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Journal articles on the topic 'Metal castings'
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1
Zhengwuvi, L. B., and A. O. Akii Ibhadode. "Risering of a Four-Cavity Die Production Mould by Convectional Method." Advanced Materials Research 62-64 (February 2009): 664–70. http://dx.doi.org/10.4028/www.scientific.net/amr.62-64.664.
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This paper demonstrates the possibility of developing skill in producing sound metal casting from a four-cavity die production mould by assessing the riser design criteria and the castings. The assessment takes into account the location of the casting’s hot spots, casting modulus, liquid metal mass in the risers and the principle of directional solidification. The mould flask is oriented in such a way that a riser is placed directly on top of the casting’s hot spots for proper feeding during solidification. The assessment result of casting modulus shows that the feeder modulus Mf = 5.85 x 10-3 M and the casting hot spot modulus Mh = 1.88 x 10-3 M .The assessment result of castings solidification time shows that the castings solidify within 12 seconds while the feeders solidify within 30 seconds. From the assessment results it is observed that the risers hold liquid metal, feed the castings to full solidification and solidify later than the castings which they feed. Examinations at the cross sections of the finished castings revealed the absence of void formation which is a clear indication of effective and functional risers. Thus, the risers have achieved the desired requirement.
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Prasanna, BG, M. Kalavathi, Bhuvana Sachin, TV Shreeharsha, B. Praveen, and Mallikarjuna Ragher. "Marginal Accuracy of Castings Fabricated with Ringless Casting Investment System and Metal Ring Casting Investment System: A Comparative Study." Journal of Contemporary Dental Practice 17, no. 2 (2016): 165–70. http://dx.doi.org/10.5005/jp-journals-10024-1821.
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ABSTRACT Background The thermal expansion of the investment can be restricted by the metal casting ring because the thermal expansion of the ring is less than that of the investment. The ringless casting procedure is in use in clinical dentistry, though there is little scientific data to support its use in fixed partial dentures. In this study, marginal discrepancy of castings produced with the ringless casting technique and the conventional technique using the metal rings were compared. Materials and methods A total of 30 wax patterns were fabricated directly on a metal die. Optical stereomicroscope was used to measure the marginal discrepancy between the metal die and wax patterns. A total of 15 castings were invested using Bellavest T phosphate-bonded investment with the ringless technique and 15 were invested with the same investment with a metal ring; 30 castings were produced using a nickel-chromium ceramo-metal alloy. The internal surface of the castings was not modified and seated with finger pressure. The vertical marginal discrepancy was measured using an optical stereomicroscope at a magnification of 100×. The data obtained were statistically analyzed using students t-test (paired t-test and unpaired t-test). Results The castings of the ringless technique provided less vertical marginal discrepancy (240.56 ± 45.81μ) than the castings produced with the conventional metal ring technique (281.98 ± 53.05μ). The difference was statistically significant. Conclusion The ringless casting technique had produced better marginal accuracy compared with conventional casting technique. Ringless casting system can be used routinely for clinical purpose. How to cite this article Kalavathi M, Sachin B, Prasanna BG, Shreeharsha TV, Praveen B, Ragher M. Marginal Accuracy of Castings Fabricated with Ringless Casting Investment System and Metal Ring Casting Investment System: A Comparative Study. J Contemp Dent Pract 2016;17(2):165-170.
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Prikhod’ko, O. G., V. B. Deev, E. S. Prusov, and A. I. Kutsenko. "Influence of thermophysical characteristics of alloy and mold material on castings solidification rate." Izvestiya. Ferrous Metallurgy 63, no. 5 (July 1, 2020): 327–34. http://dx.doi.org/10.17073/0368-0797-2020-5-327-334.
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Obtaining castings of given quality is the main task of foundry production. One of the stages of casting technology is solidification of melt in the mold. When studying the process of castings solidification, it is necessary to fully take into account all the features of heat transfer between casting and mold. Influence of various thermophysical parameters of alloy and mold material on casting formation is considered. In the analysis, original mathematical models were used to calculate the coefficient and time of complete solidification of castings in sand-clay and metal forms. These models take into account geometric parameters of casting, main thermophysical parameters of casting metal and mold material, heat transfer conditions at crystallization front, on casting-mold boundary and on the mold surface. Analysis of dependence of time and rate of castings solidification on thermophysical parameters (heat capacity, density, heat conductivity of casting material and mold, specific heat of metal crystallization) was carried out. Storage capacity and process of heat storage are quite fully characterized by the value of heat storage coefficient. This coefficient practically determines the rate of heat loss by the casting which plays a decisive role in its properties forming. Therefore, this parameter is selected for a comprehensive analysis of thermal processes occurring in casting and mold. The influence of thickness and thermal conductivity of chill paint layer on solidification of castings in metal molds is considered. The basic calculation formulas and initial data are presented. Calculations were carried out for castings of the following types: endless plate, endless cylinder, ball. The results of simulation of solidification process parameters are presented in graphic form. Using various alloys as an example, it has been shown by calculation that when changing composition and properties of mold material, it is possible to change time and speed of alloys solidification in a wide range. In this case, processes of forming the structure and properties of castings are controlled.
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Gawdzińska, K. "Quality Features of Metal Matrix Composite Castings." Archives of Metallurgy and Materials 58, no. 3 (September 1, 2013): 659–62. http://dx.doi.org/10.2478/amm-2013-0051.
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Abstract In this paper it is stated, that a set of quality features of metal matrix composite castings differs from the same set for castings of classic materials, although some features are common for both of these material groups. These features (pertaining to a set of quality characteristics of composite castings) have been named as specific, they have not been determined yet and a description of material quality should be performed (according to the qualitology) on a principle of description of quality characteristics of this product. Therefore, this set of features has been determined. It was proposed to add the following characteristics to the set of specific features of composite castings quality: matrix material, reinforcement material, binding between components and porosity of the composite casting. In this set a sub-set of quality characteristics of composite castings was also determined.
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Rvachev, V. L., T. I. Sheiko, V. Shapiro, and J. J. Uicker. "Implicit Function Modeling of Solidification in Metal Castings." Journal of Mechanical Design 119, no. 4 (December 1, 1997): 466–73. http://dx.doi.org/10.1115/1.2826391.
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Solidification of metal castings can be modeled by an implicit real-valued function whose behavior is determined by physical parameters prescribed on the boundary of a casting. We show how to construct such functions using theory of R-functions for two-dimensional castings represented by their boundaries. The parameterized form of the constructed functions is convenient for studying, controlling, and optimizing their behavior in terms of the physical parameters specified on the boundary of the casting. The proposed approach can also be used for modeling multiple cavities in a same sand mold, generalizes to three-dimensional castings, and is applicable to other physical phenomena that may be suitable for analysis based on empirical knowledge.
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Acimovic-Pavlovic, Zagorka, Milutin Djuricic, Sasa Drmanic, and Rade Djuricic. "The influence of the parameters of lost foam process on the quality of aluminum alloys castings." Chemical Industry 64, no. 2 (2010): 121–27. http://dx.doi.org/10.2298/hemind100301011a.
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This paper presents the research results of application of Lost foam process for aluminum alloys castings of a simple geometry. The process characteristic is that patterns and gating of moulds, made of polymers, stay in the mould till the liquid metal inflow. In contact with the liquid metal, pattern intensely and in relatively short time decomposes and evaporates, which is accompanied by casting crystallization. As a consequence of polymer pattern decomposition and evaporation a great quantity of liquid and gaseous products are produced, which is often the cause of different types of casting errors. This paper presents the results of a research with a special consideration given to detecting and analyzing the errors of castings. In most cases the cause of these errors are defects of polymer materials used for evaporable patterns production, as well as defects of materials for refractory coatings production for polymer patterns. The researches have shown that different types of coatings determine properties of the obtained castings. Also, the critical processing parameters (polymer pattern density, casting temperature, permeability of refractory coating and sand, construction of patterns and gating of moulds) significantly affect on castings quality. During the research a special consideration was given to control and optimization of these parameters with the goal of achieving applicable castings properties. The study of surface and internal error of castings was performed systematically in order to carry out preventive measures to avoid errors and minimize production costs. In order to achieve qualitative and profitable castings production by the method of Lost foam it is necessary to reach the balance in the system: evaporable polymer pattern - liquid metal - refractory coating - sandy cast in the phase of metal inflow, decomposition and evaporation of polymer pattern, formation and solidification of castings. By optimizing the processing parameters castings of required structural and mechanical characteristics could be achieved, casting defects characteristic for this process could be avoided with the result of the production costs saving. The presented results can be useful to define parameters of Lost foam process and its application in practice with objective to obtain castings with in advance specified quality.
