The evolution toward equilibrium of the supersaturated Pb-1.5%Cd-0.15%Ag-1.25%Sn alloy has been studied by various techniques, such as hardness, optical microscopy, scanning electron microscopy and electron microprobe. The explored temperatures are 20 and 80°C. The precipitation hardening mechanisms of this alloy are similar to those of silver-free alloys. The as-quenched structure transforms toward equilibrium in a two stage process. In the first stage, called ageing, two transformations take place at the same time: a continuous hardening precipitation and a discontinuous, incomplete, softening transformation. The second stage is characterized by a discontinuous lamellar reprecipitation. The microstructure of this alloy is characterized by the presence of Ag5Cd8 precipitates and of zones corresponding to the eutectic mixture. The main effect of silver is to increase hardness by about 2 HV.

This paper gives a brief overview of process control in slab reheating furnaces, zooming on the so-called “funnel-concept”, as this is implemented at Corus IJmuiden this year. The control automation in reheating furnaces at Corus started in 1970. In 1985-1990 an on-line slab temperature calculation and control system has been developed and implemented at pusher-and walking-beam furnaces. Ongoing development of this model resulted in a control strategy where the target-heating curve of each individual slab was extended by an upper and lower limit, of which the interval at the entrance gradually diminished to the end of a zone: the funnel model.

The prolonged holding at high temperature of certain cast cobalt base superalloys may lead to rarefaction and fragmentation of the tantalum carbides which harden these alloys. Room temperature hardness, thermal dilatation and high temperature tensile strength have been studied in relation with these processes. Only the thermal dilatation coefficient and the modulus of elasticity are really affected by the evolution of the tantalum carbides.

A zinc-pigmented corrosion protection primer is being used by the automotive industry. This state of the art “first generation” type coating is now applied on a chromate-free pre-treatment. It has been further developed and is now called the “second generation” corrosion protection primer. This new coating type has a higher thickness with double the amount of corrosion resistance and has a curing temperature suitable for BH-grade steels. The properties in corrosion, forming, welding and adhesive bonding together with the potentials for the automotive industry in using it will be presented from the viewpoint of a steel and automotive producer.

In November 2000, UGINE&ALZ Genk awarded VAI a contract to upgrade their steelmaking plant. The scope of work included the world's largest stainless steel slab caster designed for an annual output of 1.2 million tons. The existing casting machine had to be replaced within a comprehensive shut-down period of 21 days only to minimize the financial burden due to the production outage. Innovative project management solutions combined with excellent realization resulted in a successful start-up on October 1, 2002, after a shutdown period of only 20 days. Operational results with regard to productivity and quality are discussed.

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.

A micromechanical model based on a new self-consistent formulation has been applied to describe the elastic-viscoplastic behaviour of steels at high strain rates. A good agreement between experimental and calculated data is found concerning the behaviour of a ferritic single-phase IF steel in uniaxial tests in a large range of strain rates. Because of the introduction of relevant physical parameters in the modelling, a good description of the difference observed between the Dual-phase steel and the single-phase steel is obtained.

Brillouin light scattering has been used to investigate the elasticity properties of polycrystalline smooth fine-grained diamond films having various diamond qualities. They have been deposited on titanium alloy Ti-6Al-4V by a two-step microwave plasma-assisted chemical vapour deposition process at 600°C. Taking advantage from the detection of a number of different acoustic modes, a complete elasticity characterization of the films has been achieved.

The research on structural materials, notably in metallurgy, was the pioneering discipline of the materials science. Besides “traditional” materials as metallic alloys and polymers which are following up their progresses, the materials of wide uses and large diffusion, like concrete, rubber, textiles, wood, paper and cardboard are now benefiting of the advanced researches allowed by the progresses of the investigation and modelling methods able to provide information on their great complexity linked to the fact they generally are mixtures. High strength materials gain from active researches dealing with experimental studies as well as modelling of the production processes, multiscale approaches of the structures, properties, behaviour and optimized selection providing both scientific advancement and improved applications. “System-materials” are another field of stuctural materials, often in connexion with functionnal materials. Artificially built by putting together elements going from atoms to fibers or particles of different sizes: composites, smart materials, structural nanomaterials have opened the way to wide research perspectives and exiting applications. Interdisciplinar researches on optimized mechanical behaviour, chemical and topological analysis of the microstructure and processes modelling, multiphysics modelling of the behaviour of structures and properties are developed thanks to the advancement of the available instrumentation and calculation facilities. Studies on the implementation of these materials providing an improved control of the performances of the produced parts and objects need a renewed stimulation. Data bases concerning thermodynamic properties as well as kinetics ones, mechanical and thermophysical properties are necessary input data for these approaches and improvements. A continuous enrichment of these bases is of vital importance.


