NLMK increased the productivity of its coil galvanizing line in France

NLMK France is investing in process control at its 400,000 tpa galvanizing line in Strasbourg to improve productivity and prevent human errors.

The manufacturer installed a predictive furnace control system developed by French equipment manufacturer Fives called VirtuoTM. According to Fives, the digital system was customized to suit the furnace and the need to improve quality while limiting waste.

While modern lines are equipped with gradual temperature increases, the Strasbourg line is equipped with an oven that provides rapid temperature increases over short distances. Improved control of temperature changes allows you to avoid defects, as well as financial losses.

“Conventional control methods proved inadequate due to delays, downtime and non-linear process effects... The implementation of VirtuoTM-L began with simple modeling based on physics equations and complex parameters to adapt to an atypical furnace. It later evolved into a hybrid model that combined recorded data with automated odds calculations,” Fives tells Callanish.

“This transformation allowed the furnace to compensate for physical phenomena not accounted for by the original model,” he adds.

The adapted solution is now able to read the furnace's response to temperature changes. With a kiln inlet gloss meter that measures the brightness of the strip, it allows kiln changeovers to address quality issues related to the surface condition of incoming rolls.

The adapted system made it possible to constantly improve product quality, reduce the number of low-quality rolls and simplify the work of operators, NLMK said in a joint statement.