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Mäsiar, H., L. Repka, P. Lipták, and O. Híreš. "Investigate the Possibility of Tekcast Methods Used for Casting Polymeric Resin Materials." Archives of Foundry Engineering 14, no. 2 (June 1, 2014): 119–22. http://dx.doi.org/10.2478/afe-2014-0049.
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Abstract Contribution gives an overview of knowledge about the method of centrifugal casting with orientate on Tekcast system. Company Tekcast Industries has developed a device for centrifugal casting, extending the area of production of castings or prototyping of metal or plastic. Materials suitable for the centrifugal casting with flexible operating parameters may include non-ferrous metal alloy based on zinc or aluminum or non-metallic materials such as polyester resins, polyurethane resins, epoxy resins, waxes and the like. The casting process is particularly suitable for a wide range of commercial castings and decorative objects.
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Hojjat Majidi, Seyyed, Christoph Beckermann, Jakob Fainberg, Wilfried Schäfer, and Mathias Bodenburg. "Modelling Approach and Challenges in Simulating Dross Formation in Ductile Iron Castings." Materials Science Forum 925 (June 2018): 419–26. http://dx.doi.org/10.4028/www.scientific.net/msf.925.419.
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Dross is one of the most challenging quality issues in high integrity ductile iron castings. The formation of dross is linked to the applied metallurgy, metal treatment, process control and gating/rigging design. One of the primary concerns in this regard is entrainment of air into the melt during filling of the casting. Today, avoiding and controlling dross relies on the practical experience and process know-how of foundry experts. A quantitative understanding of the formation mechanisms or the prediction of final amounts and locations of dross in castings is not available. In this paper a computational model is developed for predicting the formation, motion and final location of dross inclusions during pouring of ductile iron castings. The focus is on the important mechanism of dross generation due to air entrainment during filling of the mold. The model predicts the local air entrainment rate as a function of the turbulent kinetic energy of the liquid metal and the normal velocity gradient of the metal at the liquid metal-air interface. The dross inclusions resulting from the exposure to the entrained air are transported with the melt flow under the combined influences of drag and buoyancy, and captured by the solidifying casting structure. The model is implemented in a commercial casting simulation software code. Ductile iron casting experiments are conducted to validate the model using castings having a variety of gating systems, section thicknesses, and surface orientations. Dross is measured by serial sectioning of the solidified castings. Good agreement between measured and predicted dross amounts and locations is obtained. The results reveal how gating system design affects dross formation. Clean ductile iron castings can be obtained by minimizing air entrainment during pouring. The present model allows foundries to evaluate different gating designs and pouring parameters before the first casting is poured. The paper also discusses open issues and practical challenges in quantifying the amounts of dross as a function of the entire processing route of a casting.
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Patil, Abhijit, Kishan Singh, Sukant Sahoo, Suraj Suvarna, Prince Kumar, and Anupam Singh. "Comparative assessment of marginal accuracy of grade II titanium and Ni-Cr alloy before and after ceramic firing: An in vitro study." European Journal of Dentistry 07, no. 03 (July 2013): 272–77. http://dx.doi.org/10.4103/1305-7456.115409.
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ABSTRACT Objective: The aims of the study are to assess the marginal accuracy of base metal and titanium alloy casting and to evaluate the effect of repeated ceramic firing on the marginal accuracy of base metal and titanium alloy castings. Materials and Methods: Twenty metal copings were fabricated with each casting material. Specimens were divided into 4 groups of 10 each representing base metal alloys castings without (Group A) and with metal shoulder margin (Group B), titanium castings without (Group C) and with metal shoulder margin (Group D). The measurement of fit of the metal copings was carried out before the ceramic firing at four different points and the same was followed after porcelain build-up. Results: Significant difference was found when Ni-Cr alloy samples were compared with Grade II titanium samples both before and after ceramic firings. The titanium castings with metal shoulder margin showed highest microgap among all the materials tested. Conclusions: Based on the results that were found and within the limitations of the study design, it can be concluded that there is marginal discrepancy in the copings made from Ni-Cr and Grade II titanium. This marginal discrepancy increased after ceramic firing cycles for both Ni-Cr and Grade II titanium. The comparative statistical analysis for copings with metal-collar showed maximum discrepancy for Group D. The comparative statistical analysis for copings without metal-collar showed maximum discrepancy for Group C.
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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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Chernyshov, E. A., I. V. Baev, and A. D. Romanov. "Mechanical properties and structure of castings at different ladle processing of liquid and crystalizing steel." Izvestiya. Ferrous Metallurgy 63, no. 8 (October 8, 2020): 644–50. http://dx.doi.org/10.17073/0368-0797-2020-8-644-650.
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The paper presents studies on the effect of external influences when pouring-in high-strength alloyed steel into thin-walled metalshell molds with external cooling and into the same molds with suspension pouring-in (complex effect on hardened casting). Prerequisites for the selection of these technologies are considered. As control metal, we have investigated the casting received in volume liquid glass form. Macrostructure, cross-sectional view and mechanical properties of the metal at normal (+20 °C) and raised (+350 °C) temperatures were studied. The most dense and uniform structure and cross-sectional view were received in casting at complex influence. It was established that the main advantage of the offered technologies is increase in uniformity of mechanical properties on the section and height of castings, especially of plastic properties and impact strength. The anisotropy of properties on the section and height of pilot castings is much less, than in control casting. As a result of the studies, it was found that the external and complex effect on the forming casting allows one to affect the macrostructure and to improve the mechanical properties of castings at various test temperatures of the samples. In castings obtained in a metal-shell form with forced cooling, there is no noticeable difference in the mechanical properties both in height and in cross section of the casting. Moreover, the strength properties are by an average 100 MPa higher than that of the control casting, while maintaining high values of ductility and toughness.
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Georgiev, Georgi Evt, Sasho Popov, Valentin Manolov, Rositsa Dimitrova, and Pavel Kuzmanov. "Heat Transfer Process Computer Simulation and Microstructure Prediction During Crystallization of Metal Alloys." Journal of Theoretical and Applied Mechanics 43, no. 1 (March 1, 2013): 71–78. http://dx.doi.org/10.2478/jtam-2013-0007.
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Abstract Processes of crystallization during casting formation from aluminum alloys, steel and cast iron have been studied using 3-D com- puter simulation. Temperature fields of castings have been obtained and the microstructure distribution of these castings has been predicted. A comparison between numerical results and experimental measurement has been performed. It is proved, that the proposed approach is suitable for investigation and analysis of casting technologies.
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Eperješi, Š., M. Matvija, ľ. Eperješi, and M. Vojtko. "Evaluation of Cracking Causes of AlSi5Cu3 Alloy Castings." Archives of Metallurgy and Materials 59, no. 3 (October 28, 2014): 1089–92. http://dx.doi.org/10.2478/amm-2014-0187.
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Abstract Recently, the castings made from aluminum-silicon alloys by pressure die casting are increasingly used in the automotive industry. In practice, on these castings are high demands, mainly demands on quality of their structure, operating life and safety ensuring of their utilization. The AlSi5Cu3 alloy castings are widely used for production of car components. After the prescribed tests, the cracks and low mechanical properties have been identified for several castings of this alloy, which were produced by low pressure casting into a metal mould and subsequent they were heat treated. Therefore, analyses of the castings were realized to determine the causes of these defects. Evaluation of structure of the AlSi5Cu3 alloy and causes of failure were the subjects of investigation presented in this article.
