A goniospectrophotometer is used to analyze the back-scattered light, in the visible range, by a 0.3 cm2 surface. The measurement is non-destructive, without contact and can be implemented in situ. For a metallic surface, the reflected intensity is measured as a function of the back-scattered angle. The probability density of the normal to the surface is then deduced. The ratio roughness r.m.s. / correlation length is calculated. The method is applied to characterize the different techniques for gold backgrounds in primitive European paintings. For a non-metallic surface, the reflected intensity is measured as a function of the wavelength. The spectrum is compared with a data bank of mineral pigment spectra. The comparison allows to identify pigments and, moreover, to deduce the surface state of the painting layer. Examples of Egyptian and modern paintings will be presented.

For over a decade, Continuous Casting has been a maturetechnology that has prevailed in the steel industry. ConventionalCC is still undergoing small but deep and subtle transformations.Thin Slab Casting is developing at a rate commensurate with theneed of new capacity. Strip Casting has been limited to industrialpilot lines, although commercial implementations have beenannounced. In the perspective of the changes that the steel industry will haveto undergo in the 21st century (control of Greenhouse Gasemissions in particular), continuous casting will be one of theinvariants to provide a degree of stability. Indeed, solidification willmost probably continue to be performed on continuous casters.

The blow-in of CSN blast furnace n°3 in 2006 is reported with a focuson a large solidified salamander that had to be tapped. Analyticaland finite element models have been created to predict the expansionphenomena. The predicted values are compared with the hearth shellstress and strain measurements executed during the blow-in.


The recent decrease in Blast Furnace production as well as changes in raw materials andprocess conditions has produced an increase in the silicon and phosphorus contents in hotmetal. This situation increases the probability of slopping and fume emissions duringconverter blowing because of the large volume of highly viscous slag. To carry out thesilicon oxidation and dephosphorization steps, a double slag practice has to be used. Thefirst slag is rich in silicon and phosphorus and has a low basicity. The first slag isremoved. Then the second slag is formed; this low-viscosity slag is subject to the strongagitation created by a high decarburization rate. The second slag is characterized byhigher CaO and phosphorus contents. These conditions yield a better dephosphorization atthe end of the blow. In order to implement the double slag practice, the converter controlsystem was modified. The changes included the design of the lance blowing pattern, theflux additions, the static control, and the logic of the gas collection and cleaningsystem. For a silicon content larger than 0.60% in the hot metal, the results show asignificant reduction in the fume emissions and in slopping, a lower flux consumption, andopen up the possibility of working with iron ore with higher phosphorus content.

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 a HIP operation, conventional control of the process variables (T, P) is the current mode used. The process variables follow a prespecified trajectory (schedule) assumed to lead to the final quality of product. A second mode is advanced control, where on-line measurements of a product state variable enable to monitor the evolution of the product variables and if necessary to compute corrections to the schedule in order to obtain the desired quality of the final product. HIP advanced process control requires continuous monitoring of the sample density during all stages of the process and the on-line identification a process model. To this end, a dilatometer has been built for in situ monitoring densification during a HIP operation, the Ashby process model has been validated and on-line identification has been demonstrated. It is shown that advanced process control of a HIP operation can be performed in two steps : on-line identification of the process model and subsequent process path replanning. The first step can only be performed during the process variables plateau of the preset temperature-pressure cycle, and process path replanning consists of a new temperature-pressure plateau.

