Refining aluminium-alloy melts with graphite rotors

Lichý, Petr; Bajerová, Martina; Kroupová, Ivana; Obzina, Tomáš

doi:10.17222/mit.2019.147

Cited by 8 publications

(6 citation statements)

References 1 publication

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“…Regardless of the casting cycle mastering, the quality of the cast is primarily dependent on the quality of the input raw material, its melting and subsequent metallurgical treatments. To enable the production to be profitable, lower quality input materials are often used today, which, although they have the required chemical composition, may contain a relatively large number of impurities, originating not only from the original input materials, but also from their processing [ 12 , 13 ]. Impurities entering the process during remelting and casting are one of the primary causes of foundry defects and have negative impact on the mechanical properties of casted Al-Si components [ 14 , 15 ].…”

Section: Introductionmentioning

confidence: 99%

Aluminum Melt Degassing Process Evaluation Depending on the Design and the Degree of the FDU Unit Graphite Rotor Wear

et al. 2022

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One of the most important indicators of casting quality is porosity. The formation of pores is largely conditioned by the presence of hydrogen in the batch and subsequently in the melt. The gasification of the melt is the primary factor increasing the porosity of casts. This paper addresses the issue of reducing the melt gasification by using FDU (Foundry Degassing Unit) unit. The gas content in the melt is evaluated by determining the Dichte Index depending on the geometry and the degree of the FDU unit rotor wear. For experiments performed under the operating conditions, three types of graphite rotors with different geometries are used. The extent of melt gasification and the Dichte Index are monitored during the rotor wear, at a rate of 0%, 25%, 50%, 75% and 100% rotor wear. Secondly, the chemical composition of the melt is monitored depending on the design and wear of the rotor. It is proven that the design and the degree of rotor wear do not have significant effect on the chemical composition of the melt and all evaluated samples fell within the prescribed quality in accordance with EN 1706. With regard to the overall comparison of the geometry and wear of individual rotor types, it has been proven that, in terms of efficiency, the individual rotors are mutually equivalent and meet the requirements for melt degassing throughout the service life.

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Section: Introductionmentioning

confidence: 99%

Aluminum Melt Degassing Process Evaluation Depending on the Design and the Degree of the FDU Unit Graphite Rotor Wear

et al. 2022

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“…Nowadays, aluminium alloys enable to replace materials with higher weight and thus reduce fuel consumption and emissions. It is due to their suitable combination of mechanical properties and a wide range of usage, because aluminium alloys have high ratio of strength to weight, corrosion resistance, low melting point, good casting and thermal properties and especially light weight overall [1][2][3][4][5]. The use of aluminium alloys in the automotive and aerospace industry is related to increasing demands of casting quality.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation and Experimental Validation of Melt Flow in the Naturally Pressurized Gating System

2021

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The main problem during the production of castings from aluminium alloys is the presence of the reoxidation, which negatively affects the final casting quality. Liquid metal surface reacts with the surrounding atmosphere and oxide layer of Al2O3 is formed on its surface. The problem occurs when the oxide layer is entrained to the internal volume of the melt by turbulence and double oxide layers are formed, also known as “bifilms”. Its formation is related to the melt velocity and gating system design. In paper, naturally pressurized gating system was calculated and designed. Effect of the filter media and vortex element on the melt velocity, amount of oxides, mechanical properties, and porosity were observed. Designs with 10 ppi and 20 ppi foam filters and vortex element were compared with design without filters to prove the positive (or negative) effect of filter media on melt velocity and thus on final casting quality. The melt velocity and amount of oxides were observed with the aid of simulation software. Mechanical properties, quantity of pores, bifilm index and EDX analysis were evaluated after experimental casts. It was proven that by using 20 ppi foam filter in combination with vortex element, the best results were achieved.

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“…The refining principle at FDU unit is illustrated in Figure 3. TheFDU unit is characterised by a variability of process parameters; by changing these parameters, it is possible to affect the course and efficiency of the refining process [9][10][11][12][13][14]. These parameters include the impeller type, rotation frequency, working height, inert gas flow rate and the number of baffles.…”

Section: Introductionmentioning

confidence: 99%

Optimization of operating conditions of aluminum melt refining process in laboratory conditions

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Gryc

Sviželová

et al. 2021

METAL 2021 Conference Proeedings

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Refining aluminium-alloy melts with graphite rotors

Cited by 8 publications

References 1 publication

Aluminum Melt Degassing Process Evaluation Depending on the Design and the Degree of the FDU Unit Graphite Rotor Wear

Aluminum Melt Degassing Process Evaluation Depending on the Design and the Degree of the FDU Unit Graphite Rotor Wear

Numerical Simulation and Experimental Validation of Melt Flow in the Naturally Pressurized Gating System

Optimization of operating conditions of aluminum melt refining process in laboratory conditions

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