To control the generation of dust in a steelmaking reactor, it is necessary to understand the underlying physical mechanisms. An experimental device has been developed to study the main emission mechanism, i.e. the projections from bursting bubbles. We visualized the burst on liquid steel and quantified the subsequent emission. The chemical evolution inside the fume exhaust system is simulated by thermodynamic calculations : the key parameters for controlling dust mineralogy are the Fe/Zn ratio, the oxygen activity (p$_{{\rm CO_2}}$/p$_{{\rm CO}}$) and the temperature evolution.

Thanks to many technological developments, modern Steckel mills are not only characterized by increased capacities and extended product ranges, but can also deliver plates in addition to hot-rolled strip. Some recent examples of supplies by VOEST-ALPINE Industrieanalgenbau (VAI) show possible Steckel configurations and introduce the innovative solutions developed at these occasions. These examples demonstrate the flexibility and economical efficiency of this technology.

Poly(vinylidene fluoride) (PVDF) thin films were subjected to tensile tests in plane strain over the temperature range from 65 to 115°C. At different elongation velocities using video real stress and strain, it was observed that, under such strain regimes, the neck-in starts perpendicular to the tensile axis and propagates towards the sample ends. The propagation kinetics was carefully recorded during the tensile tests. It was shown with simple hypotheses, that essential plasticity equations of the material can be determined via this method in terms of local effective stress (σeff) as a function of local effective strain (εeff) for every investigated temperature. The X-rays diffraction shows that the stretching of the sample of PVDF at a temperature lower than 72°C causes the transition from phase II to phase I.

The coupling effects between mechanics and corrosion which are involved during corrosion-fatigue of metallic materials are analyzed through significant examples. Quantitative approaches for crack initiation and crack propagation are given and discussed in terms of micromechanisms. The introduction of localized corrosion- deformation interactions in damage modellings is proposed and further trends for numerical simulations are introduced.

The rate of air oxidation towards 1,000°C of the Si3N4-bonded silicon carbide refractory is low. It is found that the porous nitride-bonding phase oxidizes mainly and that the SiC oxidation is negligible. The decrease of specific surface area, due to the growing of a dense silica layer, induces much slower kinetics.

A new method for controlling the BOF process is proposed thatinvolves the use of an original in blow heterogeneous sampler and adedicated laser analytical method. The aim is to deliver a fast andcomprehensive analysis of steel and slag collected by the heterogeneous-samplings. Combined with a metallurgical model, the dataobtained with the heterogeneous samples make it possible to dynamicallyassess the refining progress in order to allow a safe directtapping practice.

The main components of the Castrip facility at Nucor are presented and the specific features of the twin-roll casting are highlighted with reference to conventional and thin slab casting.Nucor expected in February 2005 a monthly production of 25,000 tons of strips with an average thickness of 1.4 mm and a minimum thickness of 0.84 mm. Most products are utilized in construction application as light gauge hot rolled low carbon steel grades.
Nucor is now in the planning stages for a second Castrip facility in the United States and is exploring opportunities for utilizing the technology internationally through joint ventures.

The steel industry in Europe has demonstrated a major commitment to reduce the environmental burden of its activities. The investments in environmental protection can be estimated between 5 and 15 % of the total capital expenditures to improve the individual operations. These efforts are strengthened by the technological evolution of the steel making sector and by an increase of the recycling route. The new development of viable techniques is still required to further reduce the emissions to the air, mainly from sinter plants and to decrease the amount of waste. Finally, it will become necessary in the future to fundamentally rethink the use of reducing agents to reduce the CO2 emissions.

The hydrodynamics in an electrolysis pilot-cell has beenmodelled with the aim of upscaling the direct iron productionprocess based on the alkaline electrolysis of an iron oxidesuspension. Two dispersed phase flow involved in this threephaseprocess have been evaluated: the solid and the gasphase hydrodynamics.The suspension flow characteristics areevaluated from existing litterature, and available correlationsare applied to the case under study. The minimum velocityrequired for transportation of finely ground iron oxide alongthe cathode surface is fairly low, in the laminar regime,corresponding to minimum pressure drop.The behaviour ofthe oxygen phase produced on the anode is evaluated in attwo scales. First, the trajectory of a single bubble sliding onthe anode is depicted, predicting possible rising or draggingof the bubbles as a function of its diameter. The gas-phasepattern is then studied from litterature results for gas-liquidflow in pipes. A separation of the gas phase from the liquidis predicted, the lightest phase being in contact with theupper part of the cell. Obtained results confirm the potentialof the selected design for transportation of particles and gasrecovery with low energy consumption.

