubiak. "Porosity of Solid and Cored Turbine Blades of Aircraft Engines." Solid State Phenomena 226 (January 2015): 115–18. http://dx.doi.org/10.4028/www.scientific.net/ssp.226.115.

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Paper presents results of quantitative evaluation of porosity conducted on big, thin walled airfoil turbine blades made from Inconel 713C alloy. To decrease mass, blades are design and manufacture like thin walled cored castings. Manufacturing of big thin walled casting airfoil blades is extremely difficult. During exploitation casting work undergo cycle fatigue. In that cause casting should be free of casting defects, including porosity. Conducted research focused on Inconel 713C superalloy pouring temperature effect on porosity level of cored casted turbine blade. Results were compared to porosity of solid casted turbine blade. It was found that porosity of cored blades is lower than solid blade porosity. In cored blades higher porosity is located on airfoil convex side. Airfoil concave side has lower porosity.

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Boroń, Kinga. "Evaluation of porosity of AlZn5Mg castings made by squeeze casting technology." Acta Innovations, no. 32 (July 1, 2019): 12–19. http://dx.doi.org/10.32933/actainnovations.32.2.

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The paper shows the results of research aimed to assess the impact of high squeeze pressure on the porosity of AlZn5Mg alloy castings, including its distribution in slab-type castings with dimensions of 25 x 100 x 200 mm. The research was carried out on castings made by two methods: squeeze casting and gravity casting. The pressing was conducted at a pressure of 100 MPa at an initial mould temperature of 200°C. The research identified the middle and outer parts of the casting. Experimental research was preceded by numerical simulation of the casting solidification, then a porosity assessment was carried out using the hydrostatic weighing method, which was supplemented by structural observations. The results of the research showed a two-fold decrease in the porosity in the middle part of the casting which is most exposed to the occurrence of shrinkage voids formed in the final clotting phase. Structural tests revealed the occurrence of dispersed porosity in castings, mainly of shrinkage and / or shrinkage-gas origin. The impact of pressure of 100 MPa during solidification caused fragmentation of the primary structure of castings, which resulted in a higher grain density.

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Liu, Zi Kang, Min Luo, Da Quan Li, Long Fei Li, and Jian Feng. "Effects of Process Parameters on Shrinkage Porosity in 357 Semi-Solid Die Casting Parts." Materials Science Forum 993 (May 2020): 166–71. http://dx.doi.org/10.4028/www.scientific.net/msf.993.166.

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The shrinkage porosity that was caused by the insufficient feeding during solidification, was a common defect in the semi-solid die casting process. This defect decreased significantly the mechanical properties of the casting. In order to avoid the shrinkage porosity in casting, the die design, slug preparation and die casting process were carefully considered. In this study, a designed mold was used to make the sequential solidification of the slug. The process parameters, including intensification pressure, die temperature and biscuit thickness of the casting, were studied to show their influence on shrinkage porosity defects. The experimental results show that the high intensification pressure, high die temperature and long biscuit can be beneficial to obtain castings with no shrinkage porosity.

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Izman, S., Amirreza Shayganpour, and M. H. Idris. "Effect of Casting Parameters on Porosity in LFC." Applied Mechanics and Materials 148-149 (December 2011): 1198–201. http://dx.doi.org/10.4028/www.scientific.net/amm.148-149.1198.

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Cast aluminium alloys often contain microstructural defects resulting from the casting process such as porosity. Developments of Lost foam casting (LFC) process is considered as one of the most rapid in casting technology owing to its unique advantages on energy savings and capabilities to produce castings with thin sections. In the present research, experimental investigations in lost foam casting of aluminium-silicon cast alloy, LM6, were conducted. The main objective of the study was to evaluate the effect of different pouring temperatures, slurry viscosities, vibration times and sand sizes on the porosity of castings. A stepped pattern was used in the study and the focus of the investigations was at the thinnest 3 mm section. A full 2-level factorial design experimental technique was employed to plan the experiment and subsequently identify the significant factors which affect the casting porosity. The result shows that increasing in the pouring temperature decreases the porosity in the thin-wall section and finer sand size is more favourable than coarse size for LFC mould making process.

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Samavedam, S., and S. Sundarrajan. "Al-Si and Al-Si-Mg Cast Alloys Shrinkage Porosity Estimation." Archives of Foundry Engineering 16, no. 1 (March 1, 2016): 61–68. http://dx.doi.org/10.1515/afe-2016-0004.

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Abstract US A356 and US 413 cast aluminium alloys shrinkage characteristic have been discussed in the present study. Specific volume reduction leads to shrinkage in castings and it can be envisaged as a casting defect. Finite difference based casting process simulation software has been used to study the shrinkage characteristic and it is quantified using mathematical formulae. The three dimensional model of the shrinkage defect has been constructed using CAD application software. Shrinkage characteristic has also been quantified through experimental validation studies and compared well with casting process simulation. Shrinkage characteristic study and control is essential for producing defect free castings. Influence of casting shape on the shrinkage characteristic has been studied in this paper.

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Nadolski, M., Z. Konopka, M. Łągiewka, and A. Zyska. "The Influence of the Mould Filling Conditions on the Quality of Castings Made of EN AC-44000 Alloy." Archives of Foundry Engineering 14, no. 2 (June 1, 2014): 19–22. http://dx.doi.org/10.2478/afe-2014-0029.

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Abstract The work deals with the influence of change in the filling conditions of the ceramic moulds with plaster binder on the presence of gaseous porosity and the microstructure of the achieved test castings with graded wall thickness. Castings made of EN AC-44000 alloy, produced either by gravity casting, or by gravity casting with negative pressure generated around the mould (according to the Vacumetal technology), or by counter-gravity casting were compared. The results of examinations concerning the density of the produced castings indicate that no significant change in porosity was found. The increased size of silicon crystals was found for the increased wall thicknesses due to the slower cooling and solidification of castings.

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O'Donnell, Robert G., Dayalan R. Gunasegaram, and Michel Givord. "Die Casting Improvements through Melt Shear." Materials Science Forum 618-619 (April 2009): 33–37. http://dx.doi.org/10.4028/www.scientific.net/msf.618-619.33.

