VDEh-Betriebsforschungsinstitut GmbH, Düsseldorf, Germany:

Sartor M., Dr. Eng., Head of Project, miriam.sartor@bfi.de

Orosz R., Dr. Eng., Head of Project

Reichardt T., Grad. Eng., Chief of Department of Coatings and Tribotechnics

Hoesch Hohenlimburg GmbH, Hagen, Germany:

Hänsch W., Dr. Eng., Chief of Department of Technological

During hot rolling of C–Mn- and Si-containing steels at Hoesch Hohenlimburg form red scale. Even pickling cannot remove the red scale and the resulting stripes can easily be detected and lead to impairments on the surface of the strip. Lab investigations at VDEh-Betriebsforschungsinstitut (BFI) showed that the atmosphere during the transportation of the slab from the descaler to the rolling stand has a significant influence on the red scale formation. Layout of the hot rolling plant at Hoesch Hohenlimburg is shown. Test rolling included processing of a sample heated without oxygen and a sample heated with oxygen-containing atmosphere. Scaled samples, cooled down in different atmospheres) nitrogen, oxygen and water steam), and scale formation for the same conditions itself have been analyzed. It was shown that the most scale forming is situated for oxygen atmosphere (106 g/mm² or 1,2%), while for other cases only 65–72 g/mm² and 0.7–0.8% have been obtained. Slab surface after descaling before first rolling in the duo stand as well as coil surface with red scale have been compared. A scale detection system detected scale blisters on the surface of the slabs in the hot rolling plant which form red scale during rolling.

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