In this article, we briefly recall the physical mechanisms at the origin of the Barkhausen effect in ferromagnetic mediums and the thermoelectric power in conductor metals. We then present, for each of these phenomena, the measurement principles and their sensitivity to the microstructural state, notably in the case of precipitation phenomena and in the ones linked to plastic deformation. Finally, in the case of the formation of precipitates in an iron-based alloy, we show the complementarity of both techniques.

The end blow manganese behavior in BOF process wasassessed through analysis of an industrial data base.
The available literature suggests that the main operationalfactors to influence the end blow manganese behavior inBOF are: manganese input, slag volume, oxidation level andtemperature. The large extension of the industrial data basehas made possible to separate the influence for each factor.Then correlations between end blow manganese and thesefactors have been obtained.

This paper deals with the influence of thermal strains/stresses causedby braking on the fatigue life of cast nodular iron disc brakes forrailway vehicles. The thermal stresses have been experimentallyderived and the durability has been assessed for a breaking loadspectrum comprising 6000 stop brakings from 200 km/h, 3000 stopbrakings from 160 km/h, 1500 stop brakings from 120 km/h and30000 usual brakings periods slowing down from 90 km/h.The fatigue critical areas have been identified and a redesign of thediscs made it possible to afford the requested service life of3×106 km.

Environmental emissions constraints have led manufacturersto improve their low NOx recuperative burners. The developmentby Tenova of the FlexyTech® Flameless burners withlow NOx emissions, even below the present “Best AvailableTechnology” limit of 40 ppm at 3%O2 with furnace temperature1250°C, air preheat 450°C, is described. The results achievedduring the R&D programme have been also improved inthe industrial installations. Some details and performances ofthe recent furnaces equipped with such burners are provided.

The Clean Development Mechanism Project elaboration is reviewed,considering every step from the project design document conception,through validation, the approval by the national authorities andthe verification process.The whole development is pioneered by CST ArcelorMittal Brasil,aiming at carbon credits generation and GHG emission reduction.An associated objective is the promotion of sustainable development.The potential of carbon credits generation is estimated to be440,263 tons of CO2 over a CDM project period of 10 years.

Accretion on the lining of the blast furnace results in a harmful effect on burdendescent, which also has a negative effect on energy balance. This eventually leads toincreased CO2emission. We examined which blast furnace zones were significantly affected by thethickness of the accretion layer and how this affects the blast furnace gas streamrelations. Using a heat transfer model, the samples taken from the accretion andstatistical analysis of the typical operating parameters of the blast furnace, amathematical model was created in order to determine the thickness of blast furnace shaftaccretion and its effect on gas utilization.

In view of the weight reduction strategies required and increasingly implemented by the automobile industry, growing importance is being attached not only to the materials but also the forming methods used. Forming processes using hydraulic media in particular offer the potential to produce more complex parts economically while optimizing component properties. The tube hydroforming (IHU) and hydromechanical sheet forming (AHU) processes are ideally suited for the production of automotive components in line with these requirements.

The properties of the well known enhanced steel 12 Cr Mo9-10 are compared with those of the most recent generation of modified CrMoV steels who are characterized by the addition of vanadium. The comparison concerns the base material properties before and after heat treatment, as well as the influence of hot forming and welding with and without step cooling. Creep data are also reported.

To optimize the process and improve the degree of reduction, a two-stage experiment wasdesigned. It was carried out in a micro-fluidized bed. It is operated as a differentialreactor to ensure every particle in the micro-fluidized bed is at equal temperature,concentration and residence time. The experiment used iron ore powder from Yangdi. Thereducing gas and temperature in the pre-reduction stage were, respectively, pure CO and625 °C. In the final reduction stage, the temperature and reducing gas were, respectively,800 °C and pure CO. The residence time was between 10 min and 60 min. In addition to theexperiment, a microscopic technique was also carried out. The test shows a significantinfluence of the temperature and residence time of the two-step experiment on the finalreduction degree.

The main purpose of ArcelorMittal Tubarao skin pass is to improvethe flatness in thin gauges hot rolled strips. Since the start-up in2002 several actions have been implemented and a consistentevolution of quality and process control has been reached:
The philosophy of production scheduling along the rolls campaignto minimize the effect of roll wear;
The definition of optimum target elongations to keep as constantas possible the roll forces and avoid roll bending changes;
The automation of bending forces control according tocharacteristics of the strip and the rolls.