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Melt flow and solidification within a die casting cavity is a complex process dependent in part on melt pressure (with or without intensification), melt velocity, melt flow path, thermal gradients within the die, die lubrication and melt viscosity. Casting defects such as short shots, cold shuts and shrinkage porosity can readily occur if casting conditions are not optimised. Shrinkage porosity in particular is difficult to eradicate from castings that comprise thick sections, since these sections will usually solidify late in the casting cycle and may be starved of melt supply during the critical solidification (and contraction) stage. The current work seeks to elucidate the influence of the melt shearing on the die casting process and demonstrates that the modifications made to the melt through introduction of a local constriction in the melt path can generate improvements in casting microstructure and reduce shrinkage porosity.

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Izman, S., Amirreza Shayganpour, M. H. Idris, and Hassan Jafari. "DOE Analysis of the Influence of Sand Size and Pouring Temperature on Porosity in LFC." Applied Mechanics and Materials 121-126 (October 2011): 2661–65. http://dx.doi.org/10.4028/www.scientific.net/amm.121-126.2661.

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Lost foam casting is a relatively new process in commercial terms and is widely used to produce defect free castings owing to its advantages like producing complex shape and acceptable surface finish. In the present research, experimental investigations in lost foam casting of aluminium-silicon cast alloy, LM6, were conducted. The main objective of the study was to evaluate the effect of different sand sizes and pouring temperatures on the porosity of thin-wall castings. A stepped pattern was used in the study and the focus of the investigations was at the thinnest 3 mm section. A full 2-level factorial design experimental technique was employed to plan the experiment and subsequently identify the significant factors which affect the casting porosity. The result shows that increasing in the pouring temperature decreases the porosity in the thin-wall section of casting. Finer sand size is more favourable than coarse size for LFC mould making process.

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Dong, Yi, Xiao Ming Fan, and Bin Liu. "Numerical Simulation and Technology Optimization of Rear Oil Seal Bearing Die Castings Based on ProCAST." Advanced Materials Research 189-193 (February 2011): 4008–13. http://dx.doi.org/10.4028/www.scientific.net/amr.189-193.4008.

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In production,the Φ105 mm hole of rear oil seal bearing die castings often appear porosity, shrinkage and other defects , resulting in the parts to scrap. The existing gating system design of rear oil seal bearing die castings was improved , and the flow and temperature field of the two programs that before and after improvement were analyzed by ProCAST software. The simulation results predicted the casting defects, and the conclusion was consistent with the production. By using the improved process optimization, the rejection rate of die castings can be reduced effectively. Die casting is a chipless forming of casting with high casting dimensional accuracy, high surface quality and high production efficiency [1,2]. Therefore, it has developed rapidly in the automotive, communications and other industries. However, due to shrinkage, porosity and other reasons, leading to high rejection rate of castings. With the emergence of commercial casting simulation software, the casting production has been developed from semi empirical and semi theoretical onto theorization, quantification and controllable track[3-5]. In this paper, the casting defects of rear oil seal bearing is analyzed by using numerical simulation technology[6]. By optimizing the casting process, the casting quality is improved, and the rejection rate is reduced effectively.

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Sadayappan, K., W. Kasprzak, Zach Brown, L. Quimet, and Alan A. Luo. "Characterization of Magnesium Automotive Components Produced by Super-Vacuum Die Casting Process." Materials Science Forum 618-619 (April 2009): 381–86. http://dx.doi.org/10.4028/www.scientific.net/msf.618-619.381.

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Magnesium automotive components are currently produced by high pressure die casting. These castings cannot be heat-treated to improve the strength and ductility mainly due to the casting imperfections such as porosity and inclusions created by the air entrainment during the turbulent mold filing. These imperfections also prevent magnesium components to be used for highly stressed body components. Efforts were made to produce high integrity magnesium castings through a Super-Vacuum Die Casting process. The AZ91D castings were found to have very low porosity and can be heat-treated without blisters. The tensile properties of the castings were satisfactory. The mechanical properties and thermal analysis indicate that the conventional heat treatment procedure needs to be optimized for such thin sectioned and rapidly solidified castings which have very fine microstructures.

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13

Huang, Pei Hsing, Wei Jen Wu, and Chung Han Shieh. "Numerical Simulations of Low Pressure Die-Casting for A356 Aluminum Rims." Materials Science Forum 893 (March 2017): 276–80. http://dx.doi.org/10.4028/www.scientific.net/msf.893.276.

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This study conducted mold flow analyses on low pressure die-casting A356 aluminum rims to improve the shrinkage and porosity defects which usually occurs in die-castings so as to enhance the quality of die-casting wheels. We adopted different lift tube designs with cylindrical, taper opening and back taper opening structures while discussing the filling, exhaust, and solidification of molten flows and predicting the shrinkage and porosity formed based on the retained melt modulus. The study found that the configuration of lift tube as well as the optimization of process parameters such as the processing pressure and progressive time could effectively reduce the formations of shrinkage and porosity defects and improve the quality of die-castings.

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Zyska, A., Z. Konopka, M. Łągiewka, and M. Nadolski. "Porosity of Castings Produced by the Vacuum Assisted Pressure Die Casting Method." Archives of Foundry Engineering 15, no. 1 (March 1, 2015): 125–30. http://dx.doi.org/10.1515/afe-2015-0023.

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Abstract The paper presents the results of investigations concerning the influence of negative (relative) pressure in the die cavity of high pressure die casting machine on the porosity of castings made of AlSi9Cu3 alloy. Examinations were carried out for the VertaCast cold chamber vertical pressure die casting machine equipped with a vacuum system. Experiments were performed for three values of the applied gauge pressure: -0.3 bar, -0.5 bar, and -0.7 bar, at constant values of other technological parameters, selected during the formerly carried initial experiments. Porosity of castings was assessed on the basis of microstructure observation and the density measurements performed by the method of hydrostatic weighing. The performed investigation allowed to find out that - for the examined pressure range - the porosity of castings decreases linearly with an increase in the absolute value of negative pressure applied to the die cavity. The negative pressure value of -0.7 bar allows to produce castings exhibiting porosity value less than 1%. Large blowholes arisen probably by occlusion of gaseous phase during the injection of metal into the die cavity, were found in castings produced at the negative pressure value of -0.3 bar. These blowholes are placed mostly in regions of local thermal centres and often accompanied by the discontinuities in the form of interdendritic shrinkage micro-porosity. It was concluded that the high quality AlSi9Cu3 alloy castings able to work in elevated temperatures can be achieved for the absolute value of the negative pressure applied to the die cavity greater than 0.5 bar at the applied set of other parameters of pressure die casting machine work.

