Based on a model of microstructure evolution, an appropriate rolling schedule has been worked out to produce ultrafine grained steel (2 to 5 μm) on the hot strip mill. This rolling schedule is characterized by a large reduction in the finishers followed by strong cooling. Implementing such a rolling schedule on a conventional HSM raises major problems: increased rolling torque and force, lowered crown and shape control, disturbed looper control, accelerated roll damage, increased slip between strip and roll, insufficient cooling efficiency. These problems have been solved on the new Nakayama HSM by introducing innovative processes such as: single roll drive with different diameter and a new CVC, curtain wall cooling in the finisher, low inertia hydraulic looper, new high-speed steel rolls with solid lubrication.

The hot strip mill of Arcelor in Fos has been revamped between February 2001 and July 2002. Positive/negative (±200 tons per side) bending actuators were installed on the four first stands of the finisher. This investment made it possible to further improve the geometry of the products (crown and thickness control), as well as the reliability and productivity of the HSM.

A new on-line guidance tool has been implemented to help the mill operator with the achievement of a thickness performance that meets the ever more stringent requirements for DWI material. The tool makes it possible to analyse the causes of thickness defects that are originated by the HSM or by the tandem mill.

The instrumented bars designed and patented by Arcelor Research enable precise calibration of the actuators (roll-gap, transversal and longitudinal tilting and back-up rolls) of levellers. The calibration procedure requires to stop the cut-to-length line for 30 minutes to calibrate the leveller, if no major mechanical operation is necessary. The measurement device will guarantee the pre-setting validity and the longevity of the leveller.

The coating of thirty-four industrial galvanized samples from four different lines have been characterized by selective stripping and ICP analysis. It is shown that this analytical procedure gives consistent results. The free Al in the coating is always lower than the effective Al in the pot. This is explained by its diffusion after wiping. The Al picked up in the pot is then always lower than the Al tied up on a solidified and cold product. The difference depends on the sheet thickness which affects the cooling time.

EU regulations to be proclaimed will insist on product life cycle, Health-Safety-Environment issues and they will further enforce new ecotaxes. Anticipating these demands would afford Steel a competitive advantage and would further improve its image. The objectives of coated steel products, both in terms of process and properties are presented. The new developments of high performance steel surfaces are highlighted.

Slag splashing is a way of maintaining converters lining, started at the Fos steel plant in December 2003. Systematic slag splashing on converters lining, by nitrogen injection with the top lance, after tapping, protects refractory. The aim of the project is to disconnect the two converters, from the refractory point of view, and to reach a refractory lining lifetime of 5,000 heats.

Led by increasing stainless steel demands worldwide, Avesta Polarit Tornio, now Outokumpu Stainless Tornio, decided to extend its slab production capacity from 650,000 to 1.65 million tons per year of cast products. To supply 1.0 million tons of additional slabs, a complete new steel plant was successfully started up in September 2002. The process route includes a 140 MVA electric arc furnace, a 150 tons AOD, a twin ladle furnace and the world most advanced continuous casting machine. Technological highlights together with operational results are presented.