Les boulets de broyage ou de concassage sont des éléments de broyeurs utilisés dans lescimenteries; ils exigent une résistance à l’usure élevée sous l’action de produitsabrasifs lors de la transformation de la roche en fines particules de taille inférieure aumillimètre. Les traitements thermiques constituent une étape essentielle pourl’élaboration du boulet. Ils permettent d’obtenir des duretés et une résistance à l’usureconvenables. Les analyses structurales et microstructurales par diffraction X etmicroscopie électronique à balayage permettent de comprendre leurs corrélations. Dans cetobjectif, nous avons étudié l’influence de quelques facteurs déterminants dans cestraitements. Les facteurs considérés dans le présent travail sont : la températured’austénitisation (950 °C et1050 °C), la sévérité dumilieu de trempe (refroidissement à l’air ventilé et à l’huile) et le diamètre des boulets(boulets de diamètre 50 et 70 mm). Les résultats obtenus ont révélé la présence decarbures de type Cr7C3 répartis dans une matrice martensitique ou ferritique etque le taux de l’austénite présent dans les boulets trempés à l’air ventilé est inférieurà celui des boulets trempés à l’huile. La température d’austénitisation et la taille desboulets influent sur la trempabilité. En effet, l’écart de dureté entre la surface et lecœur des boulets de diamètre 50 et 70 mm chauffés à 1050 °C, refroidis à l’air ventilé et à l’huile,est plus important que celui des boulets correspondants chauffés à 950 °C. Une augmentation de la taille desboulets conduit à la diminution de la trempabilité notamment les boulets de diamètre 70 mmchauffés à 1050 °C.

Les métaux liquides sont envisagés pour des applications très variées comme les cibles de spallation, les réacteurs nucléaires de génération 4 ou les futurs réacteurs de fusion. Des recherches sont actuellement menées sur l’interaction des aciers, seuls matériaux de structure compatibles, avec les métaux liquides comme l’eutectique plomb-bismuth ou le sodium. Dans ce problème de vieillissement des matériaux, on s’intéresse tout particulièrement aux problèmes de corrosion, de mouillage et de rupture induite par l’interaction avec le métal liquide. Cette revue reprend quelques éléments de la compréhension actuelle des ces phénomènes.

The instrumentation of an industrial vacuum arc refining furnace (VAR process) has allowed for the first time to visualize the electric arc during the remelting of a zirconium alloy. This device, recording fast video observations in synchronization with the high frequency voltage changes of the arc, has been applied to the study of the behaviour of the arc and of the transfer mechanisms of the liquid metal to the ingot. Results are given for current densities of about 10 to 20 A/cm2 and arc lengths smaller than 6 cm.

X-ray absorption spectroscopy has been applied to probe the local structure of FeSc nanostructured amorphous solids around Sc atoms. At the Sc K-edge, the Fe90Sc10 nanoglass is characterized by a very short range order (EXAFS oscillations are only present up to k = 8 Å-1). A drastic difference in the phase and the amplitude of the nanoglass EXAFS signal compared to the amorphous ribbon indicating a different local structure around Sc atoms in both structures is observed. In addition, the changes in the local structure around Sc atoms are more significant than around Fe atoms.

The innovative technological solutions by VAI (VOEST-ALPINE Industrieanlagenbau, Austria), which are presented, allow to obtain substantially improved results for profile and flatness of hot rolled strip. These solutions concern, on the one hand, the design of rolling stands and rolls and, on the other hand, highly modern numerical models for the control of the important parameters.

A novel rheo-rolling process for producing A356 alloy sheet was developed. The influenceof parameters on the microstructure of A356 alloy sheets was investigated. The eutecticfraction and primary α globule size increase with the increment in theroll speed. The globule size and eutectic fraction of A356 alloy sheet increase with theincrement in the casting temperature. The primary α globule sizedecreases and the solid fraction increases with the increment in vibration frequency from30 Hz to 80 Hz. With a roll speed of 0.069 m.s-1, a casting temperature of 660°C, and a vibration frequency of 80 Hz, A356 alloy sheet with a cross-sectionsize of 4 × 160 mm was prepared. The microstructure is mainly composed of fine sphericalor rosette α globules, and the average α globule size is20.5 μm. The ultimate tensile strength of the A356 alloy sheet was 260MPa, and the elongation to failure was 7.9%, which were 2.5 and 3.7 times greater thanthose of the as-cast material.

In this paper an extension of the sintering method at atmospheric pressure, already used for tool steels, is proposed for prealloyed duplex stainless steel powders. A wide temperature range is tested and the effectiveness of boron as activator of the process is investigated. In all the samples no evidence of liquid phase is observed ; the sintering process allows full density in case of no boron addition and it occurs by solid phase diffusion, enhanced by the presence of two phases, austenite and ferrite : this makes needless to add boron as activator. We obtain density and hardness values comparable with the “as-cast” ones, isotropic phases structure and γ/δ ratio of about 50/50 for the best sintering temperature (1150 °C).