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15

Ignaszak, Zenon, and Jakub Hajkowski. "Gas- and Shrinkage Porosities in Al-Si High-Pressure Die-Castings - Virtualization and Experimental Validation." Defect and Diffusion Forum 364 (June 2015): 80–91. http://dx.doi.org/10.4028/www.scientific.net/ddf.364.80.

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The porosity (void caused by technological reasons) in engineering materials always decrease their mechanical characteristics and usually affects the deterioration of the functional mechanical characteristics of the finished products. In the castings the porosity resulting from the specific casting processes phenomena occurs inevitably in the matrix structure. The paper shows this problem in relation to the High-Pressure-Die-Casting (HPDC) technology of Al-Si alloy. The analysis of the experimental results and the results from virtualization of HPDC process allowed to assess the effectiveness of this mixed scenario and improve the quality predictions probability for HPDC, with particular consideration of shrinkage and gas porosities. The problem of the tolerance (admissibility) of porosity occurrence in castings and the castings made of liquid Al-Si alloy to which the gas (hydrogen) was introduced intentionally are signalized.

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Kuo, Yeong Sant. "Study of Solidification Time and Solidus Velocity on Porosity Formation in High Strength Aluminum Alloy Castings." Applied Mechanics and Materials 575 (June 2014): 442–45. http://dx.doi.org/10.4028/www.scientific.net/amm.575.442.

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The purpose of the present study was to discuss the effects of local solidification time and solidus velocity on porosity formation in high strength aluminum alloy casting. With systematic change in the riser size, together with variation of thickness and length, A201 aluminum alloys were cast in 100% silica sand molds. The porosity content of A201 aluminum alloy was affected by the local solidification time and solidus velocity in this study. The correlation between porosity content and solidification time is found to be split into 2 bands, each being associated with one of the two thicknesses of plate castings. The longer the solidification time, the more the porosity content was measured in the A201 aluminum alloy plate casting. And the faster the solidus velocity, the more the porosity content in this study. The porosity content of A201 aluminum alloy was influenced by both of solidification time and solidus velocity at same time in this study. Basically, shorter local solidification time with slow solidus velocity seems get lower porosity content in A201 aluminum alloy castings.

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Suprapto, Wahyono, Bambang Suharno, Johny Wahyuadi Soedarsono, and Dedi Priadi. "Analytical and Experimental Models of Porosity Formation of Duralumin Cast in Vacuum Casting System." Advanced Materials Research 277 (July 2011): 76–83. http://dx.doi.org/10.4028/www.scientific.net/amr.277.76.

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Porosity in cast metals often leads to cracking of components due to stress concentration and leakage, and as the result, the castings need be repaired or rejected. Disharmony in casting process was resulting in porosity. Prediction of porosity in the casting is necessary as a step to avoid the waste products and reduce costs. But to ensure whether these predictions are accurate and precise, it is still necessary to validate the test trials and testing. This paper aims to provide early information when, where, and how large a defect occurs in particular foundry casting porosity on duralumin. The analytical study of porosity formation based analytic equilibrium wt% of element, the behavior of the thermodynamic, hydrodynamic, and rules of metallurgical on vacuum casting of duralumin. Experiments as a validation study are conducted by duralumin remelting on stainless-steel bowl in a vacuum casting furnace. Analytical simulation and experiments of the casting that has been vacuumed by melting 10 cmHg pressures higher than the pressure solidification, and duralumin melt is poured automatically into permanent mold carbon steel. In the study cast duralumin created five different thicknesses. Both these studies assume the addition of copper (2.5%, 3.0%, 3.5 %, 4.0%, and 4.5% Cu) and vacuum pressure (76, 50, 40, cmHg), as independent variables, while dependent variable in the studies is porosity characteristics, which includes morphology, number and dimensions of the porosity. Optical emission spectrometry test, Reynold's and Niyama numbers, Sievert's law, Archimedes' principle (Pycnometry and Straube-Pfeiffer tests), and Eichenauer equation are instruments which are used to determine the characterization of duralumin casting porosity. Duralumin ingots remelting process was performed by the control pressure (p1) and temperature (T1). Vacuuming process performed after the smelting room temperature reaches 600 °C. Once melted, it followed by duralumin into a permanent mold (p2, T2). As a control parameter is the height of pouring (7 cm), pour temperature and mold temperature respectively at 750 °C and 300 °C. The porosity characteristics studies of two models produce two types of porosity (gas and shrinkage), the quantity dimension and porosity, and distribution of porosity in the cast duralumin.

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Ignaszak, Z., and J. Hajkowski. "Contribution to the Identification of Porosity Type in AlSiCu High-Pressure-Die-Castings by Experimental and Virtual Way." Archives of Foundry Engineering 15, no. 1 (March 1, 2015): 143–51. http://dx.doi.org/10.1515/afe-2015-0026.

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Abstract The paper concerns the problem of discontinuity in high pressure die castings (HPDC). The compactness of their structure is not perfect, as it is sometimes believed. The discontinuities present in these castings are the porosity as follow: shrinkage and gas (hydrogen and gas-air occlusions) origin. The mixed gas and shrinkage nature of porosity makes it difficult to identify and indicate the dominant source. The selected parameters of metallurgical quality of AlSi9Cu3 alloy before and after refining and the gravity castings samples (as DI - density index method), were tested and evaluated. This alloy was served to cast the test casting by HPDC method. The penetrating testing (PT) and metallographic study of both kinds of castings were realized. The application of the NF&S simulation system allowed virtually to indicate the porosity zones at risk of a particular type in gravity and high-pressure-die-castings. The comparing of these results with the experiment allowed to conclude about NF&S models validation. The validity of hypotheses concerning the mechanisms of formation and development of porosity in HPDC casting were also analyzed.

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Fintová, Stanislava, Giancarlo Anzelotti, Radomila Konečná, and Gianni Nicoletto. "Casting Pore Characterization by X-Ray Computed Tomography and Metallography." Archive of Mechanical Engineering 57, no. 3 (January 1, 2010): 263–73. http://dx.doi.org/10.2478/v10180-010-0014-y.

