The Effect of Fluxes on the Melt Quality of AlSi7MgCu Alloy

Gyarmati, Gábor; Fegyverneki, György; Mende, Tamás; Tokár, Mónika

doi:10.21791/ijems.2019.1.46.

Cited by 7 publications

(11 citation statements)

References 7 publications

(8 reference statements)

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“…From the results of this work, it can be concluded that the refining efficiency of different fluxes is highly dependent on their chemical composition, melting temperature, and wettability with aluminum oxide, which agrees with the conclusions of Gyarmati et al [ 15 ]. The ten fluxes in this work all have significantly lower melting temperatures than the refining temperature, which is a prerequisite to enable the fluxes to have a refining effect in the melt.…”

Section: Resultssupporting

confidence: 91%

“…An OCA25–HTV 1800 was used for the high-temperature contact angle test. According to Gyarmati [ 15 ], Li [ 18 ], Chen [ 27 ], Wan [ 28 ], and Fu et al [ 9 ], the most common oxide inclusions within the aluminum melt are aluminum oxide. Because the aluminum oxide inclusions within the aluminum melt show an amorphous state, taking the form of strings and films, it is hard to study the contact angle between the fluxes and the actual aluminum oxide.…”

Section: Methodsmentioning

confidence: 99%

“…These inclusions cluster, causing the formation of pores in aluminum [ 9 ]. To remove these nonmetallic inclusions, scholars have developed a variety of methods, such as sedimentation, ultrasonication, bubble floatation, filtration [ 10 , 11 ], electromagnetic stir technology [ 12 , 13 , 14 ], flux refining [ 15 ], and so on. Among them, flux refinement is widely used in industrial production, because of its low cost and operational simplicity.…”

Section: Introductionmentioning

confidence: 99%

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A New Strategy on Designing Fluxes for Aluminum Alloy Melt Refinement

Zhang

et al. 2023

Materials

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With the aim of obtaining a refining flux that is stable and provides effective refining of aluminum melt, a new strategy of designing the flux composition has been proposed. Ten fluxes were designed, by selecting ten molten salt compounds according to their thermophysical parameters, physical properties, and thermodynamic analysis. The melting points of the ten fluxes, and the phases transformation of the fluxes after melting, were studied by DSC and XRD, respectively. The contact angles between four groups of fluxes and alumina at refinement temperatures were studied, and the effect of refinement was characterized by a metallographic microscope. The process of the fluxes removing inclusions and degassing was analyzed thermodynamically. The research findings indicate that flux #10 (11.0 wt.%NaF, 29.5 wt.%NaCl, 46.5 wt.%Na2CO3, 3.0 wt.%CaF2, 10.0 wt.%Na3AlF6) has a melting point (562.2 °C) below the refining temperature. At the refining temperature (760 °C), flux #10 has the lowest contact angle, of 12.78°. In addition, compared to that of flux STJ–A3, currently used in practice, flux #10 has a better refining effectiveness, with the pores and inclusions content of the sample being reduced to 1.11% from 2.96%.

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Section: Resultssupporting

confidence: 91%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A New Strategy on Designing Fluxes for Aluminum Alloy Melt Refinement

Zhang

et al. 2023

Materials

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“…where K is the K-mold value (dimensionless number), n is the number of examined fracture surfaces, and S is the total number of inclusions found in n pieces [35,36]. The surface of the found inclusions was investigated with a Zeiss EVO MA 10 scanning electron microscope (SEM) equipped with an energy-dispersive X-ray spectroscopy (EDS) system.…”

Section: Melt Quality Assessmentmentioning

confidence: 99%

Investigation on Double Oxide Film Initiated Pore Formation in Aluminum Casting Alloys

Gyarmati,

Fegyverneki,

Tokár

et al. 2020

IJEMS

Self Cite

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The most common, and in fact, the most deleterious defects of aluminum casting alloys are the so-called double oxide films or bifilms, which have a central role in porosity formation, as they can easily unfurl and inflate into pores during the solidification of the alloys. Sr addition is generally used in the foundry industry for the modification of the eutectic Si phase of hypoeutectic Al-Si alloys. However, Sr microalloying usually leads to an increased pore formation tendency. As bifilms are preferred sites for pore formation, it should be expected that Sr additions have a significant effect on the number and/or the structure of double oxide films present in the melt. In this work, the relationship between Sr-concentration and the susceptibility to pore formation has been investigated through the evaluation of melt quality of melts which had different levels of Sr. The bifilm content of the melts was investigated by the analysis of K-mold specimens and X-ray computed tomography (CT) of reduced pressure test (RPT) samples. It was found that liquid alloys with a higher Sr concentration had a significantly greater tendency to pore formation, which can be explained by the presence of a larger number of bifilm defects in the liquid alloy.

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“…The mechanism is the improvement of fluidity due to the heat released by exothermic reactions [21]. Moreover, when added with fluorides, the heat released facilitates the chemical reactions between fluorides and inclusions [34]. Examples of oxidizing agents include nitrates such as KNO 3 and NaNO 3 , carbonates such as CaCO 3 and K 2 CO 3 and sulfates such as K 2 SO 4 and Na 2 SO 4 [24].…”

Section: Oxidizing Agentsmentioning

confidence: 99%

Solid Salt Fluxes for Molten Aluminum Processing—A Review

Milani

Timelli

2023

Metals

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Aluminum recycling is a promising solution to environmental and economic issues. Secondary aluminum production will rise in the near future; however, the process is not without challenges. Some of the major concerns during remelting of aluminum are the metal losses due to the oxidation of the molten metal and the removal of impurities from the metal bath. The current study summarizes the latest progress in the use of solid salt fluxes for secondary aluminum production and the treatment of molten metal. The chemistry of solid fluxes has been reviewed, with a correlation to their main chemical and physical characteristics, such as density, fluidity, wettability, and reactivity. An overview of the main types of solid fluxes is also provided, with a particular focus on their functions and applications. The efficiency of solid fluxes relies on several factors, including but not limited to the fluxes’ chemical composition and physical properties, flux amount, processing temperature, and flux morphology. The effect of salt fluxes in delivering satisfactory metal cleanliness and sufficient metal recovery has been summarized according to the main flux’s properties.

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The Effect of Fluxes on the Melt Quality of AlSi7MgCu Alloy

Cited by 7 publications

References 7 publications

A New Strategy on Designing Fluxes for Aluminum Alloy Melt Refinement

A New Strategy on Designing Fluxes for Aluminum Alloy Melt Refinement

Investigation on Double Oxide Film Initiated Pore Formation in Aluminum Casting Alloys

Solid Salt Fluxes for Molten Aluminum Processing—A Review

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