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.

Because of the effects that they produce, grinding operations may modify significantly the surface of a material and change its properties. The major part of the plastic work of cutting is tranferred to the part being ground as heat. In the case of the austenitic stainless steel studied here, grinding leads to an increase in hardness which can be attributed to the superficial plastic deformation of the material. However, for the most severe grinding conditions, a change in the deformation process is observed leading to dynamic recrystallization. This process is characterized by grain growth and dislocation rearrangement under the combined effect of the temperature and the stress level reached during grinding.

Insuring stable supply of wide-width quality slabs for HR/CR automotive and API applications was the main reason for revamping the Posco Gwangyang No. 1-3 machine that is, incidentally, the only large-width slab caster (up to 2,000 mm) in operation at Gwangyang Works. To meet that objective, both at the surface and internal quality points of view, several technical advances were included in the project such as: vertical-bending, multi mode electromagnetic stirring in the mould (MM EMS), hydraulic mould oscillation (DYNAFLEX), split and short-pitch strand guide rolls, soft reduction (ASTC) and dynamic secondary cooling control (DYNACS).

From a Finite Element analysis, the stress distribution in the notch of axisymmetric and highly loaded notched samples has been calculated. The samples are shaped like a thread root. We propose a simplified method of sizing screws for a large range of mean stresses. So, a local Haigh's diagramm at the thread root is built from the Haigh's diagram derived from smooth or notched samples.

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.

The authors introduce the multi-scale modelling approach of service properties and recent results that best reflect the complex behaviour of industrial materials. They describe the main modelling tools and highlight the essence of experimental checking at the appropriate scale. The authors describe in details the progress that has been accomplished in the prediction of the energy of atom-scale defects in steels, as essential input data to model the kinetics of microstructure evolutions under radiation. The authors present the multi-scale prediction of mechanical properties along with the particular issue of the nuclear fuel.

50 years ago, ECSC programmes have introduced collaborative scientific and technical research on a European scale. They have created the foundations for the European Research framework programmes (FP). The ECSC treaty has expired. A new research programme, complementing the FP of the European Union: the Research Fund for Coal and Steel, is born. The Steel Technology Platform will secure its full coordination with all other available steel research instruments. All of this constitutes a very tangible and lively legacy of the ECSC, in a more global world, in the light of new priorities of the European Union, of the objectives of Lisbon and Barcelona, and finally of the today reaffirmed strategic importance of the knowledge-based economy.

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.

After two previous reconsideration steps on cathodic charging and hydrogen stress cracking, then permeation measurements, a third step is presented on the SOHIC mechanism, and more generally any interaction between internal hydrogen and moving dislocations. This results in a unified mechanism for all forms of hydrogen damage, built ex-nihilo from the mere data on metal electronic structure, the physical state of the H+ ion in water, steel micrographic structure and dislocations movement. There are already many practical and theoretical consequences.

VOEST-ALPINE Industrieanlagenbau (VAI) has developed highly efficient systems for the removal of dioxins from the offgas of conventional electric arc furnaces, as well as of shaft furnaces. These systems have been successfully implemented at industrial scale. This paper describes the components and working principle of these systems and gives information on the achievable emission levels.

Recent investigations have shown that an iron oxidation / reduction process can improve the quality of the coated steels by decreasing the amount of external selective oxidation. This economical process can be made during heating by modifying the air/gas ratio of the direct fire furnace or in the rapid cooling section by air injection. A sensor allows measuring continuously the iron oxide thickness of the oxidized strip.

This project was developed in order to keep the production of the CST Continuous Casting No. 2 steady at 2.8 Mt/year. The main focus was the reduction of segments failure that was caused by short life of bearings, a forth of the time expected. The goal established was well overreached due to a set of improvements made by operation, maintenance, technical unit and engineering: reduction of the number of break-outs; improvements on control and raise of casting speed.