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Casting Pore Characterization by X-Ray Computed Tomography and MetallographyCasting porosity is the main factor influencing the fatigue properties of Al-Si alloys. Due to the increasing use of aluminum castings, porosity characterization is useful for estimating their fatigue strength. In principle, a combination of metallographic techniques and statistical pore analysis is a suitable approach for predicting the largest defect size that is critical for the casting. Here, the influence of modifiers and casting technology on the largest pore size population in AlSi7Mg alloy specimens is obtained and discussed adopting the Murakami's approach. However, porosity evaluation is a challenge in the case of microshrinkage pores, which are frequently found in industrial castings. Their complicated morphology prevents a reliable definition of an equivalent defect size based on metallographic techniques. This contribution reports the application of X-ray tomography to the 3D reconstruction of real pores in cast Al-Si alloys and provides insight into the complication of microshrinkage pore sizing by metallography.

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Sumpena, Sumpena. "Pengaruh Paduan Serbuk Fe12% pada Aluminium terhadap Porositas dan Struktur Mikro dengan Metode Gravity Casting." Jurnal Engine: Energi, Manufaktur, dan Material 1, no. 1 (May 31, 2017): 20. http://dx.doi.org/10.30588/jeemm.v1i1.225.

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<em>The purpose of this research is to know the effect of Fe12% powder alloy on aluminum to porosity and micro structure by gravity casting method. Metal Matrix Composite (MMC) is an engineering material formed from the combination of two or more materials to obtain new materials with better properties. Making of composite material with aluminum matrix or metal matrix composite (MMC) can be done by casting method. The composite forming elements are called boosters (fibers or particles) and binders (matrices). In the process of casting metal can occur porosity In the casting process with sand molds usually occur porosity, causing the mechanical properties of casting objects decreased. Porosity is caused by bubbles of gas, gas released by the core when exposed to metal liquid heat, resulting in pores or perforated defects.The process of smelting was carried out at the metal foundry laboratory of Mechanical Engineering UP 45 Yogyakarta. The smelting process uses a krusible furnace with coke fuel, on which it is placed kowi to place aluminum and iron powder to be melted. Aluminum and 12% iron powder are weighed in accordance with the volume of the pattern, so that the melt does not suffer from metal deficiency. Observation of porosity is done by looking visually on each side of the outer part of the casting object. Observation of microstructure using optical microscope is done by taking three samples of specimen castings that have been in the preparation of polishing machine and etching. The effect of Fe 12% alloys on porosity is the average porosity occurring on specimens A, B and C of 2,766 gr / cm3. The effect of Fe 12% alloys on micro structure is the spreading of Fe, Si and Mg elements evenly, but for the C specimens of Fe and Si bersenyawa, while the Al and Mg elements are separate.</em>

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Chen, Yi, Gang Yang, Yi Yang, Kang Sheng Wang, and Chen Guang Lu. "Casting Process and Simulation of K19 Cylinder Block." Applied Mechanics and Materials 602-605 (August 2014): 311–15. http://dx.doi.org/10.4028/www.scientific.net/amm.602-605.311.

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Cylinder blocks are the most important parts of engine, and their qualities will fundamentally determine the efficiency of engine. In this work, the casting process of K19 engine cylinder block was studied. A casting process was designed and assessed by the numerical software MAGMA to produce cylinder block castings. An actual experiment of casting was carried out and the mechanical properties of the casting were examined. The simulation results show the liquid metal smoothly fills the casting mold and no shrinkage cavity and porosity are formed in the castings. The cylinder block produced by the actual experiment exhibits superior mechanical properties to common ones, which proves the casting process designed is suitable for producing high quality cylinder block castings. The research shows that numerical simulation can provide very useful guidance for the production of castings

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Eliopoulos, Dimitris, Spiros Zinelis, and Triantafillos Papadopoulos. "Porosity of cpTi casting with four different casting machines." Journal of Prosthetic Dentistry 92, no. 4 (October 2004): 377–81. http://dx.doi.org/10.1016/j.prosdent.2004.07.006.

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Sulaiman, Shamsuddin, M. K. A. M. Ariffin, S. H. Tang, and A. Saleh. "Influence of Pattern Coating Thickness on Porosity and Mechanical Properties of Lost Foam Casting of Al-Si (LM6) Alloy." Applied Mechanics and Materials 300-301 (February 2013): 1281–84. http://dx.doi.org/10.4028/www.scientific.net/amm.300-301.1281.

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The combination of Aluminum alloy with lost foam casting (LFC) process is best applied in automotive industry to replace steel components in order to achieve light weight components for reducing fuel consumption and to protect the environment. The LFC process involves process parameters such as the degree of vacuum, foam degradation, expanded polystyrene (EPS) foam density, permeability of foam pattern coatings, pouring temperature, filling velocity, cooling rate, and pressure. The effect of polystyrene foam pattern coating thickness on the porosity and mechanical properties of Aluminum Al-Si LM6 alloy were evaluated experimentally. The coating thickness was controlled by slurry viscosity at range between 18sec to 20sec using Zahn viscosity cup No.5 and the foam pattern was coated up to fifth layer. Aluminum Al-Si (LM6) molten metal was poured into expandable mould and castings were examined to determine porosity distribution, mechanical properties and microscopic observation. Results from X-ray testing reveal the porosity distribution on Aluminum Al-Si LM6 castings is greater at thicker foam pattern coating sample. Meanwhile, the tensile strength of casting decreases when foam pattern coating thickness increases. Microscope observation portray the present of porosity on the casting which shows more gas defects present at thicker foam pattern coating sample. The source of porosity in LFC process is due to air entrainment or the entraining gases from polystyrene foam decomposition during pouring of molten metal. As a conclusion, mechanical strength has inverse relationship with porosity.

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Ignaszak, Zenon, and Jakub Hajkowski. "Identification of Casting Conditions Influence on the Structure and Properties of Al-Si-X Alloy Castings by Experimental and Virtual Way." Defect and Diffusion Forum 367 (April 2016): 110–20. http://dx.doi.org/10.4028/www.scientific.net/ddf.367.110.

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The paper describes influence of the structure type and its parameters on the mechanical properties of cast products (not subjected to plastic forming), made out of Al-Si-X alloys. The special attention has been focused on the dendritic structure parameters: dendritic arms spacing of the first order (DAS 1) and the second order (DAS 2). The results of investigations of mechanical properties of the test castings made using three basic casting technologies: gravity sand casting (GSC), gravity die casting (GDC) and high pressure die casting (HPDC), are presented. All the castings were made out of the same AlSi9Cu3 alloy. The test castings (adherent samples and separately cast samples) were subjected to a static tensile test and their mechanical properties were determined. In the next stage, the samples fractures and zones near the fractures (metallographic specimen) were subjected to visual testing, penetrating testing PT and metallographic microscopic tests. The microstructure, including the size of the DAS 2, was determined. Evaluation of the porosity state was also undertaken. A customer casting was also manufactured and subjected to the metallographic, tomographic (CT) and strength tests. The castings solidification simulation tests were performed for all the three casting technologies (GSC, GDC and HPDC) using the Nova Flow &Solid system. The results were used for estimation of the correlation between the cooling rate of the particular casting solidifying in the above mentioned mould types and for the DAS size. The coupled influence of the structure parameters on the mechanical properties, regarding the occurrence of porosity, was also analyzed.

