A methodology is proposed for taking recycling, an essential activityof the developed economies, into account within LCA tools. Thereasoning for choosing the methodology is exposed step by step.The final proposal is centered on the multiple-recycling model, whichbest describes the practical way that materials are actually recycledin the economy.
From a practical standpoint, the results obtained are attributed tosteel on the basis of a specific value (e.g. t of CO2 per t of steel),which amounts to averaging the impact over the various steps of therecycling process on a weighted average basis, depending on theamount of material recycled at each step.

Shipping containers have many names: cargo containers, sea cans, metal boxes, freightcontainers. Originally they were constructed, as the name reveals, “tocontain” and store items and mainly to transport goods. Freight containers are built tostrict international quality standards, to survive harsh treatment and a violent life inthe marine environment 1. The main technical detailsregarding containers were specified in an ISO (International Organization forStandardization) standard in January 1968 2. Thehistory of the shipping container starts like any other invention with a simple thought.It takes Malcom McLean, father of the shipping container, over 20 years to realize hisrevolutionary idea for the shipping industry and create a closed transport chain ofuniversal freight container for ships, trucks and trains 3. It wouldn’t be an exaggeration to say that shipping containers have laid thefoundation for globalization and changed the world. Over 95% of the worldwide tradeaffairs are winded up in containers. Today, international freight transportation is nolonger conceivable without containerization. There are approx. 28 million containerscirculating the globe. In the last couple of years up to 3 billion TEU (Twenty-footEquivalent Unit) shipping containers were produced annually, mainly in Asia 4. Most of the freight containers are made out ofCOR-TEN-Steel, which ensures strong carrying and loading capacity and supportswithstanding deformations or corrosion. Once they have served their purpose, shippingcontainers are being recycled as scrap. Another possibility is to be used in thearchitecture as spatial modules. A container’s life is ca.12 years and every year up to1.5 billion TEU are considered disused. The continued availability of shipping containersas a building block is thus assured. Therefore, the construction business with containershas a great potential regarding sustainability. In the last 15 years shipping containerconstruction has become popular for not only living spaces and homes, but for offices,studios, schools – the variety of uses is huge. Containers offer suitable solutions for awide range of uses. The increasing interest in these “icons of globalization” can beexplained with the fact, that they are relatively inexpensive, structurally sound and inabundant supply 6. Using old freight containerscould be seen as an environmental protection strategy and also as a redesign of technicalartefacts. Building with shipping containers is a new more affordable method ofconstruction and design. Due to metamorphose in functionality and meaning of containers –from a cargo box into a habitable space – we realize how big the technical range ofdiversity is. Technique reaches and changes the “Social” through design. The impreciseterm design, which has become a vogue term nowadays, is the interfacebetween technique, body, mind and communication 5.Designed objects are always also symbolic objects for different milieus; design has aneffect on awareness raising, thus on environmental awareness. An ongoing project at RWTHAachen University gives attention exactly to those disused shipping containers, theireventuality and boundary as environmental protection strategies in the living area, aswell as to the well-known cleavage between environmental awareness and environmentalbehaviour. The project focuses on the living situation in Germany and its potential forsuch new and innovative living concepts.

Gas-stirred treatment makes the ladle vibrate. Monitoring of thevibration has been studied in details: it is an industrial non-intrusivetechnique to control the process efficiency. Optimum gas stirringconditions can be defined, in terms of global kinetics of inclusionremoval at low vibration level.

The meniscograph and the sessile drop wetting methods, associatedwith in situ surface analyses, were used to quantify the influenceof the annealing atmosphere on zinc wetting during the hot dipgalvanising of high strength steels. If a clear wetting improvement isobtained for higher oxygen partial pressures, associated with a sufficienthydrogen amount, in the soaking area, a dry atmosphereabove the zinc bath has however to be preferred.

VAI has developed the MEROS® process (Maximized EmissionReduction Of Sintering) in which dust and harmful metallic and organiccomponents present in sinter offgas are removed in a series oftreatment steps to levels previously unattained with conventionalgas-treatment techniques. In a number of test campaigns, the technicaland economical advantages of this innovative sinter offgascleaningprocess were verified. voestalpine Stahl subsequentlyplaced an order with VAI for the installation of an industrial MEROSfacility to be started-up in August 2007.

