The reasons of the success or phaseout of an industrial process remain mysterious. The history of the Perrin process allows to analyze this problem. After having described the process and the physical-chemical mechanisms underlying it, the author presents the good results obtained for the dephosphorization and the deoxidation of liquid steel and the problems which had to be solved in the case of desulphurization. Different aspects of the application of the process are discussed and different views on its adoption by steel producers are compared.

For years, the iron and steel industry has been in search of new processes for an efficient production of virgin steel as well as for the recycling of its by-products, especially for those containing zinc. Considering these objectives, Paul Wurth S.A., in cooperation with ProfilARBED, has developed a process using the multiple-hearth furnace and coal fines as the reductant and main energy source. A trial plant with a capacity of 2 t/h was built and has been operated for more than one year at the ProfilARBED Belval site. This paper reports on the trial campaigns, which have given most promising results.

At the integrated works of the Indian steelproducer Jindal Vijayanagar Steel Ltd, the first of the two planned COREX® units is in operation since August 1999. This ironmaking plant, which was designed and erected by VOEST-ALPINE Industrieanlagenbau (VAI), operates since its start-up at a production level significantly exceeding the design capacity. The paper describes the process sequence, the materials used and the operating results. The second unit of the same type is planned to start-up during the second quarter of 2001.

Irsid and DCPR from Nancy present an investigation on the generation and the abatement of organic molecules in the flue gas of an electric arc furnace. Investigated in detail are the environmental cleanliness of scrap, the mixed pyrolysis and combustion that generates these molecules, the solution to destroy them completely that a perfect post-combustion offers, as demonstrated in the laboratory and as extrapolated for industrial scale, and the condensation of dioxines in the flue gas collection system.

CRM has developed a mathematical model of the sintering process aiming to optimize the latter in terms of both performances and environmental impact. The model is able to simulate conventional sintering as well as original layouts like selective waste gas recycling with integrated desulphurization or steam injection at the sinter bed surface. The results (in particular CO and SO2 emission profiles) have been validated experimentally and also at the industrial scale.

The demand for improvements in surface quality and increased productivity in industrial cold metal rolling requires a good understanding of lubrication mechanisms. The limitations are due to boundary friction, controlled by the physico-chemistry of lubricant additives. The phenomena are complex and require a simplified approach. Consequently, a new method was developed by using an UHV tribometer associated with surface analytical tools to simulate the molecule chemical reactivity toward surfaces.

Ancient artisans conferred special colourings to their metal artefacts by particular techniques, which went lost in later centuries. They were also able to give to copper based alloys the appearance of precious metals. The author presents ancient examples of coloured metals and alloys, identified by scientific methods and discusses the problem of recognizing various surface treatments on archaeological objects.

In order to extend the RH lower vessel campaign life and to recycle used retractories, MgO-C bricks were applied for the RH lower vessel. As a result, the campaign life of the lower vessel has been extended by approximately 15 % , compared with magnesia- chromite bricks normally used. It was further ensured that it was possible to refine ultra-low carbon steel under these conditions.

The new casting-rolling plant of Thyssen Krupp Stahl AG is in operation since April 1999. Differences in comparison with other CSP plants are described. The production results at this time are explained together with the range of steel grades and the achieved dimensions. Differences with respect to conventional hot rolled strip are shown in surface quality as well as in mechanical properties and in dimensional tolerances.

The twin cathode technology by Danieli is the new generation of DC superpower EAF. This design concept allows the utilization of reduced diameter standard electrodes and low density currents compared to single electrode DC or standard AC EAF of the same power. The operative results of this technology are shown at Hylsa Aceros Planos Mexico.

A three-dimensional cellular automaton-finite element model has been developed over the past five years for the prediction of macrostructures formed in casting. The present article briefly summarizes the growth algorithm of the model. Applications are then given for the prediction of the grain structure formed in a directionally solidified turbine blade produced by investment casting, a continuously cast cylinder and a near-net shape steel sheet obtained by twin-roll casting.

In order to achieve comparatively constant BOF process data, a radar measurement equipment was installed at the two 185-t vessels at the Dillinger Hütte steelplant. The level of liquid steel in the converter is easily measured for every heat with a radar unit. With this installation, the distance between the tip of the oxygen blowing lance and the steel surface can be adjusted in accordance to process conditions. As a result, metallurgical and technological improvements were achieved, e.g. the Fe-content of the slag was reduced and the lime consumption could be lowered as well. A more uniform lining wear can be observed and the life of lance tips is increased.

As part of the modernization project of C.-S. Chertal in view of the increase of its annual production to 3.5 Mt, the RH degassing unit has been revamped in order to produce 1 Mt of ultra-low carbon steel. Three goals had to be reached : avoid the raise of tapping temperature in the BOF - RH - CC4 route, reach 100% of heats with a carbon under 30 ppm in the tundish, achieve a high level of availability of the degasser. We present here the technical solutions and operating modifications chosen.

The optimized overall control system developed by VAI for sinter plants integrates mathematical models and artificial intelligence. It features a process information system and a collection of on-line process models. One group of models is used for the control of sinter productivity and the other group for the control of sinter quality. The setpoints calculated in that way control the sinter plant operation directly. The different modules included in the system are described in the case of the Wuhan Iron and Steel Co. sinter plant in China.

The flow between rough surfaces in sliding motion with contacts has been analyzed through the volume averaging method for different geometries of surfaces, including the self-affine geometry encountered in cold rolling. In this paper, we simply give an overview of main results. An average flow model is derived, in which the influence of roughness is taken into account through effective transport tensors called "flow factors" . The flow factors have been determined for various deterministic (sinusoidal) and random roughness distributions.

Several innovations in the casting of steel into ingots have found their full application in continuous casting. Bessemer made significant contributions in this area, but the decisive developments were made by others between 1920 and 1950 in the USA, England, Germany, etc. After the casting of billets became a well established process, new developments allowed to apply the process to slab casting and a high degree of performance is reached now. The direct casting of thin products, first attempted by Bessemer, is just becoming industrial reality.

Using an IF-steel, the application of ferritic rolling in the thin slab direct rolling technology has been studied with the objective of producing thin hot rolled strip with good deep-drawing properties. The effect of the main processing parameters has been simulated in the case of the production of two types of finished products: "soft" hot strip (completely recrystallized during coiling), "hard" strip (obtained with low finishing and coiling temperatures and subsequently annealed).

The chemisorption of cold rolling oil additives on steel and aluminium surfaces is studied with a mass spectrometry technique, ToF-SIMS. Preliminary experiments underline adsorption competition, and thermal threshold for desorption or decomposition. This results fit well with experimental cold rolling results.

When argon gas is injected into the caster moulds, the similarity between water models and actual casting conditions comes into question. This is why LTV decided to investigate new technologies. The paper presents these technologies and discusses the programme results. PIV is a powerful laser-based technology that was used on the LTV 0.4 and full-scale water models to determine water velocities. MFC sensors are magnetic sensors that were installed on the LTV Cleveland-East 2-strand slab caster to measure actual liquid steel velocities. In addition, nails boards, X-ray and SEM analyses were extensively used to determine molten slag layer thickness profiles during casting, gas bubbles/pinholes location and steel defect composition, respectively.

This paper addresses several experimental techniques, which have been developed and validated with the aim of assessing the mechanical conditions of service-exposed primary plant components, particularly from the point of view of fracture toughness. Such techniques are based on the use of specimens of small or even miniaturized size, as an alternative to the "conventional" methodologies described by commonly used test standards.