Stahl Gerlafingen Benefits from Improved Production Performance after Wire Rod Mill Upgrade

• New laying head significantly reduces heavy vibrations, ensuring no more costly unexpected shutdowns
• Increases Stahl Gerlafingen’s production utilization by improving yield through reduced unexpected conveyor stops and maintenance downtime
• Tension monitoring system improves front-end orientation for a more uniform coil package

Primetals Technologies recently received the final acceptance certificate (FAC) for an upgrade to AFV Beltrame Stahl Gerlafingen’s wire rod mill in Gerlafingen, a city in the canton of Solothurn, located in the north-western part of Switzerland. The upgrade included an intelligent pinch roll and laying head utilizing electrical motors and drives, along with an automation system. The mill’s wire rod outlet will produce 600,000 tons per year of 6 – 20 millimeter quenched rebar and 5.5 – 20 millimeter low carbon wire rod.

Stahl Gerlafingen’s previous laying head caused multiple issues, including excessive vibration that led to unplanned shutdowns, poor front-end orientation, and uneven coil package. To address these issues, Stahl Gerlafingen contracted Primetals Technologies whose 6^th-generation laying head provided the necessary solution.

An Updated Laying Head

The updated laying head technology incorporates an integral segmented deflector plate for front and tail end control, as well as a rugged gear box with roller bearings. This new generation’s one-piece fabrication design reduces manufacturing time and provides a reduced second harmonic. The improved pipe path and center of gravity (CG) position contributes to a reduction in vibrations and enables long-lasting pipe paths with less wear.

The new laying head includes a tension monitoring system utilizing laser speed gauges to measure product movement and position. The new solution immediately improved front end orientation once installed and running. This effectively removed vibrations, significantly reducing unplanned mill stops and increasing production.

Christiane Hess, Technical Project Manager for Stahl Gerlafingen, commented on the new Laying Head’s performance saying, “Thanks to the new screw technology, both the start and end of the coil are now placed significantly more precisely and stably in the coil formation area. Additionally, the new equipment allows for higher production speeds and a more powerful drive mechanism, improving overall process stability and product quality.”

Real-Time Product Monitoring

The tension monitoring control system measures how fast the product coming in and out of the laying head is moving, along with its position. Integrating with the mill’s existing human-machine interface (HMI), this allows operators a unique opportunity to not only monitor product in real-time, but to make informed decisions based on process data.

Producing an average of over 700,000 tons of low-CO₂ steel each year, Stahl Gerlafingen is the largest producer of recycled steel in Switzerland. Founded over 200 years ago in 1823, the company is a supplier of steel bars and beams within AFV Beltrame Group.