A multiphysics and multiscale model for low frequency electromagnetic direct-chill casting

• Published in: IOP conference series. Materials Science and Engineering 2016-03, Vol.117 (1), p.12052-12058
• Main Authors: Košnik, N, Guštin, A Z, Mavri, B, Šarler, B
• Format: Article
• Language: English
• Subjects: Aluminum base alloys; Billet casting; Casting; Chill casting; Coils; Collocation methods; Deformation; Direct chill casting; Electromagnetic fields; Electromagnetic induction; Finite element method; Grain size; Grain structure; Levitation casting; Liquid phases; Lorentz force; Low frequencies; Mathematical analysis; Mathematical models; Meshless methods; Phase diagrams; Post-processing; Process parameters; Radial basis function; Rheological properties; Rheology; Solid phases; Thermodynamics; Velocity coupling
• ISSN: 1757-8981; 1757-899X
• DOI: 10.1088/1757-899X/117/1/012052

Simulation and control of macrosegregation, deformation and grain size in low frequency electromagnetic (EM) direct-chill casting (LFEMC) is important for downstream processing. Respectively, a multiphysics and multiscale model is developed for solution of Lorentz force, temperature, velocity, concentration, deformation and grain structure of LFEMC processed aluminum alloys, with focus on axisymmetric billets. The mixture equations with lever rule, linearized phase diagram, and stationary thermoelastic solid phase are assumed, together with EM induction equation for the field imposed by the coil. Explicit diffuse approximate meshless solution procedure [1] is used for solving the EM field, and the explicit local radial basis function collocation method [2] is used for solving the coupled transport phenomena and thermomechanics fields. Pressure-velocity coupling is performed by the fractional step method [3]. The point automata method with modified KGT model is used to estimate the grain structure [4] in a post-processing mode. Thermal, mechanical, EM and grain structure outcomes of the model are demonstrated. A systematic study of the complicated influences of the process parameters can be investigated by the model, including intensity and frequency of the electromagnetic field. The meshless solution framework, with the implemented simplest physical models, will be further extended by including more sophisticated microsegregation and grain structure models, as well as a more realistic solid and solid-liquid phase rheology.