A new automated system installed in the ArcelorMittal Asturiassteel plant in Avilés, based on novel image treatment, aimsat performing an on-line inspection, with feed-back to theprocess, verifying the effectiveness of scarfing. It detectsremaining defects as well as new ones introduced by thisoperation, thus allowing a quick and reliable assessment offinal surface quality.

Principle and technological design of electroslag continuouscasting (ESCC), including bifilar mode, T-shaped mould andmetal level detecting system are detailed. Remelting is carriedout for a Cr18Ni9Ti stainless steel with ESCC. The surfacefinish, chemical composition, macro and microstructures, andinclusions of remelted billets are characterized. ESCC reducescost and increases productivity in comparison to the traditionalESR, while achieves comparably excellent products.

In continuous hot dip galvanizing, in particular with galvannealing baths, competitive reactions occur between iron, zinc and aluminium that may be affected by other elements such as chromium. Based on thermodynamics modelling and experimental descriptions, the zinc rich corner of the quaternary Fe-Zn-Al-Cr system is investigated at 460°C. The results obtained contribute to a better knowledge of the reactivity of steels in industrial galvanizing or galvannealing baths.

For advanced high strength steels for automotive application, the time between materials development and regular use in cars, trucks and similar vehicles is rather short. In contradiction to this, hot rolled plates made of high strength low alloy steels which have been developed many years ago still do not find application fields in structural steelwork although they offer impressive mechanical properties. In this paper we argue that inadequate design rules in civil and mechanical engineering prevent such modern high strength steels from displaying their lightweight potential. A technological approach to the problem presented in this paper is to apply damage mechanics models together with probabilistic safety concepts for derivation of new improved safety factors. However, a major obstacle in this process is that these new safety factors will have to be included in the design standards. The development of such standards contains both institutional and epistemic obstacles to including alternative safety models. Taking standardization in Europe as an example, the standardization committee is characterized by both national interest representation and attempts to stimulate European integration and competitiveness. At the epistemic level, different understandings of what counts as evidence for material safety may challenge and postpone adoption of new calculative models. Institutionalization and epistemology thus contribute to a framework for standardization that needs to be questioned in order for new approaches to be accepted. Such questioning cannot be done on the basis of developing new calculation models alone, but needs a clear social component of building coalitions around the inclusion of new considerations, for example those related to sustainability.

This paper describes a simple and efficient method to identify Young's modulus of thermally sprayed coatings. The mechanical method is based on the cantilever beam test, without the use of a strain gauge, combined with a finite element numerical modelling and optimization technique. The influence of coating roughness was taken into account in this work. Several types of coatings were tested and their Young's moduli were calculated. A sensibility analysis was also performed.

Bulk metallic glasses foams are under consideration as highly functional material, such as energy absorbers or ultra-lightweight parts, due to their porous structure combined with desirable strengths at relatively low densities. Also, the characteristics of high surface area of foams synthesized from metallic glasses make them viable candidates as emerging materials such as high-sensitivity sensors, catalysts or hydrogen storage media. In current study, bulk metallic glass foams were fabricated by extruding powder mixtures comprised of metallic glasses blended with various kinds of fugitive phases followed by dissolution of the fugitive phases in an aqueous chemical solution, for example HNO3, to yield the final porous structure. As a result of dissolution process, porous metallic glass having uniformly distributed micro-scale porosity was fabricated using a sequential synthesis technique beginning with composite particles comprised of composites of MG and a fugitive phase followed by consolidation of the composite powders via warm extrusion.

Steel slag is a steel-making industry by-product, currently used forseveral applications in substitution of non-renewable natural resources(e.g., crushed stone and sand). The major reason for conductingthis study at CST ArcelorMittal Brasil was to verify if any of the currentuses of LD and NP slag presented significant risks to the environmentand/or human health.