The markets of stainless steels are growing steadily, but differently depending on the period and on the geographical area. They are supplied by an industry which is undergoing significant transformations of structure and production methods. This sector is characterized by a strong competition and worldwide exchanges which lead to reduced conversion margins and price alignment. The properties of stainless steels and the variety of their grades and applications contribute to their further development and competitivity.

Sollac Lorraine is equipped with two bottom blowing converters which are the bottleneck of the steel shop. A dynamic guide based on a temperature measurement of the metal during blowing and an original use of the analysis of the gases coming out of the converter permit tapping immediately at the end of the blowing. The industrial start up of this process in July 2001 has resulted in an increase in converter productivity and efficiency.

This study concerns the analysis of environmental effects on the behaviour under monotonic and cycling loading of alloys based on FeAl and TiAl intermetallic compounds. Special attention is paid to the coupling of environmental and mechanical effects. In both types of loading, the species which is found to operate at ambiant temperature is water vapour. This species plays also a determining role in fatigue crack propagation at elevated temperature. Effects due to oxygen adsorption are also discussed.

The behaviour of dioxin in several arc furnaces was studied in detail in relation with the specifications for various types of organic and inorganic gas. After a pilot plant study has been carried out to know the effect of secondary combustion and rapid cooling on the reduction of dioxin in the arc fumace, ways to lower dioxin below regulation levels were proposed. To understand the reactions, laboratory studies and thermodynamic calculations have been done.

The efficiency of automatic flatness control systems in hot rolling mills is based mainly on the capability of the installed instrumentation to provide accurate flatness measurements, on accurate prediction models, and on the selection of an optimum control concept. BFI, together with Thyssen Krupp Stahl, has recently developed a new topometric flatness measurement device (called TopPlan) and advanced flatness control strategies (providing time delay compensation, systematic analysis of shape errors and exact distribution of shape coefficients to be controlled by actuator sets) that offer advantages over conventional techniques and lead to significant improvements in hot rolling processes and strip shape. The present article aims to demonstrate the principles and advantages of these technologies.

Application of advanced edging equipment in combination with sophisticated automation and control systems is necessary for improving the width accuracy of hot-rolled strip. This paper reviews the existing edger equipment and introduces an important contribution of VAI to this problem : a non-linear automatic width control system (AWC) based on the use of short-stroke cylinders.

The modular VAI-CON system developed by VOEST-ALPINE Industrieanlagenbau (VAI) is a highly effective solution for reducing slag carry-over at converter tapping. It operates automatically and is characterized by long-term availability, high service life and great accuracy. It contributes to a significant reduction of operational and maintenance costs.

Powders obtained by high energy crushing are often easier to compact than conventional polycrystalline powders. In the present work, phase transformations during thermal treatments in high speed steels, prepared by compaction of nanostructured powders obtained by mechanical synthesis, are studied. These transformations and the resulting microstructures are compared to those of conventional steels produced by melting and solidification.

Nippon Steel Corporation started the operation of a dust recycling plant based on technologies of the rotary hearth furnace. The Kimitsu plant has a large 180,000 ton-per-year capacity. New technologies of pellet making, zinc recovery, iron oxide reduction, DRI pellet sintering, etc. are developed and adopted. The dust and sludge are reduced and transformed in almost zinc-free DRI pellets that are strong enough for the BF charge. This plant has solved the problem of the increase in zinc load of the BF when charging dust and sludge.

A new technology for separating and recovering iron and zinc from EAF exhaust gases is proposed. The process is composed of a coke bed filter and a new type of zinc condenser. Iron and slag components in the exhaust gas are collected in the coke bed filter. In this paper, the theoretical background and numerical analysis of the characteristics of the coke bed filter are introduced, and the experimental results concerning the collection of iron and slag components in a bench-scale coke bed filter are reported.

The first industrial twin roll caster for carbon steel strips is under construction on the Nucor site at Crawfordsville. This installation based on the CASTRIP technology developed by BHP and IHI is expected to produce 500 000 tons per year of hot rolled strip with a thickness below 2 mm. In this paper the characteristics of the CASTRIP technology are presented, with reference to the economical aspects and further details on the main breakthroughs that had to be accomplished to improve the efficiency. The twin roll caster technology offers many advantages in terms of production costs, environment and production flexibility over more conventional production routes for carbon strips with a thickness below 2 mm. It is expected that the implementation of the new technology will foster the user demand for ultra thin gauge hot rolled strips.

