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.

Over the past few years several technical efforts have been focused on continuous improvement of quench and tempered product at ArcelorMittal Burns Harbor plate mill facility with particular attention being given to optimization of the flatness of quenched product. Incremental improvement in quench line equipment and practices is being aided by computer-based modelling tools and specialized instrumentation. The paper describes the development of different tools used to control flatness after quench and tempering units. The detailed description of a 3D model designed to predict distortion such as edge waves, center buckles, longbows and crossbows during quenching is presented. The model developed with Abaqus is able to predict the evolution of plate temperature, thermal stresses, strains, and distortions during cooling. The water cooling system is represented by top and bottom movable surfaces where a heat flux depending on width, length and temperature is applied. The effect of phase transformation is approximated by a variation of the plate thermal expansion coefficient.

Several parts of degraded organ pipes belonging to some organs produced in different periods (from the 18th to 20th century) and from different Italian geographical areas have been examined and investigated in order to identify the possible causes of the degradation phenomena. An analysis through DSC-DTA measurements has been performed to define the crystallographic transformation of the studied alloys and a metallographic analysis has been realized to point out the microstructural characteristics. The morphological analysis has been improved by SEM equipped with an EDS device which permits a quantitative chemical characterization of the intact zones and of the degraded ones. The presence of chlorides has been identified as the starting factor of the degradation phenomena.

Against the background of the several years lasting slump in the real price of stainless steels, different ways to reduce the production costs of these steels are analyzed. They consist in innovative technologies, some of which are already applied and others are still waiting for confirmation at the industrial scale. The emphasis is put on developments made by Voest-Alpine Industrieanlagenbau (VAI).

La première étape de ce travail est le calcul ab initio des énergies de mise en solution et de mélange du chrome et du fer. Nous confirmons les résultats ab initio proposés précédemment. Nous utilisons cette même méthodologie afin de calculer les énergies de surface du fer et du chrome dans les orientations (100), (110), (111) et (211). Contrairement aux extrapolations depuis les mesures expérimentales aux hautes températures, ces calculs montrent que les énergies de surface du chrome sont supérieures à celles du fer. Nous calculons également l’énergie de ségrégation d’impureté du chrome dans le fer (100) qui est endothermique. Enfin, nous proposons un modèle énergétique ajusté sur les calculs ab initio. À partir de ce modèle, nous calculons des isothermes de ségrégation et montrons que les surfaces de l’alliage sont toujours appauvries en chrome du fait de la grande différence d’énergie de surface entre les deux éléments qui a été révélée par les calculs ab initio.

To maximize furnace campaigns and to minimize production downtimesthrough short lining times, the entire integral blast furnacearea, including the auxiliary units, has to be theoretically partitioned.The evolution of measures for extending furnace life is in conjunctionwith the investigation and understanding of the in some respectsvery complicated wear mechanisms and their causes. Of mostimportance are the constructional, material and process engineeringmeasures to reduce wear and the measuring instrumentation forearly detection and progress monitoring of wear.

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.

A new technique for automatic assessment of centre line segregationbased on image analysis is presented. This innovative tool candetect both centre line segregation and centre line cracks from digitalizedsulphur prints giving an objective result. A data base containingprocess data from the caster and the new index for segregationmeasurement have been created. First analyses of this data base bydata mining tools have been performed showing very promisingresults.