Outline and Operating Results of the New 3-Roll Block in the Bar Mill of Sumitomo Metals Kokura

by Koichiro Kawakami, Dr. W.-Jürgen Ammerling

Publisher - SUMITOMO METALS (Kokura), Ltd., FRIEDRICH KOCKS GMBH & CO KG

Category - General Novel

Sumitomo Metals Kokura (SMK) is manufacturing specialty steel mainly for the automotive industry in its integrated steel plant based on the blast furnace route. In order to meet recent market demands such as improving quality, reducing cost and securing flexible delivery SMK upgraded its bar mill by introducing the latest development of the 3-roll Reducing & Sizing Block (RSB) technology. The RSB produces a maximum size of 120mm diameter whereas all products are rolled by adopting the “free-size” rolling method. The 3-roll RSB was manufactured by Friedrich Kocks and features the highest rigidity so far. It has been commissioned in August 2009. Design features and processes used in this 3-roll block are described in summary. As a result of the upgrading project, the tolerances along the complete bar length have been improved and so the best bar quality could be achieved. Furthermore, SMK has improved the mill utilization by quick stand changing with stand cars and adopting the “free-size” rolling of finely graded bar diameters from a minimum number of feeders out of the intermediate mill line. Moreover, the RSB with some other minor accompanying modifications was not only leading to a better bar quality but also, through various operational improvements, higher cost performance.

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