Siemens announces systems for Strip Cooling in Hot Rolling Mills

May 18, 2007 - Siemens Metals Technologies is now offering rolling mill operators a complete package of solutions for strip cooling in hot rolling mills. “Microstructure Target Cooling” includes a process model, automation and closed-loop control systems as well as mechanical components such as various cooling valves. The process model enables precise calculation and control of phase transformation in the steel and thus reliable and efficient production of modern materials such as multiphase steels or special deep drawing steel grades. Deviations from the specified cooling curve are compensated within just 200 milliseconds. The Siemens cooling valves are characterized by their well-defined switching times and a large bandwidth of available cooling capacity. This means that high-quality steel grades can be produced even with short cooling sections.

The cooling of hot rolled strip is a process step which is crucial for the quality of the steel that is produced. The cooling curve has a major influence on the mechanical properties of the steel. With the help of the Siemens process model - which is based on a thermodynamic description of the cooling process and in particular takes into account Gibbs' enthalpy for phase transformation of the steel - in combination with a model-predictive control system, the entire cooling curve can be controlled along the line. For its entire range of products, the rolling mill operator is thus able to keep a comprehensive control of the microstructure changes caused by phase transformation during the cooling process. Any deviations from the setpoints are corrected within 200 milliseconds. This not only ensures constant quality along the whole strip but also enables efficient and reliable manufacture of multiphase steels. Specific properties of the material, for example in the case of deep drawing steel grades, can also be specified precisely. Moreover, the strip cooling model increases the flexibility of the rolling mill: it is possible to switch over production between different types of steel whenever the situation demands and new steel grades can be included in production without altering software or model parameters.

The Microstructure Target Cooling solution which belongs to the Siroll family of products for rolling mills also includes mechanical components such as cooling valves for diverse applications. In addition to standard valves with cooling rates of up to 1.5 MW/m2, Siemens Metals Technologies supplies “turbo-cooling” valves with cooling rates of up to 2 MW/m2 and an intensive cooling system that enables the dissipation of more than 4.5 MW/m2 of heat. Well-defined switching times for the valves – less than one second in the case of “quick switch” valves – ensure precise control of the amount of water everywhere on the strip. The combination of high cooling rates and short switching times enables the production of high-quality steel grades even in hot rolling mills with short cooling sections. This is especially advantageous if plant operators cannot or do not want to change the built structures when modernizing their installations.

Metals Technologies (MT), a division of the Siemens Industrial Solutions and Services (I&S) Group, is one of the world's leading engineering and plant-building companies for the iron and steel industry as well as for the flat-rolling sector of the aluminum industry and for open-cast mining. MT, which was created from the integration of Voest-Alpine Industrieanlagenbau, Linz/Austria, plus the electrical engineering product business and automation solutions of Siemens, provides a comprehensive range of supplies and services for all related technological processes and integrated automation solutions for the entire life-cycle of metallurgical plants.

The Siemens Industrial Solutions and Services Group (I&S) is the integrator of systems and solutions for industrial and infrastructure facilities and global service provider for the plant and projects business covering planning, installation, operation and the entire life cycle. I&S uses its own products and systems and process technologies in order to enhance productivity and improve competitiveness of companies in the sectors of metallurgy, water treatment, pulp and paper, oil and gas, marine engineering, open-cast mining, airport logistics, postal automation, intelligent traffic systems and industrial services. In fiscal 2006 (to September 30) I&S employed a total of 36,200 people worldwide and achieved total sales of EUR 8.819 billion, according to U.S. GAAP.