Influence of disturbances in temper mills on work roll surface reproduction onto temper-rolled strips

Abstract

The article considers how the disturbing factor of equipment components in temper mills, the thickness variation of a substrate, the instability of strip tension, backup roll runout, and other factors influence the reproduction coefficient of surface microgeometry of work rolls onto the temper-rolled strip, and consequently, the variation of microgeometry parameters of strip surface on its separate sections. These fluctuations in the reproduction coefficient are qualitatively estimated, with their percentage contribution to the total disturbing factor in the temper-rolling process being established. We demonstrate that the backup roll runout exerts the most significant influence on the instability of the reproduction coefficient, which accounts for 38 to 45%. The findings are illustrated using the example of temper mill 1700 at Magnitogorsk Iron and Steel Works (MMK, Magnitogorsk, Russia), which indicates that at low levels of all disturbing factors, the fluctuation in the parameter Ra of the temper-rolled strip is 5.8%, reaching 9% at higher levels.