In the model presented, phase transformations in steels are described using thermodynamic and kinetic laws at the scale of an austenite grain. A single geometric treatment leads to the final transformed fraction. The effect of composition, temperature path and austenite grain size is taken into account. The predictions of the model are compared with experimental results concerning different steel grades. The results obtained for ferrite, bainite and final ferrite grain size are encouraging.

Since contradictory data can be found in the literature, it is often difficult to assess the susceptibility of crevice corrosion of stainless steels in service conditions for a given marine application. The initiation and propagation of crevice corrosion in natural seawater were evaluated for five different duplex stainless steel grades together with some austenitic grades. A CREVCORR-type assembly was used to simulate crevice configurations involving the use of plastic crevice formers. The standard pressure applied on the crevice assembly was 3 N/mm2. Pressure of about 20 N/mm2 was also applied on some selected specimens in order to assess the effect of crevice geometry on crevice corrosion. The effect of environmental parameters (i.e. temperature, flowing conditions, residual chlorine, and dissolved oxygen content) and of surface roughness on the crevice corrosion initiation and propagation were investigated, allowing the assessment of limits of applications for some tested stainless steel grades. The less alloyed duplex stainless steels were evaluated in stagnant seawater at 5 °C and 20 °C. The duplex stainless steel UNS S32205, with PREN = 37, was also evaluated under the same conditions of exposure. The high alloyed stainless steels with PREN above 40 were evaluated in the expected most severe conditions of exposure, namely in 0.5 ppm-chlorinated seawater at 20 °C, in seawater at 30 °C (not chlorinated and with 0.5 ppm of residual chlorine) and in seawater at 50 °C (not chlorinated and with 0.5 ppm of residual chlorine). As expected the less alloyed duplex stainless steels showed limited crevice corrosion resistance in the tested media while UNS S32205 showed better resistance in the less severe tested condition of exposure. In demanding media it was shown that the limits of application of highly alloyed stainless steels are highly dependent on the crevice geometry (i.e. specimen roughness and applied pressure at gasket location).

The influence of TiO2 addition to LF refining slag on Ti-stabilized stainlesssteel was evaluated using a vacuum induction furnace at 1873 K. The effect ofCaO-SiO2-MgO-Al2O3 basic slags with different TiO2 contents on the titanium loss,aluminum loss and total oxygen content in the steel was studied. It was observed that theoxidation rate of Ti first decreases and then increases with the increase in the contentof TiO2 in slag andreaches the minimum when 8%TiO2 is added to the slag. However, the change in theoxidation rate of Al shows the opposite tendency. The total oxygen in the molten steelremains unchanged with time when 8%TiO2 is added to the slag, and the total oxygen of theothers increases monotonically with time. The activities of TiO2 and Al2O3 from the calculation of the ionand molecule coexistence theory (IMCT) in the initial slag present the same changetendency, and both first increase and then decrease with the gradual increase inTiO2 in the slagand reach the maximum when 8%TiO2 is added to the slag. The results of a kinetic analysisshowed that the rate-determining step of the oxidation of Ti in the steel is the masstransfer on the slag side, and the rate-determining step of the oxidation of Al in thesteel is the mass transfer on the metal side.

The hot-dip coating process faces a particular challenge with the production of high-strength steels. The backdrop to this challenge in the case of the high-strength steels is the enrichment of alloying elements necessary to control the microstructure at the steel's surface. These elements diffuse to the strip surface during the annealing treatment in the furnace and affect the wetting action of the molten zinc. The hot-dip galvanizing of high-strength steels has been tested in numerous laboratory and field trials. New methods for improving zinc coatability have been developed around the world. A focal point of the work at ThyssenKrupp Stahl AG has for this reason lain in the development of a new generation of multiphase steels that achieve an optimum surface quality also in conventional hot-dip coating lines.