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Gašpár, Štefan, Ján Majerník, and Jan Kolínský. "Analysis of Causes of Porosity Change of Castings under the Influence of Variable Biscuit Height in the Filling Chamber." Materials 14, no. 22 (November 12, 2021): 6827. http://dx.doi.org/10.3390/ma14226827.
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Quality properties of castings produced in a die casting process correlate with porosity that is conditioned by a number of factors, which range from input melt quality to setup of technological factors of the die casting, and through structural design of the gating system. One of the primary parameters conditioning the inner soundness of the casting is the liquid metal dose per single operation of die casting. This paper examines the issue of metal dose. The experiments are performed with casting a gate system of an electromotor flange. The gating system examined was die cast with a variable volume of metal dose per single operation. The metal dose was adjusted to reach the height of a biscuit of 10, 20, and 30 mm. The examination of the inner homogeneity of the castings of the individual variants of gating systems with variable height of the biscuit proved that decreasing biscuit height results in an increase of porosity share in the casting volume. The programme MagmaSoft 5.4 revealed the main causes of changes in porosity share. The simulations detected that the change in biscuit height and volume of liquid metal directly influence thermal conditions of the melt in the filling chamber, and in the mould by means of the period in which the holding pressure action is influenced. Simultaneously, the melt flow mode in the sprues and gas entrapment in the melt volume are affected as well. Correlation of the factors consequently influences the final porosity of castings.
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Pasko, Ján, Stefan Gaspar, and Juraj Ružbarský. "Die Casting Defects of Castings from Silumin." Applied Mechanics and Materials 510 (February 2014): 91–96. http://dx.doi.org/10.4028/www.scientific.net/amm.510.91.
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The production of die castings cast into a metal mold has in recent years achieved an expansive growth in the volume as well as the range of production and that is particularly in aviation and automobile industry. A primary criterion for achieving reliability, efficiency and quality of production is to ensure minimization of the castings defects occurrence. For this reason it is necessary to describe the type, scope and frequency of die castings defects and to define the cause of their occurrence.
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Fecko, D., I. Vasková, Ľ. Eperješi, and M. Závodný. "Usage of Connor Inlets to Eliminate Shrinkage." Archives of Foundry Engineering 12, no. 3 (September 1, 2012): 25–28. http://dx.doi.org/10.2478/v10266-012-0076-0.
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Abstract The demand for castings of high quality and sound work is nowadays very high. The production of sound castings without foundry errors is the big issue in modern foundries. Foundry simulation software can do a lot to help improve the disposition of castings, gating system and feeder system, and assure good filling and solidification conditions, and also produce sound casting without the need of the old method of "try and error". One can easily change a lot of parameters for filling and solidification, and create the best proposal for production. Connor inlets have two functions. One is that it serves as an ingate, through which molten metal passes and comes into the mould cavity. The second function is that it serves as a feeder and substitutes the metal contracted during solidification and cooling of the castings. It can also save quite a lot of metal in comparison to classic feeders.
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Molnár, Dániel, Ádám Kiss, and Csaba Majoros. "Casting Issues of Thick-Walled High Pressure Die Castings." International Journal of Engineering and Management Sciences 5, no. 2 (April 15, 2020): 159–66. http://dx.doi.org/10.21791/ijems.2020.2.20.
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Die casting is a manufacturing process for producing accurately dimensioned, sharply defined, smooth or textured surface metal parts. It is accomplished by injecting liquid metal at fast velocity and under high pressure into reusable steel dies. Compared to other casting processes, die casting is at the top end of both velocity and pressure. The high velocity translates into a very turbulent flow condition. The process is often described as the shortest distance between raw material and the finished product.
Pre-fill is a process technique that is the result of significantly delaying the start of fast shot beyond the “metal at the gate” position. It can be stated as a percentage of cavity fill or as a distance beyond metal at the gate.
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Nadolski, M., Z. Konopka, M. Łągiewka, and A. Zyska. "The Influence of the Method of Mould Filling on the Quality of Castings Made of EN AC-44000 or EN AC-46200 Alloy." Archives of Foundry Engineering 14, no. 4 (December 1, 2014): 73–76. http://dx.doi.org/10.2478/afe-2014-0089.
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Abstract The performed examinations concerning the process of filling the plaster ceramic moulds with aluminium alloys allowed to assess the influence of various methods of introducing the metal into the mould cavity on the macro- and microstructure of the obtained experimental castings. The comparison was performed for castings with graded wall thickness made either of EN AC-44000 alloy or of EN AC-46000 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. It was found that the silicon crystals grow in size with an increase in wall thickness due to the slower cooling and solidification of castings
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Wang, Yingli, and Fengxian Wang. "Key Analysis of Design and Numerical Simulation for Aluminum Alloy Impeller Low-pressure Casting Mold." Journal of Physics: Conference Series 2338, no. 1 (September 1, 2022): 012070. http://dx.doi.org/10.1088/1742-6596/2338/1/012070.
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Abstract It is of great practical value to complete the low-pressure casting of aluminum alloy impeller in the current development of low-pressure casting process. In the research, it is necessary to focus on factory realization and use low-pressure casting to produce aluminum alloy impellers, so that impeller castings with compact structure and meeting performance requirements can be obtained. Compared with other casting methods, low-pressure casting itself, as a precision casting method, can be cast on the metal solution with lower pressure in the application process. The castings can be filled and solidified under certain pressure, and the castings with compact structure can be obtained. In the research, Pro / Engineer is used to design the low-pressure casting mold for aluminum alloy impeller, and MAGMASOFT is used to carry out the filling and solidification process of aluminum alloy impeller. Through numerical simulation, we can accurately predict the defects of impeller castings, and optimize the mold scheme and pressure-time parameters according to the prediction results.
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Doroshenko, V. S., and P. B. Kaliuzhnyi. "Isothermal hardening of iron-carbon alloys combined with their casting." Metaloznavstvo ta obrobka metalìv 30, no. 1 (March 29, 2024): 47–59. http://dx.doi.org/10.15407/mom2024.01.047.
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Isothermal hardening (Austempering) of iron-based alloys with medium and high carbon content, which creates a metallic structure called bainite, is used to increase the strength and impact toughness of the metal. The parts are heated to a temperature approximately 200-300 °C below the solidification temperature of the metal, then cooled (hardened) fairly quickly to the temperature of the beginning of the bainite transformation, avoiding the martensitic transformation, and kept for a time sufficient to obtain the given bainite microstructure. IG is particularly advantageous for castings from high-strength cast iron (HC), adding to the high foundry performance of the growth of the mechanical characteristics of this alloy to the level of steel strength at a lower cost, density and energy consumption of HC casting compared to steel. The article examines methods of heat treatment of castings removed in a hot austenitic state from a sand mold, as a type of heat treatment of iron-carbon alloys combined with their casting. For this, casting according to gasification models was used, in which, due to the high fluidity of the dry sand of the casting mold, it is not difficult to remove hot castings from the mold for tempering. A number of IG methods previously patented by the FTIMS Institute of the National Academy of Sciences of the Russian Academy of Sciences have been supplemented by a new method of such hardening in a dosed amount of water, taking into account the effect of its film boiling. The new method includes the calculation of the optimal mass of quenching liquid - water with the aim of heating this mass of water to its boiling point at the time of cooling of the casting to the given temperature of the bainite transformation of the metal. The method saves the quenching liquid, simplifies the control of the duration of cooling, during which it allows the transportation of castings between the foundry and heat-treatment sections, which, in general, saves time, energy resources and the area of the workshop for obtaining heat-treated castings. Keywords: isothermal hardening, heat treatment, castings, austenite, lost foam casting.
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Binczyk, F., J. Cwajna, P. Gradoń, M. Mańka, and R. Findziński. "Surface Modification of Cored, Thin Walled Castings of Nickel Superalloy IN-713C." Archives of Foundry Engineering 15, no. 3 (September 1, 2015): 17–20. http://dx.doi.org/10.1515/afe-2015-0051.
