Good stability of the steel strip is essential in galvanizinglines, especially in the rapid cooling section before the zincbath, where the strip is cooled and excited by high-speedgas jets.
The process parameters and the design have beeninvestigated in order to characterize the strip vibrationsphenomena and to define optimized solutions for improvingthe cooling performances of present and future galvanizinglines while reducing the strip fluttering in the rapid coolingzone as well as in the cooling tower.

Steel rolling technology has achieved such fantastic progress in the 20th century that it might be considered to have come to maturity.Actually, it remains nowadays the object of intense development thataffords further impressive improvements. The progress of rollingtechnology is fostered by a drastic global growth of the number ofrolling equipments on the order of 40% over the last 15 years. Itbenefits from a dedicated R&D effort based upon a large scope ofscientific knowledge. The 9th Steel Rolling Conference illustrates thispotent innovative approach and it offers a unique opportunity forfruitful exchanges between steel producers, equipment suppliersand steel users.

Fe-Al alloys containing 25 and 31.5 at. % Al have been studied by internal friction, X-ray diffraction and dilatometric analyses. These techniques show for the first time that two internal friction peaks appear during the change in long range order type which occurs during the precipitation at 300°C of the metastable phase B2(FeAl). These peaks correspond to the formation of two phases: the equilibrium phase Fe3Al and a new intermediate tetragonal phase θ.

An approach is proposed for the evaluation of surface fatiguedamage of hot forming tools that undergo severe thermomechanical loading. Fatigue crack propagation in a hot worktool steel X38CrMoV5-47HRC is investigated using singleedgecracked tension specimens with 3 different thicknesses(2.5, 1, 0.6 mm) and two R-values. The stress intensity factoris evaluated with ABAQUS®. Paris curves are established forthe crack propagation experiments.

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.

The fire resistance of structures is one of the main brakes concerning the development of steel in buildings. This handicap of steel is in order to disappear due to the results of recent researches that permit to dimension the steel structures by considering the natural fire and the active fire fighting measures. In the frame of an ECSC financed research, an interactive calculation software has been developed with the aim of enabling engineering offices to perform easily calculations under natural fire conditions. This paper describes this new tool that should contribute to the promotion of steel by making the dimensioning under fire conditions easier and more competitive.

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.

A new 400,000 ton/year 2-stand temper and double reduction mill has started production in April 1999 at Dongbu Steel Asan Bay Works in Korea. This facility produces skin-passed and double reduced tin mill black plates. The line incorporates state of the art technologies including AC motor driven 4-high CVC mills and computer integrated automation systems. The line has the capability of producing products 600 mm to 1,250 mm wide and in gauges from 0.15 mm to 1.0 mm for skin-passed products and from 0.15 mm to 0.36 mm for double-reduced products. An outline and the features of the line as well as the quality characteristics of the products are presented.

Cementite decomposition leading to the formation of the whiteetching layer (WEL) on the surface of rail tracks was investigated byelectron energy loss spectroscopy (EELS) in the TEM and by threedimensionalatom probe (3D-AP). It is shown that the carbonconcentration inside cementite laths undergoing severe plasticdeformation in the transition zone between the pearlitic substrateand the WEL remains stoechiometric. However there exists a boundarylayer at the ferrite/cementite interface where the carbon compositiondecreases, indicating that decomposition is an interfacialphenomenon. Carbon atoms diffuse into the ferrite and segregatealong structural defects leading to a heterogeneous supersaturatedcomposition in the white etching layer.

Dans le cadre de l’étude de la fatigue thermique de tuyauteries du parc de centralesnucléaires, des essais de fatigue multiaxiale à grand nombre de cycles sont effectués pourtenter de quantifier l’effet de la multiaxialité et de contrainte moyenne sur la durée devie du matériau et alimenter un modèle d’endommagement à deux échelles. Des outils demesures de champs cinématiques ainsi que d’observations micrographiques sont mis en placeafin de tirer le maximum d’information de chaque essai : comportement cyclique,déformation plastique progressive, scénario d’apparition des fissures. Des résultatsd’essais proportionnels et non-proportionnels sont présentés.

EU regulations to be proclaimed will insist on product life cycle, Health-Safety-Environment issues and they will further enforce new ecotaxes. Anticipating these demands would afford Steel a competitive advantage and would further improve its image. The objectives of coated steel products, both in terms of process and properties are presented. The new developments of high performance steel surfaces are highlighted.

