Innovation provides an edge: New S-6-high process boosts productivity at ThyssenKrupp Acciai Speciali Terni

Innovative "S-6high" rolling technology integrated on strip processing lines is in use at only a handful of stainless steel mills worldwide. ThyssenKrupp Acciai Speciali Terni in Italy is now one of them. Following installation at the beginning of the year and completion of the rampup phase, the new twostand rolling mill is now running at full capacity. It is positioned in the entry zone to the hot strip annealing and pickling line (LAC 10) and, features small diameter, laterally supported work rolls. Thanks to the specific configuration of the stand, cold reductions up to 50% on the incoming black strip can be applied. The particular advantage of this method is that it combines several processing steps in the stainless steel production process and thus amounts the efficency. Tandem cold rolling, hot strip annealing and pickling are normally carried out in separate processes: With the installation of the new rolling mill, these steps are now integrated in the existing LAC 10 line, eliminating the need for cost- and timeintensive intermediate annealing.

In this way, ThyssenKrupp Acciai Speciali Terni has not only significantly consolidated the production process and boosted efficiency, it can now also market a product whose microstructure, mechanical properties and geometric tolerances are virtually the equal of a standard coldrolled strip. This new product, called 2E-Finish (cold rolled, annealed, blasted, pickled, stretch leveled) represents for some applications an attractive lowercost alternative to conventional 2D/2B (cold rolled, annealed, pickled / skin passed) finishes.

Further advantages: Hot strip can be produced in a greater range of sizes and the process chain for cold strip is shortened considerably through the combined rolling and annealing of hot strip. The reduction in hot strip thickness also gives the hot rolling mill greater flexibility, resulting in a notable increase in productivity. Moreover, the S-6high process is capable of producing also cold rolled and annealed coils in 2D finish (cold rolled, annealed, pickled) directly from the LAC10 by a double passage on the line.

"Our customers also profit directly from these technical innovations: The more compact production cycle shortens our delivery times and distinctly improves strip thickness and flatness tolerances," explains Alessandro Segala, head of the Metallurgy and Innovations department at ThyssenKrupp Acciai Speciali Terni. "This 6-Shigh process is the stateoftheart in terms of process development. It has enabled us to significantly strengthen our competitive position."