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Abstract In current casting technology of cored, thin walled castings, the modifying coating is applied on the surface of wax pattern and, after the removal of the wax, is transferred to inner mould surface. This way the modification leading to grain refinement occur on the surface of the casting. In thin walled castings the modification effect can also be seen on the other (external) side of the casting. Proper reproduction of details in thin walled castings require high pouring temperature which intensify the chemical reactions on the mould – molten metal interface. This may lead to degradation of the surface of the castings. The core modification process is thought to circumvent this problem. The modifying coating is applied to the surface of the core. The degradation of internal surface of the casting is less relevant. The most important factor in this technology is “trough” modification – obtaining fine grained structure on the surface opposite to the surface reproduced by the core.
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Doroshenko, V. S., and P. B. Kaliuzhnyi. "Prevention of surface defects on the internal cavities of casing iron castings." Fundamental and applied problems of ferrous metallurgy 36 (2022): 487–98. http://dx.doi.org/10.52150/2522-9117-2022-36-487-498.
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The insufficiently high quality of the surface of metal castings, which are made in sand molds, is due to the formation of various surface defects, of which galling is the most common. Cleaning castings from scorch leads to additional costs of material and labor resources, which can reach 40-60% of the total labor intensity of production. The process of increasing the strength of the non-stick coating of casting molds and rods can be implemented by optimizing its composition. According to the result of the analysis of thermochemical reactions at the contact interface "melt - mold" in the process of heat exchange between the casting and the casting mold and related physical processes, as well as hydrodynamic processes of interaction in the contact zone, in particular, specific for graphitized cast iron, in order to prevent surface defects on the internal cavities of body cast iron castings, after experimental and industrial work, non-stick coatings of increased resistance were developed and applied in foundry production for sand molds and rods. Coating compositions were completed according to the concept of partially directing the energy of the high-temperature exposure of the metal to chemical transformations in the non-stick coating and the contact zone of the sand mold with the formation of compounds that would contribute to the sintering of the particles of the surface layer of the mold at the temperature of its heating from the contacting metal. This served as a means of preventing cracks in such a layer and avoiding cracks and mechanical burning on the surface of castings. A method of reducing the metal pressure from the pre-shrinkage expansion of graphitized cast irons during its action on the surface of the walls of the casting cavities by the timely partial weakening of the vacuumed casting mold without disturbing the given geometry of the casting when applying the method of casting according to gasifying patterns has also been developed.
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Balakrishnan, Dhanasekar, Vinu T. George, Tanuka Dutta, and Aparna Ichalangod Narayan. "An in vitro Comparative Study to evaluate the Marginal Fit of Castings using Ring and Ringless Casting Techniques with varying Sprue Diameter." World Journal of Dentistry 8, no. 2 (2017): 109–13. http://dx.doi.org/10.5005/jp-journals-10015-1422.
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ABSTRACT Introduction The ultimate success of fixed prosthesis is to pay meticulous attention to the detailed production of the missing tooth structure. Such an accurate replication is technically demanding. Hence, the aim of the study was to evaluate the accuracy of marginal fit of castings with varying sprue diameter and using ring and ringless techniques. Materials and methods Forty standardized wax copings were fabricated on a stainless steel die and divided into two groups. The first group was cast using the metal ring investment technique; the second group was cast using the ringless investment technique. Both the groups were further divided into two groups, each based on the diameter of the sprue (groups I and III: 4.5 mm and groups II and IV: 2.5 mm). The vertical marginal gap was measured at three sites per specimen, using a digital optical microscope at ×100 magnification. The results were analyzed using two-way analysis of variance and independent t-test to determine statistical significance. Results The vertical marginal gaps of castings fabricated using the ringless technique (0.145 ± 0.072 mm) were significantly less (p < 0.001) than those castings fabricated using the conventional metal ring technique (0.264 ± 0.100 mm); however, the vertical marginal gaps of the 2.5 mm sprue diameter (0.199 ± 0.092 mm) and 4.5 mm sprue diameter (0.211 ± 0.118 mm) castings were not statistically significant (p > 0.05). There was also statistically significant interaction (p < 0.001) between group IIA (0.120 ± 0.038 mm) and group IA (0.302 ± 0.098 mm), which was analyzed using the independent t-test. Conclusion It can be concluded that the ringless casting technique in comparison to metal ring technique produces metal castings of better marginal adaptation. Furthermore, the sprue diameter had significant difference wherein the 4.5 mm diameter produced the least vertical discrepancies in the ringless casting technique and 2.5 mm produced lesser vertical discrepancies in the metal ring. Clinical significance One of the key factors that decides the success of a metal-ceramic restoration is the marginal fit. The accurate fit of the restoration greatly minimizes the plaque accumulation, offers good mechanical properties, and reduces micro-leakage and development of secondary caries. The techniques of casting procedure and sprue diameter can have an influence on the outcome. Hence, the current research was undertaken to study the influence of these factors on marginal fit. How to cite this article Dutta T, George VT, Balakrishnan D, Narayan AI. An in vitro Comparative Study to evaluate the Marginal Fit of Castings using Ring and Ringless Casting Techniques with Varying Sprue Diameter. World J Dent 2017;8(2):109-113.
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Suranuntchai, Surasak, and Ekkachai Kittikhewtraweeserd. "Analysis of Horizontal Squeeze Casting Process for Pipe Oil Part." Advanced Materials Research 482-484 (February 2012): 154–58. http://dx.doi.org/10.4028/www.scientific.net/amr.482-484.154.
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To achieve the laminar flow filling pattern in squeeze casting processes, many literatures [1-4] have reported that ideal velocity of liquid metal passing through the ingate should be between 0.1 – 0.5 m/sec. John Campbell [1] reported that liquid metal front speed velocity should be 0.4 m/sec in order to eliminate the gas porosity inside the casting. However, such slow speed requires the higher temperature of liquid metal and die. This results in not only the longer cycle time but also a coarser microstructure of the casting. In addition, the sample castings used in the literature are simple form castings which do not reflect the real castings used in daily life. In this study, the indirect squeeze casting processes is adopted to cast a motorcycle’s component originally produced by a high pressure die casting process. Based on shape and dimensions of the casting to get the real casting out for the mass production, melt’s speed must be higher than the level reported by the literatures (around 1 m/sec). As a result, a fully laminar flow may not be achievable. This is confirmed by the primary study of the process parameters and tooling design using the casting process simulation. However, by clinging on the two principles of the squeeze casting processes; (1) minimizing the amount of entrapped air by slowly fill the cavity and (2) reducing the amount of solidification shrinkage by pressurized solidification; the casting from two processes will be casted in order to compared the micro-structure and mechanical properties.
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Kordas, P. "Influence of the conditions of casting and heat treatment on the structure and mechanical properties of the AlMg10 alloy." Journal of Achievements in Materials and Manufacturing Engineering 1, no. 83 (July 1, 2017): 26–32. http://dx.doi.org/10.5604/01.3001.0010.5137.
