Rolling Mill Electrical Control Systems Accelerate Upgrades as Automation Modernization Gains Momentum

In recent years, electrical control systems in steel production have been moving from conventional equipment control toward automation, digitalization and intelligent process management.

For hot and cold rolling mills that have been operating for many years, the mechanical equipment may still have considerable remaining service life, while the original PLCs, drives, control cabinets and automation systems may face component aging, discontinued spare parts and increasing maintenance difficulties.

As a result, electrical and automation modernization is becoming an increasingly important part of rolling mill upgrade projects.

1. Automation Upgrades Are Already Being Implemented in Cold Rolling Mills

In July 2025, SMS group announced a contract from thyssenkrupp Electrical Steel (tkES) to upgrade the automation system of an existing cold rolling mill.

The project focuses on modernizing automation technology for the existing production line, with the aim of improving reliability and control performance.

The project illustrates an important industry trend: for existing cold rolling mills, steel producers do not necessarily need to replace the entire mechanical production line. Instead, modernizing the automation system can extend the useful life of existing equipment while improving its operational capabilities.

2. PLC and Process-Control Systems Are Key Upgrade Areas

A modern rolling mill electrical control system can involve multiple control levels, including:

• PLC control systems
• HMI operator systems
• Main drive control
• Speed control
• Tension control
• Automatic Gauge Control (AGC)
• Hydraulic control
• Field instruments and sensors
• Data acquisition and production monitoring systems

As older control systems become obsolete, upgrading PLCs, HMIs and industrial communication systems can improve data exchange, system response and overall equipment control.

For cold rolling mills in particular, electrical systems need to work closely with AGC, tension control and main drive systems. Therefore, electrical modernization is not simply a matter of replacing a control cabinet; it can involve optimization of the control logic across the production line.

3. Main Drives and Drive Systems Are Also Major Modernization Targets

Rolling mill main drives operate large motors and therefore have a direct impact on production reliability.

Primetals Technologies continues to provide motor and drive modernization solutions for steel plants, highlighting modernization as a way to maintain equipment performance and extend the lifecycle of existing drive systems.

For aging rolling mills, upgrading main motors, drives, variable-frequency drives and associated control equipment can help address obsolete electrical components and improve operational stability.

4. Minimizing Production Interruptions Is Becoming More Important

Rolling mills are typically continuous-production assets, meaning that extended shutdowns for modernization can result in significant production losses.

As a result, the ability to complete electrical and automation upgrades while minimizing production downtime is becoming an increasingly important requirement.

In December 2025, Danieli published a rolling mill automation modernization case focusing on upgrading the automation control system within a short timeframe while minimizing disruption to normal plant operations.

This indicates that future electrical modernization projects will need to consider not only system performance, but also the entire implementation process:

Preparation → Installation → System Changeover → Commissioning → Production Recovery

Reducing the time required for each stage can be critical for steel producers.

5. Electrical Modernization Is Increasingly Linked to Energy Efficiency

Modern electrical control systems can also support more accurate energy management.

By collecting data such as motor current, power, speed and load, operators can analyze electricity consumption during different stages of rolling production.

Modern drive systems can also adjust motor operation according to actual load conditions, helping improve energy efficiency.

Therefore, the role of rolling mill electrical systems is gradually expanding from simply:

“Controlling equipment”

to:

“Control + Monitoring + Data Acquisition + Energy Management + Production Optimization.”

6. Modern Control Systems Improve Maintenance Capability

A common challenge with aging rolling mills is that the mechanical equipment may still be operational while the original electrical components have become difficult to maintain.

Some early-generation PLCs, drives and control modules are no longer manufactured, leaving steel producers dependent on existing spare-parts inventories or replacement solutions.

Modernization can replace obsolete control components with systems that continue to receive technical support.

New HMI and monitoring systems can also provide operators and maintenance personnel with clearer information about:

• Motor operating status
• Drive conditions
• Alarm and fault information
• Rolling parameters
• Temperature and pressure
• Production data

This can help maintenance teams identify abnormal conditions more quickly and reduce troubleshooting time.

Market Trends

Recent rolling mill modernization projects indicate several key trends in electrical control:

Modernization of Aging Systems
Replacing outdated PLCs, HMIs, drives and control cabinets to extend equipment service life.

Higher Automation Levels
Moving from individual machine control toward integrated production-line control and data management.

Drive System Upgrades
Using modern motor and drive technologies to improve reliability and energy performance.

Reduced Production Downtime
Using phased modernization, pre-commissioning and rapid system changeover to minimize production interruptions.

Integration with Digital Technologies
Combining equipment control with production data, energy monitoring and equipment condition information.

Conclusion

Overall, rolling mill electrical control systems are becoming an increasingly important part of steel equipment modernization.

Recent projects—including SMS group's automation upgrade for a thyssenkrupp Electrical Steel cold rolling mill, Danieli's automation modernization solutions and Primetals Technologies' motor and drive modernization services—demonstrate the industry's growing focus on extending the lifecycle and improving the performance of existing rolling equipment.

Going forward, rolling mill electrical systems are expected to develop beyond PLCs, motors and drives toward more integrated solutions covering automation, data acquisition, energy management, equipment condition monitoring and digital production.

For aging hot and cold rolling mills, the combination of retaining sound mechanical equipment + upgrading electrical control systems + modernizing automation can provide a practical pathway for extending equipment life and improving production performance.