Modelling of semi-continuous casting of cupro-nickel alloys

This research developed at University of Liege aims to optimize the complete
semi-continuous casting process at LBP Company, a producer of copper-nickel alloys (or
cupro-nickels). The process consists in vertical casting of 7m long ingots. Some problems
recurrently occur during casting process: formation of oscillations (wave length of about
500 mm), unsuitable concave cross-sections or internal cracks. In order to reduce the
occurrence of such defects and to better understand their formation, we have been asked
to develop a finite element model.
The research focuses on two main topics: identification of material properties through
laboratory tests and literature survey and the development of the numerical tool. The
laboratory tests provide thermal and mechanical properties of the ingot and the mould, as
well as heat transfer coefficients between the ingot and its surroundings (mould, air and
water). These parameters are required for the numerical simulations of the process.
In the second part of the research, numerical calculations have been performed using finite
element method. Two types of 2D models have already been studied: horizontal slice and
vertical slice. This first choice has been guided by the high coupling between thermal and
mechanical aspects of the problem, leading to highly complex systems of equations and
subsequent long CPU times. However, due to the limitations of such 2D models, a 3D
formulation has then been considered and it is still in progress.