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Purpose: Assessment of the possibilities of shaping the structure and improvement of mechanical properties of casting from AlMg10 alloy through a selection of casting technology and precipitation hardening. Design/methodology/approach: the work evaluated the impact of casting and heat treatment technology on the mechanical properties and structure of AlMg10 alloy castings. The tests were performed on 200 mm × 100 mm × 25 mm plate castings produced by gravity casting methods for sand and metal moulds and by a liquid state press moulding technology. Castings made with these technologies solidify in substantially different heat- evaporation conditions and exhibit varying degrees of primary structure fragmentation. Metallographic and strength tests were performed on raw castings and after heat treatment. Findings: The changes in the morphology and size of primary crystals and the dispersion of the reinforcing phase according to the casting solidification rate and the precipitation hardening treatment were analyzed. Solidifying castings in the form of sand show a globular structure, whereas in die and press castings, a typically dendritic structure occurs, with the dendritic crystals in pressed castings being much smaller in size than the die castings. In castings which were not heat-treated, the reinforcing phase of Al3Mg2 occurs in interdendritic spaces, and its dispersion increases with the rate of cooling. After supersaturation and ageing treatments, the phase α has a grain structure in all samples. The largest dispersion of reinforcing molecules is characterized by press castings. In a raw state, the highest mechanical properties are shown by castings made in the form of sand and the method of pressing in a liquid state. Heat treatment of AlMg10 alloy castings significantly influences the increase of mechanical indexes in all castings investigated. The highest features of Rm are approx. 330 MPa and A5 above 10% is obtained in castings made by the press method. Research limitations/implications: Particular attention should be paid to the avoidance of the effects of slag inclusion, shrinkage and magnesium oxidation during casting of AlMg10 alloys. In die castings of a plate type, due to own stresses, a significant decrease in mechanical properties occurs. Practical implications: The most advantageous mechanical properties of AlMg10 alloy castings are obtained by using liquid-state pressing technology. In addition, this technology makes it possible to produce thin-walled castings of high dimensional accuracy, high air- tightness, fine grain structure, lack of surface defects and low roughness. Originality/value: The paper presents the possibility of improving the mechanical properties of AlMg10 castings by applying heat treatment. It has been proven that the casting method has a significant effect on the mechanical properties of the castings.
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Won, Chun-Soo, Jae Pil Jung, Kwang-Sik Won, and Ashutosh Sharma. "Technological Insights into the Evolution of Bronze Bell Metal Casting on the Korean Peninsula." Metals 12, no. 11 (October 22, 2022): 1776. http://dx.doi.org/10.3390/met12111776.
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Bronze cast bells have been designed and developed for hundreds of years, with the worldwide spread of several faiths and religions such as Buddhism, Catholicism, and Protestantism. The exceptional ringtones of bronze bell metals have scientific healing and cultural importance. In this review article, we highlight the evolution of bronze bell metal over the decades, its composition, and the complex fabrication technologies used to date. Furthermore, we overview ancient and modern casting alloy technology, especially bronze bell castings in Asia. The bell shape, materials, and alloy casting technology have undergone dramatic change over the years. For comparison, we include different bronze cast bells and their characteristics produced from the Middle Ages to the present times. Based on the data obtained from the bell casting technology surrounding the Korean Peninsula, the major trends in the evolution of bronze bell castings and long-standing traditions of mold materials and alloys are described. In the present review, the effects of different elements on bell materials are qualitatively overviewed, with an assessment of the material and casting properties, service life, and bell sound. We also highlight the challenges of conventional bronze casting and possible solutions for future investment castings and rapid prototyping of bronze bells.
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Wei, Bowen, and Weixin Gao. "Image processing of Casting defects based on Convolutional neural network." Journal of Physics: Conference Series 2137, no. 1 (December 1, 2021): 012059. http://dx.doi.org/10.1088/1742-6596/2137/1/012059.
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Abstract At present, there are numerous losses caused by corrosion cracking of metal castings in engineering in China. In order to detect the possible defects of metal castings in engineering, the laser ultrasonic vision inspection technology is used to image the castings, and then the identification efficiency is low. In order to process these images efficiently and quickly, convolutional neural network image processing technology is introduced. According to the actual needs, a convolutional neural network architecture is designed to recognize images, and whether the architecture meets the requirements is verified. Experimental results show that the performance of the architecture meets the design requirements. Under the same conditions, this structure provides a solution for casting defect detection combined with artificial intelligence.
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Gileva, Kseniya A. "FERDINAND BARBEDIENNE’S BRONZE FOUNDRY PRODUCTS AND URAL MEAL CASTING ART. ON THE ATRIBUTION OF URAL CAST-IRON ARTWORKS." Architecton: Proceedings of Higher Education, no. 3(71) (September 29, 2020): 22. http://dx.doi.org/10.47055/1990-4126-2020-3(71)-22.
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The study discusses the attribution of several Ural cast-iron artworks. The authors of the model range of metal castings from Kasli and Kusa factories are still the least researched in Russian art history and, thus, the study appears to be very timely. The article considers connections between the model range of the Urals plants and the famous French bronze foundry of Ferdinand Barbedienne. Castings available on the antiques market and in Russian museum collections are analyzed comparatively. New names of authors of Ural metal casting models are introduced into scholarship.
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Maekawa, Tatsuya, Mitsuaki Furui, Susumu Ikeno, Tomoyasu Yamaguchi, and Seiji Saikawa. "Microstructure Observation of AM60 Magnesium Alloy Solidified by Rapidly Quench." Advanced Materials Research 409 (November 2011): 339–42. http://dx.doi.org/10.4028/www.scientific.net/amr.409.339.
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In solidification theory, with a slow cooling rate such as sand mold casting, it is easy to segregate the solute aluminum near the grain boundary of primary α-Mg phase under the solidification in Mg-Al system alloys. Thus, volume fraction of none-equilibrium crystallized β-Mg17Al12 phase showed the higher value compared with metal mold casting with faster cooling rate. However, in our microstructure observation results, the volume fraction of β phase in permanent mold castings was larger than that of sand mold castings. In the present study, these contradictory behavior was investigated by observation of as-solidified microstructure obtained from rapid cooling castings at the just below the solidus temperature of 723, 773 and 823K.
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Lu, Hong Xing, Qiang Zhu, Da Quan Li, and Fan Zhang. "Floating Behavior of Entrapped Gas in Semi-Solid Metal." Materials Science Forum 898 (June 2017): 1254–60. http://dx.doi.org/10.4028/www.scientific.net/msf.898.1254.
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Semi-solid die casting technology has great advantages at defects control and has been successfully used to produce high quality aluminum alloy components for several years. In this process, semi-solid metal with high apparent viscosity and low plunger velocity are used to avoid surface turbulence which is the main source of entrapped gas in conventional die casting processes. But, entrapped gas still has other sources, such as melting, pouring, surface flooding and confluence weld. Solution heat treatment is always used to strengthen semi-solid die castings. The entrapped gas leads to blister defects, which directly decreases the acceptance rate of semi-solid die castings. So, the entrapped gas is still a serious issue in semi-solid die casting process. We studied the floating behavior of entrapped gas bubble in semi-solid metal. Two floating models were established for gas bubbles with different sizes. These models were used to analyze the possibility of entrapped gas escaping from semi-solid metal in casting practice. The results showed that entrapped gas from feed billet could not escape from the semi-solid metal in the casting process of impeller, which was proved by experiment results. These results emphasized the importance of clean melt and semi-solid metal. Some advices were given at last for avoiding or removing the entrapped gas in semi-solid die casting process.
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Gaspar, Stefan, Jan Pasko, and Slavko Pavlenko. "Research on the Impact of Increase Pressure on the Homogeneity of the Cast in Die Casting Technology." Advanced Materials Research 1091 (February 2015): 77–82. http://dx.doi.org/10.4028/www.scientific.net/amr.1091.77.
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The production of die castings cast into a metal mold has in recent years achieved an expansive growth in the volume as well as the range of production and that is particularly in aviation and automobile industry. In the process of die casting the final quality of a cast is influenced by a great number of factors. The main factors of die casting are: pressing velocity, increase pressure, the melt temperature and the mold temperature. A primary criterion for achieving reliability, efficiency and quality of production is to ensure minimization of the castings defects occurrence in castings correct setting technological factors of die casting. The presented paper deals with the experimental assessment of the impact of increase pressure on the mechanical properties and homogeneity of a die cast.
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Gaspar, Stefan, and Jan Pasko. "Homogeneity of Aluminum Castings and Dependency on Increasing Pressure." Key Engineering Materials 669 (October 2015): 134–41. http://dx.doi.org/10.4028/www.scientific.net/kem.669.134.
