The permeability of the blast furnace and in particular of its lower part, conditions its performances and its campaign duration. It is therefore essential to be able to characterize it. Several methods have already been used as radioactive tracing, coke core boring and Iiquids sampling, achieved by the tuyere probe installed on the BF 1 of Sollac Fos. Results of these measurements can be completed by gas analyses on the blast furnace radius and by gas tracing using helium, also achieved with the tuyere probe. This article presents the synthesis and shows the consistency of these various measurements.

Emergy evaluation (EME) is an environmental assessment method which isgaining international recognition and has increasingly been applied during the lastdecade. Emergy represents the memory of the geobiosphere exergy(environmental work) – measured in solar emjoules (seJ) – that has beenused in the past or accumulated over time to make a natural resource available. Therationale behind the concept of Emergy is the consideration that alldifferent forms of energy can be sorted under a hierarchy and measured with the commonmetric of the seJ, which is then the yardstick through which all energy inputs and outputscan be compared with each other. For this reason EME is suggested to be a suitable methodof environmental accounting for a wide set of natural resources, and can be used to defineguidelines for sustainable consumption of resources. Despite those interesting features,EME is still affected by several drawbacks in its calculation procedures and in itsgeneral methodological background, which prevent it from being accepted by a widercommunity. The main operational hurdle lays in the set of mathematical rules (known asEmergy algebra rules) governing EME, which do not follow logic ofconservation and make their automatic implementation very difficult. This work presents anopen source code specifically created for allowing a rigorous Emergycalculation (complying with all the Emergy algebra rules). Wemodeled the Emergy values circulating in multi-component systems with anoriented graph, formalized the problem in a matrix-based structure and developed a variantof the well-known track summing algorithm to obtain the totalEmergy flow associated with the investigated product. The calculationroutine (written in C++) implements the Depth First Search (DFS) strategy for graphsearches. The most important features of the calculation routine are: (1) its ability toread the input in matrix form without the need of drawing a graph; (2) its rigorousimplementation of the Emergy rules; (3) its low running time, which makesthe algorithm applicable to any system described at the level of detail nowadays madepossible by the use of the available life cycle inventory (LCI) databases. A version ofthe Emergy calculation routine based on the DFS algorithm has beencompleted and is being tested on case studies involving matrices of thousands of rows andcolumns, describing real product production systems.

The operation of an economy is supported by the stock of materials in the form of durables and infrastructure such as machinery, equipment, buildings, and structures. The amount of durables and infrastructure or “capital stock” in the economy is of great interest in the literature of economics, and is usually measured in monetary terms based on the data on capital expenditure. In spite of its wide use by economists, this measure of “capital stock” is of very limited use for sustainable management of material stock because of its neglect of physical properties such as the mass and material composition. This paper proposes a new method of measuring the stock of long-lived durables and infrastructure in terms of the mass of its materials. This method is based on the WIO-MFA method [S. Nakamura et al. J. Ind. Ecol. 11 (2007) 50-63] and the capital formation matrix that is one of the supplementary tables of the input-output table. The method is applied to the Japanese input-output data with 400 sectors, with 9 types of metals (iron, ferroalloy, copper, zinc, lead, tin, aluminum, silver, and gold) and 8 types of plastics (thermo-setting resins, PE (low), PE (high), PS, PP, PVC, high-performance resins, and other resins) occurring as materials. It was found that substantial variations exist among sectors while fixed capital formation in the year 2000 weighs 518 kg per million Japanese yen on average in metals and plastics.

The steps of the conventional production process of stainless steel cold rolled strip are recalled, as well as the evolutions that have preceeded the design of the LC2i line. The advantages and constraints of this integrated and continuous line are outlined. The main equipments coupled in the line are described and their characteristics presented. Automation, work force training, TPM, protection of the environment have been essential features in the project.

A numerical tool has been implemented at Arcelor Research to evaluate the influence of different process parameters on the stability of the flow in the CC mould and on steel cleanliness. The key parameter to improve steel cleanliness is hydrodynamics. It is generated in the mould and naturally unsteady, even if maintaining the process parameters at a constant value. In order to maintain a stable mould flow that allows inclusions removal while avoiding the creation of new defects, process parameters should be optimized or some actuators should be proposed and adapted. The new numerical tool affords a better understanding of the phenomena in the CC mould when some modifications or variations are imposed.

Hardening precipitation in an intergranular-corrosion desensitized alloy, AA6056-T78, is characterized in comparison with that in AA6013 and AA6082 alloys. To extract quantitative information, image-analysis is applied to dark-field images and selected-area diffraction patterns, along with standardless EDX spectroscopy. The central result is that both needle-shaped and lath-shaped precipitates have a similar chemical composition (except for Al content remaining undetermined in this study) to each other and, furthermore, to that of most of the grain boundary precipitates, normally in a more advanced state of precipitation kinetics than those in the grains.

