Successful thermal performance at NLMK Strasbourg
NLMK Strasbourg, a steelmaker of galvanized and pre-painted steel for the automotive and construction sectors, was looking for a solution to improve coil quality produced by its existing galvanizing line of 400, 000 tonnes annual capacity.
The line featured a horizontal, short but very powerful furnace that generated rapid temperature increases over short distances, unlike modern lines that are longer with gradual temperature rises. Temperature variations were the primary source of these problems, leading to rejects and financial losses. Conventional control methods proved inadequate due to latencies, downtime, and non-linear process effects.
How Virtuo™-L meet steelmaker’s expectations
The team introduced a predictive furnace control solution - Virtuo™-L developed by Steel Digital Factory, to NLMK to overcome quality issues.
"The heart of the challenge laid in anticipating the furnace's behavior. If we could predict the furnace's response to temperature variations, informed decisions could be made to maintain product quality," explains Antoine Bonnemaison, Head of Transformation at NLMK Strasbourg.
This challenge required significant adjustments to ensure Virtuo™-L could adapt to the unique configuration.
The deployment of Virtuo™-L began with simple modeling based on physical equations and complex parameters to adjust to the atypical furnace. Later, it transformed into a hybrid model, combining recorded data with automatic coefficient calculations. This transformation allowed the furnace to compensate for physical phenomena not captured by the initial model.
Operators were educated about the changes introduced by the model, particularly with regard to furnace power and line speed. Understanding the process managed by a digital solution was an important step forward in their daily operational life.
Achieving the impossible
Implementing the Virtuo™-L solution had a substantial impact on the project.
A key innovation in the project was resolving a problem that was linked to the quality of incoming steel coils and marked by high variability due to the strip's surface condition. A gloss meter was introduced at the furnace's entrance to measure strip brightness, thus enabling anticipation of behavior variations and furnace readjustments.
"Despite a challenging start due to the furnace's unique qualities, this project represents a significant success with great potential. Fives has proven its ability to understand our needs by highly customizing its solution which resulted in continuous improvement of product quality, reduction of downgraded coils, and simplification of the operators’ work. We have a unique solution that pays back its investment," adds Antoine Bonnemaison.