The acoustic near field method consists in studying the alteration of the resonance curve of a horn whose tip, the probe, is immersed in the sample. The operating mode in a medium in which strong variations of the rheological properties take place, is modelled for two horn shapes, one with a conical probe, the second one with a stepped cylindrical probe. The experimental curves obtained during the cement setting prove the validity of the simulations. The sensitivity of the horn to a given step of the setting is achieved by adjusting the probe shape.

Deux grandes classes de procédés ont été employées par les forgerons d’aciers dès lepremier millénaire av. J.-C. A partir de deux exemples typiques nous montrons commentl’interprétation des examens métallographiques avec des outils modernes tels que MEB etMEBFEG permet de reconstituer ces techniques. Un échantillon de l’époque mérovingienneillustre la fabrication de lames figurées par multiples opérations desoudage puis forgeage. Un échantillon de wootz prélevé dans une lame du XVIIIesiècle illustre le forgeage du fameux acier fondu de Damas.

In Europe, like elsewhere, the share of steel produced by electric arc furnaces from scrap increases. As the amount of internal scrap has decreased considerably, the steel plants recycle more and more collected obsolete and capital scrap. This source of iron has increased rapidly and will continue to increase. In spite of that, some plants may have to include in their EAF charge prereduced iron coming from countries where natural gas is available at low cost.

Carmakers face ever more frequently the phenomenon of spring-back after stamping, especially with new high strength steels (HSS and VHSS). Renault and Arcelor have been working together for many years on the formability and spring-back of VHSS. Recently, they aimed at establishing a method to optimize die shape in order to compensate for the spring-back after stamping. A method, named “Outifo” has been developed in order to obtain by simulation, from the initial CADs of the part and its referential stamped die, a CAD of a die with a modified shape. This allows the real stamping part, after forming and spring-back, to recover as closely as possible the geometry of the theoretical part defined by the designer.

Energy efficiency in BOF process is related to hot metal and scrapratio and thus to production capacity potential and specific CO2emissions. A thermal balance in the fume system, using a selectedmetrology, can be calculated dynamically and provides a valuabletool for investigating the process parameters that are relevant foroptimizing and controlling energy efficiency. The method and firstresults are presented.

Statistical methods have been used to analyze the thickness variations in coils of packaging steel. A sampling procedure has been defined in order to characterize the thickness variations in length and width directions for a given coil and from coil to coil. The analysis has allowed to evaluate the respective contribution of the various sources of scatter in relation with the production sequence and to define a strategy for the improvement of the results in this area.

For the production of steel with an EAF (especially, also, for stainless steel, as shown at CORUS Engineering Steels in Stocksbridge), the RCB system of VAI FUCHS (Refining Combined Burner) represents an important step forward, in many respects, for the injection of oxygen. The constitution of the system, its working mode and its advantages are described. This innovative solution is already applied in the case of quite a number of furnaces.

For today's investments, quick pay-back is becoming more important than ever before. The market increasingly demands the shortest possible delivery times and correspondingly greater flexibility of production. Minimal shutdown times as well as a fast start-up curve during start-up or restarting of the plant have become an absolute necessity today. A new plant concept is illustrated by the extension project of an existing Steckel mill with three finishing stands in tandem arrangement to increase its annual production. Furthermore, the quality of the products will be clearly enhanced thanks to the modified process and the selected technology. In order to implement all this with the highest possible commercial benefit, a revolutionary revamping concept, which reduces the mill shutdown period to a minimum, is introduced to the market. The so-called “add on products” have been developed to generate the highest possible benefit in existing facilities with limited expense and effort. Highlights include the differential tension looper and the tensiometer looper, the compact cooling system, edge masking as well as the on-line polisher.

This paper describes a method for producing model composites by the powder metallurgy route in order to control the spatial distribution of the reinforcement in a metallic matrix. The materials are fabricated by successive steps including mixing and extrusion. They are then characterized in 3D by X-ray tomography.

The application of finite element techniques to modelling the longproducts rolling process, the use of a customized interface to enablethe rapid set-up of sequential simulations, and the benefits thathave been obtained are described. The paper also discusses theenhancements to incorporate a design of experiments/design optimisationmodule and to enable material tracking.

A project was started in 2002 to improve the hot metal desulphurisationby ladle treatment, whose underlying mechanism was analyzedby a process model based on fundamentals. This allowed a10% reduction of reagent consumption. To reduce the treatmentcosts, calcium carbide was replaced by lime. Further results indicatethe need to improve the absorption of reaction products into theslag. Lime post injection resulted in lower final sulfur content andimproved slag removal.