More stringent customer requirements and productivity give steelmakers an incentive to deliver higher surface quality strips. To controland to improve the surface properties, CRM has developed a sensorgrabbing highly magnified images of a moving product. The chosenmethod is based on the principle of triangulation: a very thin line is projected on the surface and the relief is calculated by the analysis of linedeformation. The result is an on-line 3D analysis sensor for assessing topography.

The growing demand for energy, the significant increases in prices offossil fuels and the environmental commitments have led ACESITA toreview its current energy sources and to aim at self-sufficiency in renewableenergy. ACESITA operates two blast furnaces with coke or charcoalas reductant. With the recent investments in the ironmaking areaand in Acesita Energética, and with the combined mastering of blastfurnace operation and charcoal production, ACESITA will be prepared,as of 2009, to operate its blast furnaces with 100% renewable fuel(charcoal). Forest based charcoal production through a modern, environmentally,socially and economically sustainable way is demonstrated.

From a physical chemistry standpoint, the steel industry uses energy and emits greenhouse gases to make steel and byproducts. In the case of slag, which is sold and substitutes for natural resources, ironmaking and steelmaking processes are more efficient. This certainly sheds a new light on the CO2 intensity of products made from slag.

The different activities described by the generic word recycling are presented along with an evaluation of the benefits of recycling in terms of natural resources or energy savings and reduction of Green House Gas emissions. A detailed analysis is presented of steel recycling, by-product recycling and end of life consumer goods recycling. The GHG emissions avoided thanks to sustainable steel recycling are evaluated in a long-term perspective. By-product recycling is also a major issue that has already been addressed with satisfactory results, as blast furnace slag valorization in the cement industry. This exemplifies the cross-business valorization of by-products with strong implications in terms of GHG emissions mitigation. Metal recovery is not yet as fully developed although a fairly satisfying solution is being implemented on the basis of the Rotary Hearth Furnace which separates iron from zinc with production of a DRI and concentration of zinc to a high enough level for direct use by zinc smelters. The future European regulations for consumer goods will require a high level of recyclability that will favour the design with metals instead of other materials such as plastics. Recycling is a complex, rich and fruitful concept that is popular today and will remain strong in the future. It functions both in the market economy and in the administrative world, with by-products moving around the various production shops within a business or between businesses of different crafts. Sustainable recycling is a significant and majority resource for the steel industry which, along with its partners in the recycling loop, has been a pioneer in the world of recycling.

Duplex stainless steels are known to have a good resistance to localised corrosion,especially thanks to their quiet high level of chromium (and for some of them molybdenum),but also because of their very low level of sulphur. These very low levels of sulphur arealso useful to guaranty a good toughness and a good hot workability for these grades.Concerning long products like bars made in Duplex Stainless steels, one of their mostimportant property, after corrosion resistance, is their machinability. Unfortunately, oneof the most known way to improve the machinability of stainless steels is to increasetheir sulphur level, thus forming manganese sulphides in the stainless steels which inducebetter chip breaking and lubrication at the chip – cutting tool interface. So the questionis: can the sulphur well-known way to improve machinability of stainless steels be used onDuplex Stainless Steels, without inducing hot rolling difficulties and too important adecrease of their other main properties, i.e. localised corrosion resistance andtoughness? If not, are other ways possible?

Nanocrystalline oxide ceramic powders are usually metastable and tend to transform into a stable phase during sintering. In this paper dealing with the sintering behaviour of nanosized alumina powders, we present the effects of several parameters on the macroscopic and microscopic behaviours during the pressureless sintering.

The CEQCSI software (Chemical EQuilibrium Calculation for the Steel Industry) was developed at IRSID under the guidance of Jean Morlet. This paper discusses the place of CEQCSI in the fast expanding field of Computational Thermodynamics packages, analyzes the major impact experimentation at Imphy had on its evolution, presents a few examples of industrial applications in ladle metallurgy and inclusions control, and finally evokes trends in the association of thermodynamic codes with CFD (computational fluid dynamics) codes and kinetic models.

In this work, direct potential measurements during cold rolling of zinc and X20Cr13stainless steel were carried out in the rolling slit to follow the tribologic and galvanicmechanisms of hydrogen formation and absorption on the surface of the working rolls madeof DHQ1 grade steel. An Ag/AgCl in 3.5 M KCl reference microelectrode was used to recordthe open circuit potential of the electrochemical system roller-product immersed intocommercially relevant electrolyte (rolling emulsion) with a pH value of 4.5 and anelectric conductivity 46 mS cm-1. The potential shift into either negative or positivedirection of the rolls-product system gives information on the processes taking place atthe surface in the course of the friction. A detailed discussion of the in-situpotentiometry experiments reveals a stationary situation established between thedestruction and repassivation of the surface structures during continuous cold rollingaccompanied with intensive hydrogen evolution. Galvanic coupling of the working rolls withthe product significantly intensifies the hydrogen embrittlement related problems of therolls. Atomic hydrogen is adsorbed on the surface and exhibits a pressure supportedabsorption into the rolls during their whole lifetime.