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Santos, Jorge, Anders E. W. Jarfors, and Arne K. Dahle. "Filling, Feeding and Defect Formation of Thick-Walled AlSi7Mg0.3 Semi-Solid Castings." Solid State Phenomena 256 (September 2016): 222–27. http://dx.doi.org/10.4028/www.scientific.net/ssp.256.222.

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Aluminium semi-solid castings have gained increased attention due to their superior mechanical properties, lower porosity compared to conventional high pressure die cast material. These characteristics suggests that semi-solid casting should be suitable to produce thick-walled structural components, yet most successful applications of semisolid casting have been for thin-walled components. There is a lack of understanding on filling and feeding related defect formation for semi-solid castings with thick-walled cross-sections. In the current study an AlSi7Mg0.3 aluminium alloy was used to produce semi-solid castings with a wall thickness of 10mm using a Vertical High Pressure Die Casting machine. The RheoMetalTM process was used for slurry preparation. The primary solid α-Al fraction in the slurry was varied together with die temperature. The evaluation of the filling related events was made through interrupted shots, stopping the plunger at different positions. Microscopy of full castings and interrupted test samples were performed identifying the presence of surface segregation layer, shear bands, gas entrapment, shrinkage porosity as well as burst feeding.

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Choudhari, C. M., K. J. Padalkar, K. K. Dhumal, B. E. Narkhede, and S. K. Mahajan. "Defect Free Casting by Using Simulation Software." Applied Mechanics and Materials 313-314 (March 2013): 1130–34. http://dx.doi.org/10.4028/www.scientific.net/amm.313-314.1130.

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The use of Aluminum castings parts in the automotive industry has increased dramatically over the past few decades. The driving force for this increased use is vehicle weight reduction for improved performance. In many cases the mechanical properties of the cast aluminum parts are superior to those of the cast iron or wrought steel parts being used.This paper proposes the computer simulation of the sand casting of Aluminum Plate. It aims to study the behavior of fluid flow during mould filling and solidification and to optimize the process parameters, which help to predict and control casting defects such as gas porosity and shrinkage porosity. Here an attempt is being made to model and simulate the casting process using the AutoCAST software. The technological as well as practical aspects of using casting software are illustrated with an industrial case study.

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You, Ming, and Xiao Gang Diao. "Simulation of Casting Process for Ductile Iron Wind Generator Rotor Shaft." Advanced Materials Research 567 (September 2012): 141–45. http://dx.doi.org/10.4028/www.scientific.net/amr.567.141.

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Casting process of heavy section ductile iron wind generator rotor shaft was simulated by finite element software ProCAST. Gating systems was designed according to the structure of the casting. Solidification behavior of the casting was then analyzed. Defects, especially porosity, of the casting during solidification were predicted and hence casting process optimization has been performed based on the simulation results in order to avoid porosity in the casting. Results show that solidification time of the casting is more than 14h when cooled in sand mold. Porosity easily formed at the thermal center and in the middle of flange. Solidification time is evidently decreased with the help of chills. However, porosity tendency depends on the position of chills. A ductile iron rotor shaft casting with good quality was finally produced according to the simulation results.

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Gašpár, Štefan, Tomáš Coranič, Ján Majerník, Jozef Husár, Lucia Knapčíková, Dominik Gojdan, and Ján Paško. "Influence of Gating System Parameters of Die-Cast Molds on Properties of Al-Si Castings." Materials 14, no. 13 (July 5, 2021): 3755. http://dx.doi.org/10.3390/ma14133755.

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The resulting quality of castings indicates the correlation of the design of the mold inlet system and the setting of technological parameters of casting. In this study, the influence of design solutions of the inlet system in a pressure mold on the properties of Al-Si castings was analyzed by computer modelling and subsequently verified experimentally. In the process of computer simulation, the design solutions of the inlet system, the mode of filling the mold depending on the formation of the casting and the homogeneity of the casting represented by the formation of shrinkages were assessed. In the experimental part, homogeneity was monitored by X-ray analysis by evaluating the integrity of the casting and the presence of pores. Mechanical properties such as permanent deformation and surface hardness of castings were determined experimentally, depending on the height of the inlet notch. The height of the inlet notch has been shown to be a key factor, significantly influencing the properties of the die-cast parts and influencing the speed and filling mode of the mold cavity. At the same time, a significant correlation between porosity and mechanical properties of castings is demonstrated. With the increasing share of porosity, the values of permanent deformation of castings increased. It is shown that the surface hardness of castings does not depend on the integrity of the castings but on the degree of subcooling of the melt in contact with the mold and the formation of a fine-grained structure in the peripheral zones of the casting.

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Huang, Pei Hsing, Wei Jen Wu, and Chung Han Shieh. "Compute-Aided Design of Low Pressure Die-Casting Process of A356 Aluminum Wheels." Applied Mechanics and Materials 864 (April 2017): 173–78. http://dx.doi.org/10.4028/www.scientific.net/amm.864.173.

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The lightweight design of aluminum automobile wheel can easily bring about all kinds of defects during die-casting, which often causes wheel frame deformation and creep damages in the future use and in turn affects traffic safety. To understand the evolution of mold flow, temperature field, and solidification, the low pressure die-casting processes of A356 aluminum wheel were simulated by Anycasting software package. Various casting parameters combined with the designs of flow channel and overflows were adopted to reduce the defects occurred in wheel products. In addition, we adopted the retained melt modulus (RMM) to predict the position of defects to be formed as well as their distribution so as to eliminate the shrinkage voids and porosity defects during die-casting. The research findings showed that the setting up of overflow tank could effectively prevent the formation of shrinkage void and porosity of die-castings and significantly promote the quality and productivity of die-casting wheel products.

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Gaspar, Stefan, and Ján Pasko. "Analysis of Fracture Process and Common Defects in Casting Alloys EN43100 Manufactured by Die Casting Technology." Advanced Materials Research 1077 (December 2014): 39–43. http://dx.doi.org/10.4028/www.scientific.net/amr.1077.39.