La puissance débitée par les systèmes solaires ne cesse d’augmenter, soit par l’amélioration du rendement de conversion, soit par la multiplication des techniques de fabrication des photopiles solaires. Devant l’offre de fortes sources d’énergies conventionnelles à des prix relativement bas, l’utilisation du silicium polycristallin aboutit aux cellules polycristallines à faible coût de production. Cependant, les paramètres photovoltaïques de ce type de cellules sont affectés par l’existence des joints de grains et la ségrégation des impuretés à leurs niveaux. Ceci nous a ammené à nous intéresser dans le cadre de ce travail à l’influence des traitements thermiques sur le comportement électrique des couches de silicium polycristallin destinées à des applications photovoltaïques. Les résultats obtenus ont montré que les couches dopées arsenic sont plus résistives que celles dopées bore, et que les traitements thermiques réduisent le nombre de porteurs piégés et la quantité d’atomes de dopant aux joints de grains. D’autre part, cette étude nous a permis de constater que l’élévation de la température des traitements thermiques favorise l’augmentation de la conductivité électrique. De plus, la conductivité électrique dans des couches dopées bore est plus élevée que celle dans des couches dopées arsenic.

The main operating results of the European blast furnaces in 1998 are presented. The parameters influencing the productivity of blast furnaces are recalled. In Europe, actions have been taken to optimize blast furnaces operation: composition and quality of the burden, burden distribution, tapping practice, etc. Further improvements of the operating performances are expected.

The development of high tensile strength steels with higher levels of alloying elements needs the implementation of operating means in the continuous casting machine to master slabs internal soundness and surface quality. In order to define optimal process parameters according to the characteristics of the different continuous casting machines and to optimize the revamping of older equipment, thermomechanical modelling of the steel slab behaviour during casting has been carried out. This paper presents the results of simulations performed to check the potential of this modelling.

This paper describes how an optimization of the rolling conditions (roll lubrication, strip chilling) and the use of new roll qualities on the 2050 mm hot strip mill at Iscor Vanderbijlpark, allowed to realize the full potential of HSS rolls. Based on development work and laboratory studies on oxidation behaviour, these improvements benefit both to Hi-Cr and HSS rolls. The full implementation of HSS in stands F1 to F4 during year 2000 will allow to increase the mill availability by eliminating the intermediate roll change and reduce the work load in the roll shop.

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 different models of sintering are reviewed, with a special attention to the developments in the last fifteen years. The models are classified between microscopic models, which describe the evolution of the material with a cell containing one or a few particles, models at the scale of the particle packing, and macroscopic models, which describe the evolution at a scale which is large compared to the particle size. Perspectives for the future are briefly discussed.

A comprehensive three-dimensional (3D) stochastic model for simulating the evolution ofdendritic crystals during the solidification of binary alloys was developed. Themulti-scale model takes into account all the length scales (e.g., macro, micro- andmeso-scales) required to accurately predict the evolution of dendritic morphologies duringsolidification of alloys. The model includes time-dependent computations for temperaturedistribution, solute redistribution in the liquid and solid phases, curvature, and growthanisotropy. Stochastic models previously developed for simulating dendritic grains in 2Dwere modified to control the nucleation and growth of dendrites in 3D. 3D mesoscopiccomputations at the dendrite tip length scale were performed to simulate the evolution ofcolumnar and equiaxed dendritic morphologies including segregation patterns and comparedthen with predictions based on 2D mesoscopic computations.

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.

First, it is demonstrated that the shape change accompanying bainite formation is accommodated by plastic deformation in austenite. Secondly, taking into account the corresponding plastic work, which increases due to carbon enrichment and transformation shear strain, as an entropy production mechanism, a new criterion, depending especially on initial chemical composition and grain size of austenite, is proposed for the stop of isothermal bainite before the expected equilibrium fraction expected from the phase diagram.

Emission limits of the sinter waste gas have been continually andstrictly tightened in the EU for the last years. To cope with these environmentalchallenges, a survey about the sinter plant flue gas cleaningtechnologies was carried out within the VDEh sub-committee“Burden preparation”. This paper summarizes the main results of thissurvey and describes briefly principles of different processes andtechnologies including some of the latest development in the field ofsinter waste gas cleaning.

Oil layer and surface roughness of steel strip are measured on-linewith equipment that has been adapted to withstand the severe environmentof a cold rolling mill. The system ensures the effective lubricationof the strip and it displays roughness data all along the coil.This makes it possible to optimize the rolling process on-line and itaffords comprehensive information on the strip properties.