Classically, the simulation of primary recrystallization and grain growth starts from a theoretical microstructure defined numerically and characterized by a random texture distribution. The results obtained in this way represent well the overall behaviour of the material during annealing, but do not allow to obtain a local description, consistent with reality. In such procedures, a perfect homogeneity is assumed both for microstructure and for texture, which is generally not observed experimentally. For this reason, the authors have proposed in recent years to combine simulation and experimental observations; the calculation starts from the real microstructure characterized by TEM or by OIMTM. The first simulations of this kind carried out have shown that such an approach is feasible and has a great potential. These results are summarized and discussed in this paper. There are limits to this approach, related in particular to the lack of experimental data on the strain energies stored in the grains after deformation and on the energies and mobilities of grain boundaries.

The damaging effect of corrosion-fatigue depends on many parameters. In addition to the influence of the material microstructure, work piece geometry or mechanical loading type, the combined effect of physical-chemical and electrochemical factors has to be considered. After a short presentation of the main parameters and of their effects, the paper concentrates on the outstanding features and the necessary precautions relative to the proper design of corrosion-fatigue test methods. Particular application cases of this approach are then presented.

In spite of its shortcomings, the salt spray test is universally used to characterize the corrosion resistance of zinc based coatings. A working group has tried to improve its reliability by the introduction of a new calibration method of the equipment. The outcome of the work is the definition of a new testing procedure, presently adopted in France for the control of coated products delivered to the automobile industry.

A new bell-less top was installed at Chiba No.6 blast furnace in 1998 for advanced burden distribution control. Reduced scale model experiments were used to develop the rotating chute with stabilizer and the reverse-forward tilting function. Furthermore, an accurate simulator for burden distribution was developed. The results obtained allowed to implement an operational trial of reverse tilting charging. Burden profile and gas distribution could be controlled satisfactorily with this method.

A fast-computing model for crown and flatness in hot strip rolling and plate rolling has been developed based on steady-state elastic-plastic finite element simulations and an elastic buckling analysis. A single, geometry-independent tuning coefficient needs to be identified for each steel grade family. As a result, the model can be efficiently tuned to production mills. Implementation into the set-up environment “CID” of the SOLLAC Méditerranée hot strip mill is presented.

Coatings are widely applied to improve the durability of components. In order to understand how corrosion protection is obtained, the behaviour of coatings in aggressive environments must be characterized. Factors responsible for an increase of the susceptibility to corrosion are indentified and methods available to characterize these factors are reviewed. These are indirect methods as they do not concern the measurement of corrosion rates, nor the study of corrosion mechanisms. They deal with morphology, composition, crystallographic structure and mechanical properties of the coating.

IRIS is a new gate-unit control system, based on the accurate detection of slag carryover during converter tapping. This detection is obtained by analysis of the pictures delivered by an infrared camera. This novel system offers a number of advantages in comparison with conventional electromagnetic systems, as well from the point of view of metallurgy as of productivity. IRIS is now installed at all three converters of voestalpine, but can also equip electric furnaces.

Shredder residue is an unavoidable by-product of the treatment of end of life vehicles and household appliances. NKK has developed a new post-treatment process in which the residue is introduced in a bath of solvent made of hot tar and gives an overflow of plastics and metallic sediments. The recovered plastics can be injected into the blast furnace and the metallic parts recycled in the steel shop. This new process allows a high recycling rate of treated materials.

The generation of ultrasound by pulsed laser and the detection of these waves by interferometry, shortly called laser ultrasonics, presents many advantages for steel applications because it permits the transduction of ultrasonic waves at a significant distance. Nowadays, this technology is well established in the aeronautical field and is beginning to be used in metallurgy and in the steel industry. This paper describes the physical principles and the technological features of laser ultrasonics. Different examples of present and future applications in the steel industry are presented. They concern different fields, the most important are the monitoring of microstructure in real-time and at high temperature and the on-line measurement of thickness.