By depositing PVD coatings on already conventionally galvanized steel sheets novel zinc alloy coatings have been developed. One of the biggest advantages of PVD coatings lies in the broad choice of coating materials as there are no constraints due to chemical reactions between the substrate and the coating. This leads to a variety in the coating compositions. Accordingly, PVD processes enable customized solutions for various purposes. Magnesium on galvanized sheet steel has been identified as a very promising coating system. Corrosion performance is improved considerably while other properties like forming, joining and painting are comparable to or better than the untreated galvanized material.

CRM has developed a technique to measure the hydrostatic pressure in the blast furnace hearth. Three measuring campaigns have been performed at Arcelor Cockerill-Sambre BF B. Complementarily, a mathematical model computing the liquid levels in the hearth and the position of the bottom of the dead man has been developed. It takes into account the movement of the dead man. Its results are consistent with the pressure measurements. The combined use of the model and the measurements allow estimating the coke bed voidage in the hearth and concluding if the dead man is floating or not. For most casts, it beginsto float a few minutes after plugging. The estimated coke bed voidage is very well related to the quality of the coke used during the measuring campaigns.

“Consistent BOS Performance” was an ECSC funded project that began with the premise that internal converter shape influences process performance. Plant data were analyzed to quantify the effect of shape on performance and the process of slag splashing was studied in detail, as a means of shape control. It was found that the greatest influence on BOS performance is the availability of bottom agitation and this is affected by slag splashing practices.

The high temperature oxidation behaviour of cast superalloys strengthened by carbides has been studied as a function of their grain fineness and their dendritic orientation near the surface. These microstructural features have both a significant influence on the oxidation kinetics. The effect depends on the nature of the base metal of the superalloy, on the overall chemical composition or on the types of carbides.

The technology of slag processing by rotary cylinder at Baosteel has many advantages, such as short flow, higher efficiency, more safety, lower consumptions etc. Processed slag has stable properties and small but symmetrical granules, lower contents of free-CaO, and it can be used directly in many areas.

This paper presents some of the highly modern and innovative solutions used by VOEST-ALPINE Industrieanlagenbau (VAI) to comply with the high quality and productivity requirements set for the stainless steel slab continuous casting machine supplied to the Tornio plant of Outokumpu Oy and started up in September 2002.

A digital system has been implemented on the hot strip mill of CST to record and to collect on-line images of the strip and of the equipments at critical locations. All the data from fixed camera or from “scanning” cameras with extended scopes are displayed through Internet to the HSM operator and maintenance staff. The system is very effective and is a major asset for fault analysis as well as for the on-line strip to strip optimization of the rolling parameters by the operator. The system has allowed deeper investigations at the coil box, at the finishing mill and at the down coilers. Indeed the very intricate nature of fast events that occur at these locations make them difficult to be observed on-line by any operator.

The effect of blast furnace productivity on the erosion of the hearth wall and the campaign life was examined. First, the molten iron flow in the hearth was studied by a model experiment and an iron flow estimation model calculation. Next, the temperature distribution in the hearth wall was calculated by a heat transfer model, and the erosion of the wall and formation of the solidified layer were estimated. The study led to the erosion pattern during the blast furnace campaign life, which was verified by the actual furnace erosion pattern.

The method of residual stress determination based on X-ray diffraction has been used for the study of different types of stainless steels: single phase or multiphase microstructures, different inclusion contents. A thermomechanical model associated with a finite element code is proposed for the determination of the stress field in relationship with the actual microstructure and texture of the materials. The numerical calculations are validated by comparing the obtained results to those experimentally determined and by scanning electron microscope observations on the initiation zones of microcracks.

The accidental melting of radioactive sources is impossible to prevent completely because some radioactive sources are extremely difficult to detect. When a radioactive source is melted, the people involved have concern for their safety, and there can also be very large costs to the steel plant. The aim of this study, sponsored by the European Commission, has been to give guidance to steel makers on the radiation safety aspects of an incident, and on what measures should be taken to minimize the impact on the steel plant.

Mould level variations, which are a significant cause of slab downgrading and production troubles at the continuous casters, can result from bad performances and low reliability of control equipments. A revamping project was realized at Dunkirk, after studies and prototype trials which enabled us to select the different components: stopper mechanism and actuating cylinder, level sensor, control electronics. A specific start-up organization, allowing for daily analysis of signals and results and frequent contacts with the engineering team, has permitted to reach quickly the targeted performances.