Schafer & Urbach GmbH (Ratingen, Germany)

Pawlitzki P. Mag. Eng. Pawlitzki.Peter@schaefer-urbach.com

Rehbein R. Mag. Eng.

Primary and secondary scale is forming during slab or billet reheating in pre-rolling furnaces and during consequent rolling, as a result of air oxidation. This scale has negative effect on surface quality of rolled material, therefore it has to be removed. Hydromechanical descaling units equipped with high-pressure pumps are used for this purpose. Different types of pumps for descaling units — piston-type and centrifugal pumps — are compared, as well as different descaling methods using such pumps. The paper presents the concept of desca ling units with high-pressure accumulators and without them. Potential of power-efficient and resource-saving process is demonstrated. It is shown that using high-pressure accumulator helps to achieve power saving about 72%. Required power consumption for descaling at a hot strip rolling mill can be decreased substantially via usage of descaling systems with high-pressure accumulators. Industrial putting-into-practice of descaling units with high-pressure accumulator and lo wering of descaling pressure by 10 bars has been experienced during modernization of the existing descaling unit at ThyssenKrupp Steel Europe AG works and resulted in improvement of processing quality.