The carbon footprint is allocated today to CO2 emission sources, and thus to industries with smokestacks, machines with tailpipes or countries burning coal and oil; emission factors are also calculated, i.e. emissions per unit of production, of use, per capita or per unit of GDP. This is, however, not the only way to allocate emissions in a value chain and this could also be done at the source (cradle) of the carbon that will later end up being oxidized. Comparing countries with this new metrics points to fossil fuel producers as the major “cradle producers” of CO2, thus giving a fairly different geopolitical view of the “polluting” world. Beyond issues of responsibilities, related to the polluter pays principle, this new method can help exhibit solutions for mitigating emissions that usually are not imagined or discussed, and examples thereof are given.

During the reactive sintering of W-6%Co-C powder mixtures at 1,500°C under pressure, the reaction product between these elements depends on the relative contents of carbon and cobalt. With a carbon content of 7% by mass, the WC monocarbide forms alone and densification occurs in the presence of a cobalt-based liquid phase. With lower carbon contents, the hemicarbide W2C forms first and reacts with cobalt to form the mixed carbide Co3W9C4. The hardness is increased, but the amount of liquid phase is reduced and the sintering densification is limited. In the presence of the mixed carbide, the cobalt content should be sufficient to be able to produce the amount of liquid phase required for sintering densification. For carbon contents greater than 7%, one obtains the formation of the WC carbide, densified by the cobalt binder, and the precipitation of free graphite. The choice of the initial carbon content allows thus to influence the type of phases obtained and the conditions of liquid phase sintering densification.

The use of stainless steels as concrete reinforcement is becoming increasingly popular incoastal and marine constructions in order to prevent corrosion induced by chloride ionspenetrating into the concrete. In these highly aggressive situations, the lean duplexstainless steels have been extensively employed due to their high mechanical and corrosionresistances. However, the influence of Mo addition on pitting corrosion resistance ofthese steels is not clearly understood in alkaline chloride conditions even if thiselement is widely associated to an increasing corrosion resistance in acidic and neutralenvironments. Therefore, understanding Mo mechanism on corrosion resistance in alkalinemedia is hence of major importance to the setting of optimized alloy composition. Thepresent work aims to study the effect of Mo addition on pitting corrosion properties oflean duplex stainless steels in alkaline environments (concrete). The results arediscussed with respect to the influence of Mo addition on pitting potential for twoindustrial duplex alloys (1.4362 and 1.4462) in several aggressive media mainly insynthetic, chlorinated and carbonated solution simulating concrete pore environments (pH10solution with carbonates and chlorides ions). In order to establish the real role of Moaddition on lean duplex corrosion and passivation properties, the corrosion behaviors oftwo specific laboratory lean duplex alloys, which the only difference between then is theamount of Mo (0 and 3% wt. Mo), are also studied. Furthermore, scanning electronicmicroscopy (SEM) was used to verify which phase of duplex microstructure (ferritic oraustenitic) is mostly susceptible to the pit nucleation in these corrosion conditions asthe role of Mo is probably different to each simple phase.

This article reviews the major aspects of the historical success of the LD process developed in Austria exactly fifty years ago. At the start there are the fundamental considerations of Henry Bessemer and their successful transposition into an industrial steelmaking process. The evolution led to several modern variants of the process, which account presently for a significant part of the world steel production.

There is an increasing need for expanding the scope of traditional life cycle studies toanswer system-wide sustainability questions. This has resulted in a framework for lifecycle sustainability analysis (LCSA). Since the framework was first published in 2009, asone of the outcomes of the CALCAS project, several views and considerations concerning themethodological approach have been published. However, until now practical experience withLCSA is very limited. This paper reports first efforts and experiences in bringing theLCSA framework into practice by assessing the sustainability of solar fuels. Startingpoint of the project is the hypotheses that new technologies can only be practicallyimplemented if they fit into a socially, economically and ecologically sustainablecontext. The analysis therefore aims at identifying performance criteria which a newtechnology needs to fulfil in order to compete in the existing market. It is argued that aLCSA study should be initiated with a broad but relevant system description as the firstof in total five steps Of this five step approach, the first – system description – isdiscussed here. The system description identifies and describes the technologicaldescription, the intended application of a technology, which share of specific demand forservice will be met, which other technologies contribute in meeting this demand, the(relevant indicators for addressing )sustainable impacts of meeting the demand anddevelopments over time. By doing so it provides a solid basis for further steps in theLCSA study.

The main milestones of the development of the modern steel industry are recalled and the changes which have occurred during the last ten years of the 20th Century are examined in the light of the evolution of the economical context in that period (protection of the environment, energy management, development of electric arc steelmaking and of compact and efficient production units, etc.). Several trends for the future evolution of the steel industry are discussed : environment friendly technologies and operations, controlled recycling of scrap, deep modifications for the electric arc furnace, methods for reducing the emission of greenhouse gas, etc.