A study of the installation and operation of flatness measuring systems in cold-rolling mills
Strip flatness is measured to improve quality and efficiency at cold-rolling mills. Generally, tensile stresses are measured, as these are assumed to be proportional to strip length variance. When rolling steel and even non-ferrous metals, length distribution determined across the strip width differs before and after coiling, without any additional deformation caused by rolling. To investigate process-inherent measurement errors as a possible cause, local interference stresses, disproportionate to the length distribution, were induced. These subsided within half the strip width. But when the stresses were induced asymmetrically, there was no balancing out for up to 8 times the band width. Plastic strip deformation outside the rolling gap may play a part and was also studied. Changes to strip flatness of between 100 microns/m and 300 microns/m occurred on deflection or coiling outside the rolling gap. These, however, are not cumulative in one direction. The locally occurring plastic strip elongations are not solely attributable to tensile and bending stresses applied. It is supposed that tensile stresses necessary for plastic elongation are reduced as a result of increased internal stresses within the coiled strips.
Bibliographic Reference: EUR 13338 DE (1991) 78 pp., FS, ECU 7.50
ISBN: ISBN 92-826-2405-6
Record Number: 199110621 / Last updated on: 1994-12-02
Original language: de
Available languages: de