Projektmenu

Introduction

In the process of flat steel production, a significant amount of energy is required for the treatment of the slabs produced in the continuous casting process (e.g. scarfing, re-heating and rolling). For the industrial partner voestalpine Stahl GmbH, the goal is a “zero defect production”. This requires precise quality detection as early in the process as possible. By now the quality of the produced slabs can only be analysed offline in small samples or near the end of the whole production process. For an increase of the process efficiency and a reduction of the consumed energy and resources, it is thus necessary to determine the steel quality online during the continuous casting process.

The liquid steel flow in the mould, especially the flow near the mould level, significantly influences the quality of the produced steel. Therefore the proper setting of process parameters (e.g. casting speed, argon injection rate but also the geometry of the submerged entry nozzle) is important.

  • CFD simulation of mould flow of continuous casting equipment
  • Validation of simulations using water flow experiments
  • Development of a global model with adapted control parameters for real-time quality assessment
  • Implementation of the model in the framework of the control system of a continuous caster
  • Compilation of a data base from water models, numerical simulations and plant data
  • Fast (near real-time) CFD approaches

Methodology

The project has two goals. The first one is to develop best practice guide lines for the liquid steel flow in continuous casting. The second goal is the development of an online quality assessment system which provides the steel plant with additional information on the mould flow which is relevant for the quality of the cast product.

These two goals will combine three main lines of investigation:

  • Numeric modelling: A wide range of models is available in the field of numerical flow modelling. For this project the focus of investigation is to find numerical models which are capable of running online at the plant.
  • Analytical modelling: For some isolated phenomena governing the liquid steel flow in the mould analytical solutions (e.g. surface waves) already exist. These analytical models are valuable as they show trends in a large parameter space and help to gain a better understanding of the basic dynamics and thus support the process of empirical modelling or reduced CFD (computational fluid dynamics) modelling.

Empirical models are state of the art to characterize the mould flow online. These models are usually based on plant data, physical and numerical model results. In the course of this project the range of validity of known empirical models and possible ways of expansion will be checked.

Results and application

Project 4.5 will provide realtime insight into the mould of the continuous casting process flow, opening the door towards online quality monitoring and advanced process control. The model is expected to lead to a more accurate and reliable quality prediction of the cast product. This is highly important for steel producers because this online prediction will reduce expenses for subsequent processes necessary for guaranteeing slab quality (e.g. scarfing of slabs). Thus this project is expected to lead to an increase in efficiency and to a reduction of energy and resource consumption of the steel casting process. Industrial partner voestalpine Stahl GmbH will assure the implementation of scientific results by conducting corresponding plant trials.