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The production of die castings cast into a metal mold has in recent years achieved an expansive growth in the volume as well as the range of production and that is particularly in aviation and automobile industry. In the process of die casting the final quality of a cast is influenced by a great number of factors. The main factors of die casting are: pressing velocity, increase pressure, the melt temperature and the mold temperature. A primary criterion for achieving reliability, efficiency and quality of production is to ensure minimization of the castings defects occurrence in castings correct setting technological factors of die casting. The presented paper deals with the experimental assessment of the impact of increase pressure on the mechanical properties and homogeneity of a die cast.
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Korchmit, Anton Viktorovich, Nikita V. Martyushev, and Yuriy Yu Drozdov. "Casting Quality Enhancement of Bushings Made of Foundry Aluminium Bronzes." Key Engineering Materials 685 (February 2016): 459–62. http://dx.doi.org/10.4028/www.scientific.net/kem.685.459.
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The paper is devoted to the establishment of the technology of castings manufacture out of multicomponent aluminium bronzes for oil and gas producing equipment. Aluminium bronze containing iron has been chosen as a material for casting manufacture. Founding into sand mixtures has been chosen as a manufacturing method. It has been shown that this type of founding allows obtaining the castings with minimal subsequent treatment and high quality surface. The use of the coke furnace at metal melting allows obtaining the castings with high performance characteristics due to gas protection of the melt.
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Liu, Gang, Lin Liu, Guo Jun Zhang, and Jun Zhang. "Microstructure and Element Segregation of Ni-Base Superalloy Casting with Radiation and Liquid-Metal Cooling." Materials Science Forum 816 (April 2015): 608–12. http://dx.doi.org/10.4028/www.scientific.net/msf.816.608.
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A Re-containing single-crystal superalloy was processed with conventional radiation high rate solidification (HRS) and liquid-metal cooling (LMC) techniques, respectively. Compared with the HRS castings, LMC castings exhibited the greatly refined dendrite structures and lower segregation. At the withdrawal rate of 50 μm/s, the primary and secondary dendrite arm spacing of LMC casting was 103 and 19 μm, which were reduced by 60 % and 53 % compared to the counterpart of HRS castings. Moreover, higher withdrawal rates significantly shortened the characteristic diffusion distance and reduced the residual segregation of refractory elements after homogenization-solution treatments, which is beneficial for improving the local phase stability of Re-containing superalloys.
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Doroshenko, Volodymyr, and Alexander Yanchenko. "Combined method of foundry and thermal processes of manufacturing castings from iron-carbon alloys." Journal of Mechanical Engineering and Transport 19, no. 1 (July 12, 2024): 55–60. http://dx.doi.org/10.31649/2413-4503-2024-19-1-55-60.
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With the help of innovations at an industrial enterprise, it is possible to increase labor efficiency and reduce the resource intensity of production. The relevance of the development of the technology of metal casting in sand molds, as the most common casting process, is justified by the fact that up to 80 % of the tonnage of castings is produced in such molds, including special types of casting in molds from sand materials. 60-70 % of the equipment capacities, areas, and personnel of foundry shops are attributed to molding processes, including mixing and rod production. Pollution "due to the mold" can reach up to 80%. A significant potential for the development of foundry mold technology is the improvement of the processes of casting metal into molds made of loose sand without a binding component, in particular, according to the Lost Foam Casting Process (LFC). The authors present the concept of improving the processes of casting metal into molds made of loose sand by the method of dual application of molding materials and give examples of such application. The use of loose molding sand for rapid cooling of the casting, including heat treatment, is able to strengthen its metal and reduce the duration of cooling of the casting in the mold, which leads to an increase in the productivity of foundries without increasing the number of furnace equipment and loose mold filler. The applied method of isothermal hardening (austempering) from the hot state of castings from iron-carbon alloys excludes heating with exposure for austenization of castings, which reduces the cost, time and energy consumption of obtaining products with a strengthened bainite structure, which, in fact, corresponds to the concept of realizing internal reserves as a foundry sand mold, and cast metal. Some foundry enterprises of the Vinnytsia region also use LFC or have concluded contracts, planning to reconstruct their shops for this ecological and economically beneficial foundry technology.
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Dyja, R. "Numerical Analysis of Influence of the Mold Material on the Distribution of Shrinkage Cavities." Archives of Foundry Engineering 13, no. 1 (March 1, 2013): 15–18. http://dx.doi.org/10.2478/afe-2013-0003.
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Abstract Production of castings, like any other field of technology is aimed at providing high-quality product, free from defects. One of the main causes of defects in castings is the phenomenon of shrinkage of the casting. This phenomenon causes the formation of shrinkage cavities and porosity in the casting. The major preventive measure is supplementing a shortage of liquid metal. For supplement to be effective, it is necessary to use risers in proper shapes. Usually, the risers are selected on the basis of determination the place of formation of hot-spots in the castings. Although in these places the shrinkage defects are most likely to occur, shape and size of these defects are also affected by other factors. The article describes the original program setting out the shape and location of possible cavities in the casting. In the program is also taken into account the effect of temperature on the change in volume of liquid metal and the resultant differences in the shape and size of formed shrinkage cavities. The aim of the article is to describe the influence that have material properties of the mold on the simulation results.
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Togubu, Sukirman A., Bambang Tjiroso, and Ivan Junaidy Abd Karim. "Analisa Pengaruh Variasi Temperatur Tuang Pada Proses Pengecoran Alumunium Kaleng Bekas Terhadap Sifat Kekerasan Dan Struktur Mikro." Patria Artha Technological Journal 8, no. 1 (June 4, 2024): 26–29. http://dx.doi.org/10.33857/patj.v8i1.852.
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The purpose of this study is to determine the effect of casting temperature variations on the hardness and microstructure of used aluminium cans. The casting method used in this research is the Lost Foam Casting method with a cast temperature variation of 670°C, 700°C and 730°C. Vickers hardness testing was carried out to determine the effect of temperature variations on hardness, microstructure observations were made to see what phenomena occurred. The results show that the hardness value with the lowest temperature of 670°C has a higher average hardness value in the Vickers test compared to the high temperature of 730°C. This shows that the pouring temperature rate of metal castings is more effective in metal recycling at 670°C for the hardness value in the Vickers test. Porosity decreases with increasing pouring temperature, seen at 670°C with a microstructure magnification of 100x the porosity is rather round and large on the surface of the castings. While at a temperature of 730°C with a magnification of 100x microstructure, it can be seen that the porosity is getting smaller in the form of dots scattered on the surface of the castings.
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Konopka, Z., A. Chojnacki, A. Chojnacki, M. Łągiewka, and A. Zyska. "The Influence of Home Scrap on Porosity of MgAl9Zn1 Alloy Pressure Castings." Archives of Foundry Engineering 17, no. 1 (March 1, 2017): 99–102. http://dx.doi.org/10.1515/afe-2017-0018.
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Abstract The work presents the results of examinations concerning the influence of various amounts of home scrap additions on the porosity of castings made of MgAl9Zn1 alloy. The fraction of home scrap in the metal charge ranged from 0 to 100%. Castings were pressure cast by means of the hot-chamber pressure die casting machine under the industrial conditions in one of the domestic foundries. Additionally, for the purpose of comparison, the porosity of specimens cut out directly of the MgAl9Zn1 ingot alloy was also determined. The examinations consisted in the qualitative assessment of porosity by means of the optical microscopy and its quantitative determination by the method of weighting specimens in air and in water. It was found during the examination that the porosity of castings decreases with an increase in the home scrap fraction in the metal charge. The qualitative examinations confirmed the beneficial influence of the increased home scrap fraction on the porosity of castings. It was concluded that the reusing of home scrap in a foundry can be a good way of reduction of costs related to the production of pressure castings.
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Kovtunov, A. I., D. A. Semistenov, Yu Yu Khokhlov, and S. V. Myamin. "The research of the processes of formation of porous non-ferrous metals." Vektor nauki Tol'yattinskogo gosudarstvennogo universiteta, no. 2 (2021): 9–17. http://dx.doi.org/10.18323/2073-5073-2021-2-9-17.
