Primetals Technologies Austria (Linz, Austria):

K. Krimpelstätter, Dr., Head of Technology and Innovation for Hot and Cold Rolling
I. Maeno, Senior Vice President, Hot Rolling, Cold Rolling and Processing Europe
M. Bergmann, Dr., Expert Cold Rolling
G. Keintzel, Senior Expert Mechatronics and Sensoric
E-mail (common): contact@primetals.com

An important tool to increase the efficiency of the rolling process on existing mills is to reduce the diameter of the work rolls, especially in the middle stands of the tandem cold rolling mill. This article presents a historical overview of the change in the diameter of work rolls when rolling strong and thin steel strips, as well as description of two new solutions for production of AHSS steels. Another approach that facilitates the rolling of high-strength steels is to improve and optimize the lubrication of the roll gap. This is especially important when rolling strong and / or thin steel strips. The new technology for lubricating the roll gap allows flexible adaptation of the thickness of the oil film (in the roll gap) regardless of the rolling speed and thereby provides significant advantages when rolling AHSS steels. Nevertheless, the growing trend in production of stronger and thinner strip steels increases the risk of unwanted vibrations of the rolling mill. To eliminate this risk, a vibration suppression solution has been developed that ensures high performance of the AHSS steel production process. The system was tested in real industrial conditions, since its functionality could only be tested on the existing cold rolling mill, in which vibrations of the 3rd octave occur. A partner was found for NLMK, a leading steel producer in Russia, who showed interest in the system and was ready to accept the risks and challenges associated with such innovative solution. Based on the results obtained and the experience gained from the first industrial tests, the system was improved, and as a result, the design of the hydraulic unit was optimized; improved filtering and control algorithms (in cooperation with the university in Linz); the new high-performance automated system provides a controller sampling rate of 20 kHz.