Kwangyang has been operating five large size blast furnaces and K-1 BF was relined in March 2002 after finishing 15 years of operation successfully. To secure enough cast pig iron as one of countermeasures to a low HMR at the steelmaking process during the relining period, four other blast furnaces came to increase their productivity in advance, before the start of the K-1 BF long stoppage. Particularly, during the ultra-high productivity operation period from March to June, K-3 BF marked a new POSCO productivity record and a new silicon record simultaneously on May in spite of unstable sinter consumption due to the width extension of No. 1 & No. 3 sintering strands and 13 years furnace life. It was 2.76 t/day$\cdot$m3/IV in productivity and 0.15% in silicon level in pig iron. These remarkable records were based on some advanced Kwangyang BF know-how and recent developments like higher facilities reliability, optimum allotment of hot blast and oxygen, high sophisticated burden distribution control and special screening equipment of raw materials.

For today's investments, quick pay-back is becoming more important than ever before. The market increasingly demands the shortest possible delivery times and correspondingly greater flexibility of production. Minimal shutdown times as well as a fast start-up curve during start-up or restarting of the plant have become an absolute necessity today. A new plant concept is illustrated by the extension project of an existing Steckel mill with three finishing stands in tandem arrangement to increase its annual production. Furthermore, the quality of the products will be clearly enhanced thanks to the modified process and the selected technology. In order to implement all this with the highest possible commercial benefit, a revolutionary revamping concept, which reduces the mill shutdown period to a minimum, is introduced to the market. The so-called “add on products” have been developed to generate the highest possible benefit in existing facilities with limited expense and effort. Highlights include the differential tension looper and the tensiometer looper, the compact cooling system, edge masking as well as the on-line polisher.

In order to decrease the silica content in 16% Cr ferritic stainless steel, the phases present in deoxidized inclusions were predicted by the FACT model. To decrease the amount of deoxidized inclusions and slag inclusions in the melt, the capacity of alumina absorption was compared using different top slags. In trial tests, the cleanliness of slabs was significantly improved in 16% Cr ferritic stainless steel produced by AOD processes and the number of surface defects of cold coils was also significantly reduced.

Transmission and reflection measurements using synchrotron radiation have been performed on a Ni sample submitted to tensile stress. For each studied crystalline plane, the strain was determined from spectral analysis of the diffracted beam, with a precision in the range of goniometric X-ray analysis. Apparent elasticity characteristics were then deduced assuming plane stress state on the surface and plane strain state in the bulk. The high elasticity modulus at the surface compared with the bulk one could be explained by a roughness effect or a lower yield stress near the surface.

This article studies the creep behaviour of the Ni/NiO system at 550°C under oxygen. Several phenomena of damage appear during the deformation in creep. These damages are in situ highlighted and separated with the help of the acoustic emission technique. These results are post-mortem confirmed by various standard techniques. Possible effects of interaction between the mechanisms of deformation and the degradation behaviour were also examined.

The Steel Industry today is a large and capital-intensive industry, which has reached a high level of sophistication, complexity and efficiency. This benefits the consumer, as the price of steel has been steadily decreasing, which helps bring down the price of consumer goods. Steelmaking has therefore become focused on a small number of process routes, which connect together standard, mainstream and high performance technologies. It seems therefore that the industry is very mature and that little leeway is available for change, as past progress has already brought it close to physical limits. This is a view of the Steel Industry, which is contemporary and central to the strategy of this business. A Steel Mill that does not operate within the paradigms of the mainstream state-of-the art technologies will be doomed by economic troubles and eventual bankruptcy. However, Steel or Iron have remained at the core of civilization for roughly 3,000 years and the model of the Steel Industry discussed above is only roughly 30 years old. There have been many more different models in the past, from Prehistory to History, and it is likely that even more will emerge in the Future. Indeed, it is reasonable to assume that Iron and Steel will continue to be used for a very long time. The present paper discusses Steel from the standpoint of an Enduring Material and the Steel Industry from that of a Cumulative Technology and explores how these two important concepts have led to industry changes in the Past and will most likely contribute to more changes in the Future.

Samples of AISI 304 steel with layers nitrided at low temperature (< 450°C) have been heated isothermally under neutral atmosphere for times ranging from 4 to 3,000 h. The stability of the layers varies depending on holding temperature. At temperatures greater than 450°C, the initial FCC disordered metastable solid solution, supersaturated in nitrogen ($\gamma_{\rm N}$), decomposes in a relatively short time (4 h). At lower temperatures, however, no change in supersaturation and no decomposition occur, even for holding times exceeding 3,000 h. Nevertheless, an increase in layer thickness is noted and the hardness within the layers remains high (800 HV10).