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Foamed metals are promising materials with a unique combination of mechanical and operational properties: low specific gravity, low thermal conductivity, ability to absorb acoustic and electromagnetic vibrations, and the ability to deform under a constant load. Currently, the most used methods for producing foamed aluminum and foamed magnesium are methods based on mixing gas or porophore into molten aluminum and forming a porous structure during the solidification of the aluminum melt. An alternative to this technology is the formation of a porous structure through the use of soluble granules that pre-fill the mold and after impregnating the granules with molten metal and solidifying the castings, they are leached. The work aims to determine the influence of casting modes and the size of granules on the depth of impregnation of granular filling with metal melt during the formation of porous aluminum castings. The authors proposed the technique for calculating the depth of impregnation of granular filling when producing castings of porous non-ferrous metals based on the calculation of melt cooling when moving along the thin-walled channel. The calculations made it possible to determine the depth of impregnation and establish the allowable wall thickness of the casting of porous aluminum, depending on the size of the granules used, the speed of the melt in a form, the mold temperature, and the temperature of molten aluminum. The study identified that to increase the depth of impregnation and obtain porous aluminum castings with thinner walls, it is advisable to increase the diameter of the salt granules and not the temperature and hydrodynamic modes of casting. The authors carried out calculations and identified the influence of the casting regimes and the diameter of the granules on the depth of mold impregnation to obtain porous castings from promising magnesium alloys.
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Fracchia, Elisa, Federico Simone Gobber, Claudio Mus, Yuji Kobayashi, and Mario Rosso. "About Residual Stress State of Castings: The Case of HPDC Parts and Possible Advantages through Semi-Solid Processes." Solid State Phenomena 327 (January 10, 2022): 272–78. http://dx.doi.org/10.4028/www.scientific.net/ssp.327.272.
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Nowadays, one of the most crucial focus in the aluminium-foundry sector is the production of high-quality castings. Mainly, High-Pressure Die Casting (HPDC) is broadly adopted, since by this process is possible to realize aluminium castings with thin walls and high specific mechanical properties. On the other hand, this casting process may cause tensile states into the castings, namely residual stresses. Residual stresses may strongly affect the life of the product causing premature failure of the casting. Various methods can assess these tensile states, but the non-destructive X-Ray method is the most commonly adopted. Namely, in this work, the residual stress analysis has been performed through Sinto-Pulstec μ-X360s. Detailed measurements have been done on powertrain components realized in aluminium alloy EN AC 46000 through HPDC processes to understand and prevent dangerous residual stress state into the aluminium castings. Furthermore, a comparison with stresses induced by Rheocasting processes is underway. In fact, it is well known that Semi-Solid metal forming combines the advantages of casting and forging, solving safety and environmental problems and possibly even the residual stress state can be positively affected.
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Kumar, Vinod, and Amitesh Kumar. "Simulation of Cooling Rate of Gray Cast Iron Casting in a Sand Mold and its Experimental Validation." Materials Science Forum 710 (January 2012): 208–13. http://dx.doi.org/10.4028/www.scientific.net/msf.710.208.
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Estimation of cooling rates of gray cast iron casting in the sand mold and its dependency on design and process parameters is one of the keys for achieving best processing conditions to produce quality castings. The estimation of cooling rate involves modeling of fluid flow, heat transfer and solidification of molten metal inside the mold. Prediction of heat transfer has been carried out from filling of mold but the estimation of cooling rate has been carried out after complete filling of the mold. In the present work fluid flow, heat transfer and solidification of molten metal in a sand mold model has been developed on a Pro-Cast 2008 platform. A stepped bar pattern with different thickness has been fabricated to carry out the experiment. Stepped bar pattern has been selected because gray cast iron castings are thickness sensitive as well as different section of castings have different cooling rate. Cooling rates have been determined experimentally by measuring the Dendritic Arm Spacing (DAS) and Secondary Dendritic Arm Spacing (SDAS) from the microstructure of different steps. Results show that the morphology of graphite, dendritic arm spacing and secondary dendritic arm spacing as well as the interlamellar spacing of eutectic structure depend on the casting thickness. These decreases as the thickness of castings decrease because thinner section of casting has higher rate of cooling than the thicker section. The estimated cooling rate matched well with the experimentally measured cooling rate.
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Kagawa, Akio, Masayuki Mizumoto, and Takeshi Ohgai. "Solid Free-Form Fabrication of Metallic Components." Advanced Materials Research 15-17 (February 2006): 175–80. http://dx.doi.org/10.4028/www.scientific.net/amr.15-17.175.
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The influence of process parameters on shape stability and surface smoothness of cylindrical and rectangular castings produced by fused spinning deposition (FSD) method was investigated. The optimum conditions to control the shape and smoothness of side surface of the castings produced by the FSD method without water-cooling were limited to a narrow range of process parameters. The casting with a stable shape and a smooth side surface was obtained with the aid of water-cooling. The tensile strength of the castings produced by the FSD method was 1.4 times higher than those of the specimens cast into metal-mold and sand-mold, due to a finer equiaxed grain structure of the FSD castings. Employing the combination of the deposition patterns for tube and solid castings, some practical metallic components were fabricated by the FSD method.
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Li, Yue, Ziming Wang, Xiaobin Zhou, Hong Xiao, and Qiang Yue. "A review of electromagnetic stirring on solidification characteristics of molten metal in continuous casting." Metallurgical Research & Technology 121, no. 3 (2024): 312. http://dx.doi.org/10.1051/metal/2024029.
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The solidification of molten metal represents a pivotal phase in the preparation and shaping of metallic materials. Continuous casting, as a crucial juncture in the solidification of molten metal, occupies a position of paramount significance. Nevertheless, during the process of continuous casting, challenges emerge, including uneven temperature field distribution, non-uniform solidification microstructures, and the presence of impurities, leading to defects such as segregation and shrinkage in the castings. Researchers have devoted decades to addressing these issues, culminating in the discovery that the application of electromagnetic stirring during continuous casting can expedite the flow of molten metal, enhance solute diffusion, thereby achieving uniform temperature and flow field distributions, refining solidification microstructures, and ameliorating macrosegregation, among other benefits. This article provides an overview of the recent research achievements and advancements in the utilization of electromagnetic stirring during the continuous casting process. It primarily elucidates various stirring devices commonly employed in continuous casting and expounds upon the influence of electromagnetic stirring on solidification characteristics. And the current problems and future development trends in the application of electromagnetic stirring were discussed.
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Pagnano, Valéria Oliveira, Marina de Campos Esquivel, Mônica Barbosa Leal, Daniela Nair Borges Felipucci, and Osvaldo Luiz Bezzon. "Effect of casting atmosphere on the shear bond strength of a ceramic to Ni-Cr and Ni-Cr-Be alloys." Brazilian Dental Journal 20, no. 2 (2009): 138–42. http://dx.doi.org/10.1590/s0103-64402009000200009.
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The success of metal-ceramic restorations depends on an optimal bond between metal and ceramic. This study evaluated the effect of 3 casting atmospheres on the metal-ceramic bond strength (MCBS) of 2 Ni-Cr alloys, with beryllium (Fit Cast V) and without beryllium (Fit Cast SB). Sixty acrylic resin patterns (8 mm long and 5 mm diameter) were obtained using a fluorocarbon resin matrix. Wax was used to refine the surface of acrylic resin patterns that were invested and cast in an induction casting machine under normal, vacuum, and argon atmospheres at a temperature of 1340ºC. The castings were divested manually and airborne-particle abraded with 100-µm aluminum-oxide. Ten castings were obtained for each group. The IPS Classic V ceramic was applied (2 mm high and 5 mm diameter). The shear bond strength was tested in a mechanical testing machine with a crosshead speed of 2.0 mm/min. The MCBS data (MPa) were subjected to 2-way analysis of variance (α=0.05). There was no statistically significant difference (p>0.05) between the alloys or among the casting atmospheres. Within the limitations of this study, it may be concluded that the presence of beryllium and the casting atmosphere did not interfere in the MCBS of the evaluated metal-ceramic combinations
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Lysenko, T., V. Yasyukov, K. Kreitser, and E. Kozishkurt. "Obtaining Castings in Low-pressure Casting Using Multiple Metal Wires." Casting processes 140, no. 2 (June 1, 2020): 65–71. http://dx.doi.org/10.15407/plit2020.02.065.
