Prediction of Periodic Centerline Porosity and Pulse Marks by CFD and Experimentation for Continuously Cast Copper

For 8 mm OFCu rod, the formation of pulse mark defects on the exterior of the rod and periodic macroporosity (> 1 mm diameter pores) occurring internally along the centerline of the castings have been observed and noted to limit the maximum attainable withdrawal rates (~ 4 m/s). Conversely, the s...

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Bibliographic Details
Published in:Metallurgical and materials transactions. B, Process metallurgy and materials processing science Process metallurgy and materials processing science, 2023-04, Vol.54 (2), p.499-514
Main Authors: Jones, Thomas D. A., Strachan, Richard, Russell, Kyle, Abdullah, Mustafe, Mackie, David M., Cooper, Mervyn, Frame, Brian, Vorstius, Jan B.
Format: Article
Language:English
Subjects:
Boundary conditions
CAD
Casting defects
Castings
Characterization and Evaluation of Materials
Chemistry and Materials Science
Computed tomography
Computer aided design
Continuous casting
Dynamic models
Experimentation
Fluid dynamics
Grain growth
Macroporosity
Materials Science
Metallic Materials
Metallurgical analysis
Nanotechnology
Original Research Article
Physical properties
Porosity
Rods
Simulation
Solidification
Structural Materials
Surfaces and Interfaces
Tensile tests
Thin Films
Tomography
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Summary:For 8 mm OFCu rod, the formation of pulse mark defects on the exterior of the rod and periodic macroporosity (> 1 mm diameter pores) occurring internally along the centerline of the castings have been observed and noted to limit the maximum attainable withdrawal rates (~ 4 m/s). Conversely, the same casting defects have been witnessed for slower rates; therefore, investigations were performed to investigate how the casting motions (withdrawal, dwell, and pushback) formed these defects and could be prevented. Characterization of the physical properties of the cast rods by tensile testing and analysis by optical and computed tomography (CT) imaging revealed correlations to the outer pitch length marks on the rods and confirmed relationships to casting motions and pitch lengths evaluated from metallurgical equations. Computational fluid dynamic modeling using Ansys Fluent v.R1 was applied to quantify the localized formation and dissipation of periodic hotspots internally within the die for the different motions. A mechanism leading to periodic porosity was identified, which was irrespective of the average casting withdrawal rates and enabled prediction of the location, frequency, and magnitude of the macroporosity defect.
ISSN:1073-5615
1543-1916
DOI:10.1007/s11663-022-02704-1