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Recent research in the process of die casting production of aluminium alloys which are nowadays deeply implemented in the rapidly developing automobile, shipping and airline industry aims to increase the manufacture and quality properties of the casting in order to obtain its high mechanical properties at acceptable economic costs. In terms of ensuring the quality indicators in the production of aluminium castings it is necessary to pay close attention to internal structural quality of the castings characterized by type and extent of foundry defects (cavities, Al2O3 particles, internal cold laps). The presenting contribution deals with the analysis of the fracture process, the microorganism disturbance of test samples, the impact of casting speed on the occurrence and extent of the castings porosity and reasons for the internal foundry defects of casting alloys EN 43100 manufactured by die casting technology.

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Anastasiou, K. S. "Optimization of the aluminium die casting process based on the Taguchi method." Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 216, no. 7 (July 1, 2002): 969–77. http://dx.doi.org/10.1243/09544050260174175.

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Porosity in the die casting process causes costly scrap loss and limits the use of die-cast parts in critical high-strength applications. The amount of porosity is closely related to the die casting process parameters. Consequently, the mechanisms of porosity formation in relation to die casting parameters have to be studied in detail. A considerable reduction in porosity formation can be obtained by Taguchi technique implementation in the die casting process. Through simple multifactorial experiments in the foundry, controllable factors can be isolated to provide centring and variance control for a process variable. The primary objective of this paper is to investigate the effects of process parameters on porosity formation in the pressure die casting process to improve casting quality. Examples of the off-line technique used in a Greek aluminium die casting company are given for the purpose of illustrating the practicality and ease of use by industry engineers and managers.

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Gil-Duran, S., D. Arola, and E. A. Ossa. "Control of Porosity in Freeze Casting." JOM 72, no. 4 (January 2, 2020): 1477–86. http://dx.doi.org/10.1007/s11837-019-03974-y.

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Mozammil, Shaik, Jimmy Karloopia, and P. K. Jha. "Investigation of porosity in Al casting." Materials Today: Proceedings 5, no. 9 (2018): 17270–76. http://dx.doi.org/10.1016/j.matpr.2018.04.138.

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Fan, P., S. L. Cockcroft, D. M. Maijer, L. Yao, C. Reilly, and A. B. Phillion. "Porosity Prediction in A356 Wheel Casting." Metallurgical and Materials Transactions B 50, no. 5 (July 11, 2019): 2421–35. http://dx.doi.org/10.1007/s11663-019-01642-9.

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Nagendran, N., N. Gayathri, V. K. Shanmuganathan, and S. Praveen. "Effects of Nano Particles on the Microstructure of LM 25 (A356) Alloy Manufactured by Squeeze Casting." Applied Mechanics and Materials 867 (July 2017): 64–70. http://dx.doi.org/10.4028/www.scientific.net/amm.867.64.

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Conventional casting process cannot produce parts as strong as forged parts. Also there are chances of many casting defects such as porosity, hot tears, shrinkage, pin holes, blow holes, mould shift flash, slag, short casting, when casting method is used for fabrication. Thus cast parts only have low mechanical properties. Recent trend is to use Squeeze Casting, which results in superior mechanical and casting properties. This technique is a hybrid metal forming process combining features of both casting and forging in one operation. This process is suitable for low melting alloys like iron and nickel with mechanical properties enhancement. Reduction in micro porosity in cast part and also reduction in machining. Historically, the series of LM were developed for high strength, corrosion resistance, and good machinability for many applications. In this study Squeeze Casting process has been used, since it has porosity free equiaxed grain components of LM 25 composition and cylindrical shaped castings were manufactured successfully by squeeze casting machine at high temperature and high pressure. The first part of the study is about the microstructure of the LM 25 Al-7 Si-0.3 Mg-0.5 Fe alloy. The casting products were made by addition of nano particles and without nano particles. The size of bar casted was by squeeze casting process. It was 260 mm*46mm (7 Pieces). Microstructure of Cast without squeeze and without stirrer, without squeeze and with stirrer, with squeeze and with stirrer Alloys was studied. The second part of the work was the heat treatment process of the finished product. Heat treatment process was conducted at 490○C and for the heat treated metals was quenched at 30○C (water) for the heat treated and unheated metal casting product were taken and microstructure were studied. The results were compared before and after the heat treatment process for addition of nano particles and without nano particles.

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Huang, Yao, Yue Dong, and Yong Huang. "Shell Die-Casting and its Process Based on Numerical Simulation." Advanced Materials Research 233-235 (May 2011): 1167–70. http://dx.doi.org/10.4028/www.scientific.net/amr.233-235.1167.

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In this paper, the distribution and variation trend of temperature and velocity fields were obtained by numerical simulation of the casting process of shell die casting. According to the results of the numerical simulation, the die casting technology was optimized. The sound castings were produced. It was verified that shrinkage cavity and porosity could be reduced by increasing injected pressure and decreasing pouring and mould temperatures. The reliability of numerical simulation of die casting process was proved. In addition, the qualified products were obtained on the basis of the optimized die-casting parameters from the simulation results.

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Zheng, Liang, Guo Qing Zhang, Dominik Daisenberger, Zhou Li, and Cheng Bo Xiao. "The Effect of Process Parameters in Interdendritic-Melt Solidification Control Technique on the Microstructure and Properties of a Ni-Base Superalloy." Materials Science Forum 879 (November 2016): 1129–34. http://dx.doi.org/10.4028/www.scientific.net/msf.879.1129.

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A novel technique called interdendritic-melt solidified control (IMSC) was developed to manufacture equiaxed superalloy in the efforts of reducing porosity. The effect of process parameter, such as withdrawal rate, of the IMSC on the porosities and mechanical properties of IN792 alloy was investigated, compared with conventional investment casting (CC) technique. The IMSC and CC samples were characterized by optical metallography and scanning electron microscopy. In addition, the minor phases, such as MC carbides and trace amount of η phase, were identified by synchrotron X-ray diffraction. The results indicate that proper withdrawal rate for IMSC can produce castings with much reduced porosity and higher stress rupture properties at elevated temperature compared to conventional investment casting. However, fast withdrawal rate will produce much severe porosity and lower mechanical property.

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Zhao, Hai Dong, and Bai Cheng Liu. "Prediction of Microstructure and Porosity Formation of Practical Spheroidal Graphite Iron Castings." Key Engineering Materials 457 (December 2010): 349–54. http://dx.doi.org/10.4028/www.scientific.net/kem.457.349.