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Kondratyuk, S. Ye, V. I. Veis, and Z. V. Parkhomchuk. "The effect of thermal treatment of the melt before crystallization on the structure and properties of castings." Archives of Materials Science and Engineering 1, no. 104 (June 1, 2020): 23–29. http://dx.doi.org/10.5604/01.3001.0014.3866.
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Purpose: The aim of the proposed research is to investigate the influence of temperature and duration of isothermal melt processing on structural characteristics of castings in connection with technological background of charge metal. Design/methodology/approach: Ferrous and non-ferrous alloys were obtained by remelting a charge with a dispersion-structured structure (which was ensured by highspeed crystallization). Remelting was carried out at different temperatures of overheating of the melt over the liquidus with different isothermal exposure at these temperatures. Experimental castings were crystallized under normal conditions. It was studied a change of structure formation and mechanical characteristics depending on the temperature and duration of thermal treatment of the melt before crystallization. Findings: It is established that isothermal treatment of the melt at the overheating of the liquid metal above a certain equilibrium temperature of the micro-inhomogeneous melt (Te) causes a gradual loss of hereditary characteristics of the original charge metal, increase of the chemical homogeneity of the melt and the formation of crystallization and formation a corresponding change in the mechanical properties of castings. Research limitations/implications: The results can be complemented by studies of the effect of thermal treatment in the temperature range of crystallization. Practical implications: The results can be used to select the optimal heat treatment during remelting and, accordingly, the mechanical properties of the resulting casting. Originality/value: The obtained results testify to the predominant influence of temperature on the dispersion of the cast structure of steels, given the duration of technological operations of preparation and casting of steels in the manufacture of castings in industrial conditions.
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Залюбовський, М. Г., І. В. Панасюк, and В. В. Малишев. "ЕКСПЕРИМЕНТАЛЬНЕ ВИЗНАЧЕННЯ ЕНЕРГІЇ НЕОБХІДНОЇ ДЛЯ ВІДДІЛЕННЯ МЕТАЛЕВИХ ДЕТАЛЕЙ ВІД ЛИВНИКІВ." Bulletin of the Kyiv National University of Technologies and Design. Technical Science Series 138, no. 5 (February 3, 2020): 17–25. http://dx.doi.org/10.30857/1813-6796.2019.5.2.
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Experimental determination of the energy and the number of impact interactions with the solid supporting surface of the castings of the «zipper» lock necessary to separate parts from the gate. Getting the corresponding calculated dependencies. Experimental modeling of impact interaction of metal parts of the “zipper” lock with the surface of the working capacity by falling castings of parts from different heights with their further collision with the supporting surface. Based on the conducted experimental study, mathematical dependences are obtained that allow one to evaluate the effect of changes in mechanical energy on the intensity of separation of metal parts of the lightning lock from the gate. In particular, it was found that with an increase in mechanical energy during the fall of castings, the intensity of separation of metal parts from gates increases significantly. The relationship between the kinetic energy needed to separate the parts of the castings of the “zipper” lock at the moment of collision with a solid surface and the total cross-sectional area of the gating system is established. The relationship between the number of shock interactions of castings of the “zipper” lock with a solid surface, necessary for separating parts, the interaction energy and the casting parameters, is determined. The obtained mathematical dependences for calculating the number of shock interactions of castings of the “zipper” lock necessary to separate all parts from the gate system of the corresponding type when falling from any chosen height. These dependencies can be used to carry out further research, in particular, to rationally determine the time spent on performing these technological operations.
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ZHU, Xiaoping, Chunlei ZHU, Baosen LIN, and Zidong WANG. "Research on the Impact Behavior of Molten Metal on the Mold Shell in Gravity Casting of Large Titanium alloy Castings." Research and Application of Materials Science 5, no. 1 (March 22, 2024): 17. http://dx.doi.org/10.33142/rams.v5i1.11759.
Full textAbstract:
The impact behavior of molten metal on the mold shell in gravity casting of large titanium alloy castings by investment precision castings was studied. The physical and mechanical models of the impact of molten metal on the mold shell during the pouring process were constructed using numerical simulation. The effects of molten metal pouring rate and pouring weight on the maximum impact force of the mold shell were studied. The research results indicated that during the entire pouring process, the impact force of the first molten metal contacting the mold shell was higher than subsequent molten metal. The maximum impact force increased with the increase of pouring rate and pouring weight. The total impact force of the molten metal on the mold shell was composed of the instantaneous impact force converted from instantaneous impulse and itself gravity. The instantaneous impact force of the molten metal that first impacts the mold shell was much greater than its own gravity, while the impact force of the molten metal at the end of pouring was much less than its own gravity. The maximum impact force on the mold shell of a large casting with a pouring weight of 800kg was about three times higher than that of a medium-sized casting with a pouring weight of 80kg.The difference in the total impact force on the mold shell between them mainly comes from the instantaneous impact force converted from instantaneous impulse.
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Doos, Qasim M., and Ihsan K. A. Al-Naimi. "INVESTIGATION OF PARAMETERS AFFECTING LOST FOAM CASTING." Journal of Engineering 15, no. 04 (December 1, 2009): 4241–57. http://dx.doi.org/10.31026/j.eng.2009.04.10.
Full textAbstract:
The lost-foam casting process using expanded polystyrene foam pattern allows more complex and detailed passages to be cast directly into the part. The advantages of the lost-foam casting process involve, forms complex internal and external shapes without cores, reduces part mass with near net-shape capability, eliminates parting lines, and reduces machining operation and costs, Complex shapes with various sizes castings were produced in this technique in the foundry of the State Company for Electrical Industrials to evaluate the process. Successful complete castings were made. Many experimental works were done to further complements about fluidity parameter dealing with lost-foam casting process. Empirical linear and non-linear formulas were obtained from those experimental works to find the minimum temperature for pouring molten metal. Aluminum alloys were the material of choice for this work, due to the best combination of mechanical properties and castability, but the performance requirements and manufacturability issues will drive the choice of a specific aluminum that was aluminum-silicon alloy, which were used in this work.The macroscopic properties of the alloy depend strongly on the microstructure. Therefore, photomicrographs of microstructures of various castings with different foam pattern densities were done and made comparisons with common sand castings. Mechanical tests were conducted on the castings which produced by the common sand casting and the lost-foam casting processes. These tests include tensile, hardness, and impact. Because of using the expandable polystyrene as a pattern that gave, more gasses in the cavity of the mold during casting, so the mechanical tests show some differences between the two processes.
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Jie, Wan Qi, Xin Lei Li, and Qi Tang Hao. "Counter-Gravity Casting Equipment and Technologies for Thin-Walled Al-Alloy Parts in Resin Sand Molds." Materials Science Forum 618-619 (April 2009): 585–89. http://dx.doi.org/10.4028/www.scientific.net/msf.618-619.585.
Full textAbstract:
A counter-gravity casting equipment (CGCE) has been developed, which is specially designed for the production of large-size thin-walled high-quality aluminum alloy parts with resin sand molds. In this equipment, molten metal will be pushed upward counter-gravity into the mold at predetermined rate by compressed air, and solidified at an increased pressure. The equipment uses assembled valve system developed ourselves, and has sensitive pressure-adjusting property. All of the casting parameters, including filling rate, pressure-exerting sequence, pressure hold time etc., can be closely controlled by a self-designed computer program. Up to 2 ton casting can be produced with the equipment. Compared to the castings produced under conventional gravity conditions, the castings under counter-gravity condition have generally high soundness, higher tensile strengths and ductility. The pinhole defects are also degraded obviously. The equipment and the technology have been widely adopted by several users in China for the production of large-size thin-walled aluminum alloy castings with high property requirements.