Blast furnace No. 1 of Companhia Siderúrgica de Tubarão has been in continuous operation for 20 years, accomplishing a high operational performance with high productivity and low fuel consumption. With a view to reach the major objective of 18,500 t/m3/IV of productivity, several works have been carried out in order to extend the furnace campaign until 2008. This paper presents the results of these activities along with a proposal for a new concept of hearth wear.

It is economically important for manufacturers of high-temperature machines to be able to measure creep damage so they can predict residual service life more accurately. This paper describes and refines an image analysis method for evaluating creep damage in laboratory test pieces. It is a preliminary study of how to extract relevant information for damage measurement by cavities counting. Grain boundary extraction, which is directional information, is the major question to be overcome before measurement can be automated. The search for a crest-line extraction filter by the Canny method has led to the development of a directional wavelet transform filter. The results of this innovative filtering method are applied here.

With extremely high cooling rates, a combined laminar jet andspray nozzle design cooling facility is the most advanced tool forthe evolution of mechanical properties of high-strength steels. Themain metallurgical aspects of Accelerated Cooling (ACC) andDirect Quenching (DQ) are presented. Typical plate applicationsare brought up. Design, engineering and operational aspects ofmodern cooling facilities are explained. Of particular importancefor a homogenous cooling process is a powerful process controlfeaturing advanced process models.

The selective oxidation of three CMnSi steels with differentC levels was studied by XPS. The formation of a graduallycovering SiO2 film is observed until a transition temperatureabove which the oxide film disappears, resulting in a renewedappearance of metallic iron at the surface. This change inoxidation behavior is thought to be due to the SiO2 reductionby solute C which is thermodynamically favorable at hightemperature. At the same time the precipitation of a BN filmon the metallic surface was observed which prevented anyfurther oxidation.

This article tells in the form of a tribute to chairman René Damien, the founder of Usinor, the story of the French wide strip mills. The situation of the French steel industry in the 1950s is first recalled. The important decisions made to modernize this industry are then presented and the major milestones of the construction and operation of the hot strip mills of Denain, Serémange, Dunkirk and Fos are indicated.

The context of strong local sensitivity to dust emissions from an integrated steel plant like Sollac Dunkerque justifies the monitoring of the emissions of abnormally coloured smokes from this plant. In a first step, the watch was done "visually" by screening and counting the puff emissions through a set of seven cameras and magnetoscopes. The development of a new device making automatic picture analysis allowed to render the inspection automatic. The new system detects and counts the incidents and sends an alarm to the process operator. This way for automatic detection can be extended, after some tests, to other uses in the environmental field.

CST has among its priorities the sustainable development and basedon it the sinter plant unit has a commitment to reduce the atmosphericemissions, by developing actions that assure the continuousimprovement on process and the development of equipment linkedwith environmental control, and also with raw materials consumed inthe process. This paper aims at showing all evolutions on theenvironmental control at the sinter plant, with reference to dust andSO2 emissions, and also the visibility of the plume stack.

CRM developed a new cost effective procedure to have a moreaccurate assessment of roll performance related to oxide formation,friction level and wear for hot rolling. The procedure consists ofinserting different work roll materials in pilot work rolls to performspecific continuous pilot hot rolling campaigns with a detailed analysis.This gives a direct comparison between the different materialstested in a real rolling environment. Furthermore it reduces the technicalrisk related to the introduction of new work roll grades andspeeds up the roll development.

The hot ductility of Ti-bearing steel was studied by theoretical calculation and athermal simulation experiment. Meanwhile, microsegregation and precipitates were analyzed.The results showed that the S, P and O elements were enriched at the grain boundaries,while the hot ductility was deteriorated by inclusions of (Fe, Mn, Si, Al)(S,O) in theinterdendritic region. At a temperature of 1300 °C, large TiN particles have little effecton the hot ductility. In the temperature range from 1000 °C to 900 °C, the Reduction ofArea (R.A) declined rapidly from 81.77%to 31.77%, with the size of particles decreasing from 5 to 20 nm and quantity increasingfrom 1.2 inds/μm2 to 354 inds/μm2,respectively. In the temperature range from 900 °C to 850 °C,R.A decreased from 31.77% to 30.12%with the ferric films gradually thickening. The critical stress, 63.58 MPa, was equal totensile strength at 912 °C. Intergranular fracture occurred easily with higher criticalstress below 912 °C.