The project participants at the inauguration (Photo: thyssenkrupp steel)
On September 26, thyssenkrupp Steel, the German steel industry leader, marked a significant milestone by rolling its first coil on the newly installed 2-stand reversing cold mill provided by Primetals Technologies. This state-of-the-art mill, integral to the steel giant's future endeavors, was officially unveiled during a celebratory event at the Bochum plant in Germany on October 30. The inauguration witnessed addresses from prominent figures, including Heike Denecke-Arnold, Chief Operations Officer at thyssenkrupp Steel, and Thomas Eiskirch, the Mayor of Bochum.
“thyssenkrupp Steel wants to significantly strengthen its capabilities in high-strength steels and electromobility so we can differentiate ourselves even more consistently through the quality of our products,” said Heike Denecke-Arnold. “For example, with even thinner and stronger sheets, we want to further increase the energy efficiency and therefore the range of electric motors.”
The project presented its share of challenges for the Primetals Technologies team, with pandemic-related and Ukraine conflict-induced disruptions affecting supply chains and delivery schedules. However, through dedicated project management efforts and transparent communication, all planned milestones were successfully achieved. The utilization of comprehensive 3D models facilitated smooth and efficient pre-assembly, enabling the mill's complete construction, including its electrical and automation systems, within a mere six months.
Thinner and Lighter
The double reversing cold mill, with its versatile back-and-forth operation, boasts the capability to roll exceptionally thin strips with an end-product thickness as fine as 0.2 millimeters, thinner than a fingernail. On the flip side, it can also handle heavier gauges, catering to products demanding the highest levels of strength. This extraordinary achievement in strip dimensions is made possible by highly skilled operators supported by advanced automation solutions.
“We are very excited to support thyssenkrupp Steel on its endeavor to further expand in the market for silicon steel,” said Hans-Jürgen Zeiher, Head of Electrics and Automation at Primetals Technologies. “The need for advanced high-strength steel grades used in electrical vehicles is projected to rise to extremely high levels over the coming decades. This mill ensures that thyssenkrupp Steel is well-prepared to deliver thinner and lighter steel of very high quality – exactly the type of steel needed in electrical vehicles.”
Pioneering Silicon Steel Cold Rolling
Several factors influenced thyssenkrupp Steel's choice of Primetals Technologies as its supplier, with strong references in Asia being a pivotal consideration. Primetals Technologies, the market leader in silicon steel cold rolling, boasts a 90 percent market share in Asia. Another key factor is the unique Hyper UCM technology's features, which enable operators to flexibly influence strip edges, a common area for crack occurrence.
A powerful payoff reel and strip heating system, in conjunction with Primetals Technologies' Minimum Quantity Lubrication (MQL) system, ensures a seamless operation at the first rolling pass. The Hyper UCM's foundation lies in an optimized combination of roll diameters for work rolls and intermediate rolls, allowing for the use of smaller-diameter work rolls—an essential success factor for achieving incredibly thin final gauges. Furthermore, robust tension reels and various lubrication technologies outperform traditional cold mills in achieving higher reduction levels.
Enhancing the Rolling Process
Primetals Technologies supplied all mechanical equipment, along with electrical and automation systems for the mill, and managed installation and implementation. The automation solution plays a pivotal role in enabling the production of extremely thin and strong steel grades. Features of the Level 2 automation system include compensation algorithms for coiler runout, roll eccentricity, and main drive utilization. Additionally, established process models for roll gap and roll and strip temperatures are integrated to support control over the entire rolling process and settings related to material flatness. The Contactless Shape Monitor, a solution from Primetals Technologies for measuring flatness, is a vital component of the advanced flatness control system.
Three Major Projects with thyssenkrupp Steel
In 2021, thyssenkrupp Steel placed a significant order with Primetals Technologies for the reversing cold mill, a hot strip mill, and two continuous casters. All these projects are scheduled for completion by 2025. With an annual production volume of approximately 11 million tons of crude steel, thyssenkrupp Steel employs approximately 26,000 individuals worldwide. The company has set ambitious goals to produce five million tons of CO₂-neutral steel annually by 2030 and aims for complete climate neutrality in its production by no later than 2045.