Textures and local orientations have been determined in copper alloys after cold rolling and annealing. The measurements show that for a strain below a given threshold a mixed “deformation-recrystallization” texture is obtained after a static primary recrystallization : the {100}<001> cube orientation becomes stronger as annealing procedes, but is not dominating in the final microstructure. Global texture determinations by X-ray diffraction coupled with local orientation measurements by EBSD (Electron Back-Scattered Diffraction) show that in materials cold rolled by 70 and 80%, the orientation changes at the very beginning of the recrystallization process (i.e. at nucleation) are crucial for the formation of the recrystallization texture.

CRM developed a probe determining the raw material trajectories in bell-less top charging, by measuring the force generated by the material stream on a beam, in function of its position in the furnace. A prototype probe was tested on an industrial blast furnace during its first charging after a relining. These trials allowed the determination of both coke and sinter trajectories for the various chute angles. These results were validated by measurements carried out simultaneously by Irsid with painted bars.

This communication presents experimental observations of plastic deformation in submicronic metallic multilayers. As the length scale decreases down to the nanometer range, we evidence a major change in deformation mechanisms, plasticity becoming less localized as in traditional slip bands of dislocations. AFM and nanoindentation techniques are used in conjonction with more standard techniques to characterize plastic deformation.

Tests were performed on austenitic stainless steels. In order to investigate thermal fatigue resistance of quasi-structural specimens, test facilities enforcing temperature variations similar to those found under the operative conditions have been developed. Multiple cracking networks similar to those detected during in-service inspections have been reproduced. Experiments and simulations deal with crack initiation and crack growth. In the case of multiple cracking simulation, a Skelton's modelling has been used. A shielding effect between cracks is evidenced. It leads to a dramatic reduction of crack growth rate. Such effect is also crucial for the crack network stability under additional loading.

The damage behaviour of materials depends strongly on the residual stresses generated inside the coatings realized under high energy beams. The purpose of the present work is to demonstrate the effect of intrinsic and geometrical parameters of the coated system on the stress level at the coating surface. The results of the elaborated phenomenological model show that the residual stress level depends, in particular, on the substrate and coating modulus ratio. It is then possible, based on the judicious choice of this ratio, to optimize the stress level.

CRM is studying the possibility to comply with stringent PMregulations by improving the collection efficiency of existingdedusting systems, in order to avoid investments in expensiveadditional abatement means. The idea is to agglomeratefine dust particles together or onto coarser ones by applyingultrasound to the dust laden waste gas flow, upstream of thededusting unit.

The trapping of carbon by titanium in ferritic stainless steels with low interstitial contents depends on the presence of other non metallic elements such as phosphorus. The decrease of phosphorus content in the steels promotes the segregation of carbon at the grain boundaries and prevents the formation of the titanium carbonitrides. In fact, the formation of these precipitates depends on the quantity of remaining carbon in the matrix after the segregation of this element at the grain boundaries. Thus, this quantity could be sufficient to allow the formation of Ti(C, N) compounds by reduction of their solubility as the tempering temperature is decreased.

In spite of an extensive bibliography available, the solubility limit of carbon in ferrite is still uncertain (between 50 and 100 ppm at 600°C for example), and this is not sufficient for the improvement of steel processing. Therefore we have tried to establish as accurately as possible the solubility of carbon between 500 and 750°C in a low carbon aluminium killed steel using a thermoelectric power protocol, which enables to calculate the amount of free interstitials in a ferritic matrix from the amount of interstitials that segregate on dislocations after strain. The solubility limit has been determined at ± 2 ppm between 550 and 730°C, and described by the relation: C(%wt) = 6.63 exp(-11.8 kcal/mol/RT). At a time when metallurgical phenomena are more and more simulated, we believe that a similar procedure should be used for other experimental studies providing basic data for modelling.

In this paper, the effect of an annealing treatment on the microstructure, mechanicalproperties and electrical conductivity of a deformed Cu-12.8 wt%Fe composite prepared bythe “casting/cold working” process is investigated. The Fe filaments exhibit the shapecharacteristic in the as-drawn composite as the annealing temperature is lower than 500°C. When the annealing temperature is above 500 °C, the Fe filaments undergo theinstability process in terms of boundary splitting, coarsening and breakup gradually. Thetensile strength gradually decreases with increasing annealing temperature due to thecoarsening of filament spacing. The work hardening for the composite annealed above 600 °Cis slower than that annealed at a lower temperature. The electrical conductivity reaches amaximum of 60%IACS at a temperature of 450 °C for one hour of annealing, and it furtherincreases with increasing annealing time at 450 °C to reach a plateau of 68% IACS. Thecurve between the tensile strength and electrical conductivity under different annealingprocesses indicates that the optimum annealing temperature for the Cu-Fe composite is 450°C.