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The mathematical model for microstructure formation and porosity prediction during solidification process of SG iron casting was established and applied to a practical brake housing casting. Quantitative microstructure analysis of specimens machined from the castings was compared with the simulation, and the two results are in acceptable agreement on nodule counts and size, pearlite fractions and hardness. It is indicated that the model can calculate the fraction of ferrite and pearlite more accurately, and specially can reflect the effect of both under-cooling during solidification and the nodules formed in eutectic period on the pearlite content. The present porosity prediction was compared with those of a former method and commercial software, which leads to that the current methods used for porosity prediction should be investigated and improved further.

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Paško, Ján, and Štefan Gašpár. "Progressive Trends of Die Casting - Vacuum Treatment of Casting Mold." Key Engineering Materials 669 (October 2015): 103–9. http://dx.doi.org/10.4028/www.scientific.net/kem.669.103.

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In these days in foundry branch there is a rapid development of sectors of special casting technology with the aim to increase the quality and the efficiency of pressure casting production. Internal homogeneity of pressure casting, characterized by the extent of porosity can be affected by the setup of technological parameters of pressure casting and last but not least by vacuuming the moulds, that means to exhaust air and gases from the mould cavity. Contribution is specifically aimed on the analysing the impact of degassing pressure moulds on the porosity of pressure casting from EN AC43400 Alloy.

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Szalva, Péter, and Imre Norbert Orbulov. "Influence of Vacuum Support on the Fatigue Life of AlSi9Cu3(Fe) Aluminum Alloy Die Castings." Journal of Materials Engineering and Performance 29, no. 9 (August 27, 2020): 5685–95. http://dx.doi.org/10.1007/s11665-020-05050-y.

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Abstract High-pressure die casting (HPDC) is a near-net-shape process that produces high quality castings with narrow dimensional tolerances. The HPDC castings are being increasingly used due to good flexibility and high productivity, especially for the automotive industry. Depending on the location of the cast components, there are ever more complex geometries and increasing strength requirements that can be achieved by the application of vacuum-assisted die casting (VPDC). The most specific features of the HPDC process are the rapid mold filling, high cooling rate and intensification pressure. As a consequence of these highlighted features, the process generally leads to the formation of casting defects, such as gas porosity, shrinkage, and entrapped oxide films. However, the VPDC casting process is capable to significantly reduce the amount of these casting defects. The aim of this work is to compare the HPDC and VPDC castings’ high-cycle fatigue behavior and to describe how the casting defects affect the fatigue failure. Before the fatigue tests, the samples were investigated with non-destructive (NDT) materials testing methods such as hydrostatic weighing, x-ray, and computer tomography (CT) to characterize the gas pore and shrinkage pore populations of the material. The AlSi9Cu3(Fe) aluminum alloy castings have been subjected to constant amplitude load by uniaxial fatigue tests in the high-cycle fatigue region with a stress asymmetry ratios of R = −1 and R = 0.1. The resulting fracture surfaces are analyzed through light optical microscopy (LOM) and scanning electron microscopy (SEM). VPDC increased the number of cycles to fracture and decreased the scatter at the given load levels compared to conventional HPDC casting. Moreover, VPDC significantly decreased the porosity size and volume, and the occurrence of oxide flakes is also decreased, resulting in the improvement in the number of cycle to failure.

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Papanikolaou, Michail, Emanuele Pagone, Konstantinos Georgarakis, Keith Rogers, Mark Jolly, and Konstantinos Salonitis. "Design Optimisation of the Feeding System of a Novel Counter-Gravity Casting Process." Metals 8, no. 10 (October 11, 2018): 817. http://dx.doi.org/10.3390/met8100817.

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The appropriate design of feeders in a rigging system is critical for ensuring efficient compensation for solidification shrinkage, thus eliminating (shrinkage-related) porosity and contributing to the production of superior quality castings. In this study, a multi-objective optimisation framework combined with Computational Fluid Dynamics (CFD) simulations has been introduced to investigate the effect of the feeders’ geometry on shrinkage porosity aiming to optimise casting quality and yield for a novel counter-gravity casting process (CRIMSON). The weighted sum technique was employed to convert this multi-objective optimisation problem to a single objective one. Moreover, an evolutionary multi-objective optimisation algorithm (NSGA-II) has been applied to estimate the trade-off between the objective functions and support decision makers on selecting the optimum solution based on the desired properties of the final casting product and the process characteristics. This study is one of the first attempts to combine CFD simulations with multi-objective optimisation techniques in counter-gravity casting. The obtained results indicate the benefits of applying multi-objective optimisation techniques to casting processes.

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Gaspar, Stefan, Jan Pasko, and Dusan Knezo. "The Influence of the Tablet Height and Plunger Pressing Velocity on the Final Porosity of Die Casting." Materials Science Forum 916 (March 2018): 244–48. http://dx.doi.org/10.4028/www.scientific.net/msf.916.244.

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With a pressure die casting process, one of the important factors affecting the quality of castings represented by porosity is plunger pressing velocity determines the regime die cavity filling and correct determination of dose mass of a molten metal required for one casting cycle. The mass is given by a total of the net mass of a casting, overflows, a gate system and a metal rest inside a filling chamber (the tablet height). As a rule, the tablet height represents the largest mass ratio regarding the waste metal. A correct determination of the tablet height is important from both economical and qualitative aspect of a pressure die casting process.

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Kuo, Y. S. "Effects of Thermal Gradient and Solidification Time on Porosity Content of A201 Aluminum Alloy Castings." Advanced Materials Research 503-504 (April 2012): 597–600. http://dx.doi.org/10.4028/www.scientific.net/amr.503-504.597.

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The purpose of the present study was to discuss the effects of local solidification time and thermal gradient on porosity content in long solidification range A201 aluminum alloy plate castings. With systematic change in the riser size, together with variation of thickness and length, were cast in different kinds of molds. The sand molds with end chill for the plate castings were made of 100% silica sand. The porosity content of A201 aluminum alloy was affected by the local solidification time and thermal gradient at same time in this study. The correlation between porosity content and any individual thermal parameter is found to be split into 2 bands, each being associated with one of the two thicknesses of plate castings. The higher the thermal gradient, the lower the porosity content was measured in the A201 aluminum alloy plate casting. And high thermal gradient with short solidification time will get lower porosity content in aluminum alloy castings

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Jou, Rong Yuan. "Investigations of the High Vacuum Die Castings of Dumbbell Specimens." Materials Science Forum 628-629 (August 2009): 727–34. http://dx.doi.org/10.4028/www.scientific.net/msf.628-629.727.

