Instability of the Liquid Metal–Pattern Interface in the Lost Foam Casting of Aluminum Alloys

Griffiths, W.D.; Ainsworth, Mark

doi:10.1007/s11661-016-3461-3

Cited by 24 publications

(13 citation statements)

References 17 publications

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“…In this study, the e s values were in the range of 0.39-0.42, and the average was 0.4. Substituting these values into equation (12), P cal ′ can be modified as follows:…”

Section: Preliminary Sand Experimentmentioning

confidence: 99%

“…e gas pressure in the kinetic zone has a significant role in preventing the sand collapse in contact with the kinetic zone [11] and in reducing the instability of the interface at the tip of the melt. Increasing the instability of the melt tip interface adversely affects product quality [12]. However, if the gas pressure reduces the speed of the molten metal, the pouring duration is long and casting defects, such as a metal fold, can occur.…”

Section: Introductionmentioning

confidence: 99%

“…Because this gas pressure also prevents sand collapse, it should be maintained at a suitable level. e gas pressure of the kinetic zone can be predicted based on findings from previous studies [8,12]. e gas pressure depends on the cross-section of the sprue and ingate, the height of the pouring basin, the permeability of the sand, the density of the expandable polystyrene pattern, the pouring temperature, and the melting speed.…”

Section: Introductionmentioning

confidence: 99%

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Gas Pressure Effect on Sand Collapse in Kinetic Zone of Lost‐Foam Casting

Jeon

Lee²,

Choe

et al. 2020

Advances in Materials Science and Engineering

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Pressure of the kinetic zone is an essential factor for making defect-free castings in lost-foam casting process. The extremely high pressure causes many problems, such as reducing the melt velocity and inclusion of residual decomposition of the pattern in the castings, and very low pressure causes sand collapse. Therefore, the minimum gas pressure for preventing sand collapse is required. When the minimum gas pressure can be predicted, computer simulation becomes possible. Successful computer simulations can help reduce the number of trials and the lead time while designing new casting products. A preliminary sand experiment was conducted to predict the gas pressure and reduce the number of actual casting experiments. In this preliminary sand experiment, compressed air was used instead of gas in the kinetic zone. A new mathematical equation was proposed from the results of the preliminary sand experiment. The void ratio of the sand effect on the minimum gas pressure was included in the equation. An actual casting experiment was conducted by melting nodular cast iron to verify this equation. In the actual casting experiment, pressure of the kinetic zone in front of the metal tip was directly measured. The results obtained from the preliminary sand experiment and the actual casting experiment validated the equation.

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“…In this study, the e s values were in the range of 0.39-0.42, and the average was 0.4. Substituting these values into equation (12), P cal ′ can be modified as follows:…”

Section: Preliminary Sand Experimentmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Gas Pressure Effect on Sand Collapse in Kinetic Zone of Lost‐Foam Casting

Jeon

Lee²,

Choe

et al. 2020

Advances in Materials Science and Engineering

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“…The movement of the molten metal is correlated with the styles of the decomposition of the foam pattern. There are several physical mechanisms to decompose the foam pattern, which depend on different factors such as the kind of foam beads as well as the location of the gate where the metal enters the foam [31]. The foam decomposition is classified into three modes: contact mode, gap mode, and collapsed mode [15].…”

Section: Forward Problem Solutionmentioning

confidence: 99%

Application of Electrical Capacitance Tomography for Imaging Conductive Materials in Industrial Processes

et al. 2019

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This paper presents highly robust, novel approaches to solving the forward and inverse problems of an Electrical Capacitance Tomography (ECT) system for imaging conductive materials. ECT is one of the standard tomography techniques for industrial imaging. An ECT technique is nonintrusive and rapid and requires a low burden cost. However, the ECT system still suffers from a soft-field problem which adversely affects the quality of the reconstructed images. Although many image reconstruction algorithms have been developed, still the generated images are inaccurate and poor. In this work, the Capacitance Artificial Neural Network (CANN) system is presented as a solver for the forward problem to calculate the estimated capacitance measurements. Moreover, the Metal Filled Fuzzy System (MFFS) is proposed as a solver for the inverse problem to construct the metal images. To assess the proposed approaches, we conducted extensive experiments on image metal distributions in the lost foam casting (LFC) process to light the reliability of the system and its efficiency. The experimental results showed that the system is sensible and superior.

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“…Such carbon defects begin to occur when the liquid metal is poured into the mold cavity, which results in thermal degradation and/or forces the polystyrene pattern to emit hydrocarbon gases. The products of the thermal decomposition of the Styrofoam pattern exit through the refractory coating and sand to the outside of the mold [10,11]. The defect in the form of lustrous carbon occurs when the molding compounds used to fill the mold with liquid metal generate large amounts of carbon material decomposition products (i.e., lustrous carbon carriers).…”

Section: Introductionmentioning

confidence: 99%

The Impact of Process Factors on Creating Defects, Mainly Lustrous Carbon, during the Production of Ductile Iron Using the Lost-Foam Casting (LFC) Method

Jezierski

Jureczko

Dojka

2020

Metals

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The purpose of this paper was to analyze the process factors affecting the occurrence of lustrous carbon defects in ductile cast iron castings when using the lost-foam casting (LFC) method. This phenomenon results in creating raw surface defects, which sometimes may even lead to cast iron scrapping. A series of trial melting batches were carried out for variable process assumptions. The analysis was performed to reflect, to the greatest extent possible, real foundry production conditions. Industrial tests were performed in Odlewnia Rafamet Sp. z o.o., Kuźnia Raciborska, Poland. The polystyrene patterns created by gluing components together, used in the tests, met the requirements of the high-tech lost-foam casting (LFC) process. The performed analysis allowed the obtaining of lustrous carbon defects in test castings as well as the determination of the process parameters with the highest impact on lustrous carbon inclusions in ductile iron castings. The test results were used to eliminate the possibility of creating a defect and thus directly improve the efficiency of the lost-foam casting (LFC) process used in the foundry.

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Instability of the Liquid Metal–Pattern Interface in the Lost Foam Casting of Aluminum Alloys

Cited by 24 publications

References 17 publications

Gas Pressure Effect on Sand Collapse in Kinetic Zone of Lost‐Foam Casting

Gas Pressure Effect on Sand Collapse in Kinetic Zone of Lost‐Foam Casting

Application of Electrical Capacitance Tomography for Imaging Conductive Materials in Industrial Processes

The Impact of Process Factors on Creating Defects, Mainly Lustrous Carbon, during the Production of Ductile Iron Using the Lost-Foam Casting (LFC) Method

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