Abstract 

This report contains an investigation of the annealing process of an aluminium coil in industrial furnace environment. The main result of this investigation is a predictive FE simulation model within adequate accuracy which aids in annealing process design.

The procedure starts with a literature study of both the key parameters in general and the modelling and experimental methods related to heat transfer in industrial coils. Additional CAE tools are identified to support the research.

The procedure follows the implementation of the existing radial thermal conductivity model in a FE simulation, for different coil thicknesses and winding forces. The measured strip surface roughness and the crowning slope serve as input parameters in the effective radial thermal conductivity model.

Furthermore, the effective heat transfer coefficient models for coil sides have been developed and calibrated. Both the radial thermal conductivity and convective heat transfer models are integrated in the FE model of the coil annealing process.

The coil annealing experiments have been conducted in an industrial furnace at Gränges AB. The experimental data support the creation and validation of the FE simulation model.

The simulation-based parametric study evaluates the importance of considering the relevant physical phenomena in the model.

The FE model of the annealing process has been validated against the temperature measurements within 10% at the target material temperature. The model can be applied for coil temperature predictions as part of the annealing process design.

The overall method generates engineering guidelines to design the annealing process with the help of simulation tools.