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Compare to atmosphere die casting or moderate vacuum die casting process, use of the high vacuum die casting can enhance excluding gas volumes in the mold, improve the casting mechanical properties and density, and increase the fabrication feasibility for casting small feature size, shape, and higher quality of product. The process of high vacuum die casting for dumbbell specimens is established and implemented for evaluation of this innovative manufacturing technology. A transparent acrylic mold is fabricated to investigate the vacuum injection for vacuum die casting process and a metal mold is fabricated to test the real manufacturing of high vacuum die casting. To visualize the flowing pattern inside the mold under the consequence of evacuation processing, flow visualization experiments are conducted. Then, the specimen is molded by the high vacuum die casting process and the specimen castings are test by a universal testing machine for its loading-elongation relationship. The porosities of specimen casting are examined by scale weighting and direct visual inspection ways. Experimental results show that the high vacuum die casting process is effective to reduce the porosity (5.47% increment in weight) and to increase the strength (4.83% increment in maximum stress) of the investigated specimen. An obviously vortex roll is established along the centerline position of dumbbell specimen which may be became the source of porosity in real processing. Meanwhile, an excellent vacuum sealing is critical to the success of high vacuum die casting.

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Chang, Qing Ming, Jing Yuan, Yin Kai Yang, and Xia Chen. "Modeling Analysis and Optimization of Sand Casting Process." Advanced Materials Research 479-481 (February 2012): 226–29. http://dx.doi.org/10.4028/www.scientific.net/amr.479-481.226.

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In this research paper, the sand casting process of a cover-type part for wind turbine was investigated with ProCAST software . The cover-type casting part is big in two dimensions and it is heavy in some local positions where shrinkage cavity and porosity are very likely to from. A non-uniform mesh is used corresponding to the non-uniform wall thickness. Different casting processes are employed, simulated and optimized to obtain sound castings. Simulation results reveal that with appropriate pouring temperature, correct number, size and location of chills and risers, a smooth mold filling, reduced shrinkage and other defects are available and desired sound castings can be produced

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Thanabumrungkul, S., W. Jumpol, Rungsinee Canyook, N. Meemongkol, and Jessada Wannasin. "Characterization of Microstructure and Shrinkage Porosity of a Semi-Solid Metal Slurry in Gravity Die Casting." Solid State Phenomena 285 (January 2019): 161–66. http://dx.doi.org/10.4028/www.scientific.net/ssp.285.161.

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Current aluminum automotive parts such as wheels, engine and transmission components are produced by tilted gravity die casting for control gas porosity. But, there are still problems resulting in inefficient production: shrinkage porosity, microstructure size and uniformity. Shrinkage porosity is one of the major issues which affects mechanical properties such as strength and elongation in tilted pour permanent mold. Recent work using slurry casting technique has shown potential in gravity sand casting. Results show that the casting parts have complete filling at low solid fractions and the casting yield is also higher than conventional gravity sand casting. This paper extends important work for potential industrial applications in gravity die casting: microstructure size, uniformity, solid fraction control for micro shrinkage level.

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Kuo, Yeong Sant. "Mechanical Properties and Porosity Content of A201 Aluminum Alloy Castings in Different Cooling Rate Sand Molds." Advanced Materials Research 154-155 (October 2010): 787–93. http://dx.doi.org/10.4028/www.scientific.net/amr.154-155.787.

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A201 aluminum alloy plate castings with systematic change in the riser size, together with variation of thickness and length, were cast in different kinds of molds to find out the influence of cooling rate on the mechanical properties and porosity content. The sand molds with end chill for the plate castings were made of 100% silica sand (type A mold), 50%silica sand/50% chromite sand (type B mold) and 100% chromite sand (type Cmold). Both the porosity content and mechanical properties of A201 aluminum alloy plate casting are governed by the cooling rate. Both of tensile strength and elongation are reduced when the porosity content becomes more.

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Kuo, Yeong Sant. "Influences of Thermal Gradient and Solidus Velocity on Porosity Content in A201 Aluminum Alloy Castings." Applied Mechanics and Materials 496-500 (January 2014): 255–58. http://dx.doi.org/10.4028/www.scientific.net/amm.496-500.255.

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With systematic change in the riser size, together with variation of thickness and length, A201 aluminum alloys were cast in 100% silica sand molds. The higher the thermal gradient, the lower the porosity content was measured in the A201 aluminum alloy plate casting. And the faster the solidus velocity, the more the porosity content in this study. The porosity content of A201 aluminum alloy was influenced by both of thermal gradient and solidus velocity at same time in this study. Basically, high thermal gradient with slow solidus velocity seems get lower porosity content in A201 aluminum alloy castings.

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Liu, Jin Xiang, Ri Dong Liao, and Zheng Xi Zuo. "Numerical Study on Solidification Process and Shrinkage Porosity for Engine Block Casting." Applied Mechanics and Materials 37-38 (November 2010): 753–56. http://dx.doi.org/10.4028/www.scientific.net/amm.37-38.753.

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The latent heat releasing and the criterion for shrinkage porosity in solidification progress of casting are studied. A numerical analysis is presented for solidification progress of the cylinder head casting using finite element method. The temperature distributions of the casting in different solidification phases are solved, and the shrinkage porosity is predicted. Based on this, the solidification progress of casting is evaluated. The simulation results can offer a helpful reference for casting design of cylinder head casting.

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Zhang, Guang Sheng, and Fei Zhang. "Casting Process Solutions Optimization of LFC Forklift Box." Applied Mechanics and Materials 571-572 (June 2014): 1091–96. http://dx.doi.org/10.4028/www.scientific.net/amm.571-572.1091.

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There are many advantages in producing forklift box through the LFC. However, we found shrinkage porosity defects in the interior of castings through simulating the original process by ProCAST casting simulation software. Therefore, we analyzed the defects and improved the technology program. firstly, increased riser in position of shrinkage, Secondly, changed the filling’s way, lastly, selected the best temperature and vacuum by the orthogonal experiment and determined the best technology solution. we found the shrinkage porosity defects have been removed by the improved process. We found the production consistent with the simulation results through verification. Therefore we verify the accuracy of the ProCAST.

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Journal articles on the topic 'Casting porosity'

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