Effects of melt temperature and casting speed on the structure and defect formation during direct-chill casting of an Al-Cu alloy

Eskin, Dmitry; Savran, V.I.; Katgerman, L.

doi:10.1007/s11661-005-0059-6

Cited by 86 publications

(81 citation statements)

References 16 publications

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“…Computer simulations of directchill casting confirm that the increase in melt temperature deepens the sump (region 1 + 2, see Fig. 2a) and narrows the transition region (region 2) by shifting both the liquidus and the solidus isotherms downwards [25,33]. But liquidus position is affected to a greater extent.…”

Section: Effect Of DC Casting Process Parametersmentioning

confidence: 76%

Macrosegregation in direct-chill casting of aluminium alloys

Nadella

Eskin

et al. 2008

Progress in Materials Science

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248

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Semi-continuous direct-chill (DC) casting holds a prominent position in commercial aluminium alloy processing, especially in production of large sized ingots.Macrosegregation, which is the non-uniform chemical composition over the length scale of a casting, is one of the major defects that occur during this process. The fact that macrosegregation is essentially unaffected by subsequent heat treatment (hence constitutes an irreversible defect) leaves us with little choice but to control it during the casting stage. Despite over a century of research in the phenomenon of macrosegregation in castings and good understanding of underlying mechanisms, the contributions of these mechanisms in the overall macrosegregation picture; and interplay between these mechanisms and the structure formation during solidification are still unclear. This review attempts to fill this gap based on the published data and own results. The following features make this review unique: results of computer simulations are used in order to separate the effects of different macrosegregation mechanisms. The issue of grain refining is specifically discussed in relation to macrosegregation. This report is structured as follows. Macrosegregation as a phenomenon is defined in the Introduction. In Part 2, direct-chill casting, the role of process parameters and the evolution of structural features in the as-cast billets are described. In Part 3, macrosegregation mechanisms are elucidated in a historical perspective and the correlation with DC casting process parameters and structural features are made. The issue of how to control macrosegregation in direct-chill casting is also dealt with in Part 3. In Part 4, the effect of grain refining on macrosegregation is introduced, the current understanding is described and the contentious issues are outlined. The review is finished with conclusion remarks and outline for the future research.

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Section: Effect Of DC Casting Process Parametersmentioning

confidence: 76%

Macrosegregation in direct-chill casting of aluminium alloys

Nadella

Eskin

et al. 2008

Progress in Materials Science

Self Cite

248

148

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“…They also affirm that the porosity of the solid-state metal occurs due to the liquid incapacity to fill the bubbles during the metal continuous cooling and solidification (the volume shrinkage associated with solidification cannot be compensated by the interdendritic flowing opposite to the displacement of the isotherms). All those variables affect the amount, size and morphology of formed pores [1][2][3][4][5][6][7] . Gali…”

Section: Methodsmentioning

confidence: 99%

“…Some studies about the Direct Chill process showed that, the melt temperature and casting speed have a great influence on solid macrossegregation and on billet porosity [1][2][3] . The porosity of the obtained solid-state metal has a strong influence on subsequent forming process, especially on aluminum alloy rolling.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Casting Speed and the Fraction of Al5%Ti1%B Inoculant on the Microstructure and Mechanical Properties of the AA5052 Aluminum Alloy Produced by the Direct Chill Process

Faria

Leite

2018

Mat. Res.

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This study aimed to assess the effect of casting speed and the addition of Al5%Ti1%B inoculant in the casted AA5052 aluminum alloy plate manufactured by the Direct Chill process. The focus of this work was to decrease the rejection index of rolled products due to the occurrence of superficial flaws on plates. These defects impact directly on the production costs and on the rolled product quality. The main cause of those flaws is associated with the billet porosity that is related with the excess of atomic hydrogen incorporated into the metallic bath and with the metal shrinkage during solidification. Four different cast conditions were industrially tested, combining two casting speeds and two inoculants amounts. The effect of those variables on the alloy mechanical properties and on their performance in rolling process was also assessed. It was observed that the higher the casting speed and the inoculant fraction, the more refined the microstructure and the lower the fraction and diameter of formed micropores. The increase of casting speed and the inoculant fraction improved the AA5052 alloy rolling performance. The application of these results in an industrial scale performed a decrease from 5.03% to 0.39% per month in the rejection index of rolled products.

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“…These are provoked by higher energy extraction rates at the water impingement point to keep the system under equilibrium. Faster casting velocities require a corresponding hike in heat flux, as more heat is removed from the ingot [21,22].…”

Section: Casting Velocitymentioning

confidence: 99%

Depicting Aluminium DC Casting by Means of Dimensionless Numbers

Méndez¹,

Ambriz²,

Jaramillo³

et al. 2018

Advanced Casting Technologies

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DC casting of aluminium and its alloys is a controlled heat removal solidification process. The rate of heat extraction has strong effects on the microstructure and mechanical properties of the solidified alloy ingots. In view of this strict temperature, control over the ingot as it solidifies should be implemented in order to achieve metal with the best possible properties. In situ direct temperature measurements are complicated; so in this report, the use of dimensionless analysis to predict temperature distributions on the ingots as they are casted is proposed. It is reported that the dimensionless groups that better represent the impact of process variables on the solidification of aluminium and its alloys are the Péclet (Pe) and Biot (Bi) numbers.

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Effects of melt temperature and casting speed on the structure and defect formation during direct-chill casting of an Al-Cu alloy

Cited by 86 publications

References 16 publications

Macrosegregation in direct-chill casting of aluminium alloys

Macrosegregation in direct-chill casting of aluminium alloys

The Effect of Casting Speed and the Fraction of Al5%Ti1%B Inoculant on the Microstructure and Mechanical Properties of the AA5052 Aluminum Alloy Produced by the Direct Chill Process

Depicting Aluminium DC Casting by Means of Dimensionless Numbers

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