Tests were performed on austenitic stainless steels. In order to investigate thermal fatigue resistance of quasi-structural specimens, test facilities enforcing temperature variations similar to those found under the operative conditions have been developed. Multiple cracking networks similar to those detected during in-service inspections have been reproduced. Experiments and simulations deal with crack initiation and crack growth. In the case of multiple cracking simulation, a Skelton's modelling has been used. A shielding effect between cracks is evidenced. It leads to a dramatic reduction of crack growth rate. Such effect is also crucial for the crack network stability under additional loading.

Whereas skimming is a well-known by-product of hot dip galvanizing, it has never been deeply investigated, neither well accounted for, by galvanizers. Physical reasons justify that the proper units, for the operating costs of skimming, are g/m2 or more generally weight per unit surface, instead of weight percentage of the loaded Zn. Indeed, with such a unit, results would largely depend on the average coating thickness. A stepwise regression analysis on skimming, produced daily on four industrial lines of Arcelor, shows that it is highly correlated to the line speed. Skimming costs will inherently increase with the line productivity for a defined thickness. The explanation of that fact is not fully clear because very low Zn oxide is found in the skimming which mainly consists of pure Zn. The wiping process is however suspected. Future work is required to try to establish a full modelling of the skimming production including Fe dissolution as well as the oxidation at wiping and the skimming practice.

The technological package SMART®/ASTC, developed by VAI and already applied in many continuous casting plants worldwide, combines automatic strand taper control (ASTC) with hydraulically adjustable SMART®segments. It allows to improve significantly the internal quality of both slabs and blooms. The principle and working mode of these equipments are described and their multiple benefits are presented.

ThyssenKrupp Stahl operates four blast furnaces with a hot metal production of up to 12 million tons per year in total. To minimize the costs in the cast house operation and to optimize the tapping performance, measures were taken to prolong the lifetime of the refractory lining of the troughs by a supreme effort. Extensive technical measures in the total cast house area with the aim of best economical efficiency were taken. This report shows the effects for the cast houses of the big Schwelgern furnaces.

Companhia Siderúrgica de Tubarão (CST) has been making intensive efforts to increase the slab production and to maintain a stable level of 5.0 million tons/year. In order to achieve these objectives, it is essential to consider the ability to produce narrow width slabs, 750 ~ 1,050 mm, using twin casting technology. This paper describes the main aspects associated with CST's twin casting process, operational and quality problems faced during the first heats produced, as well as the action plan used by CST to overcome these problems.

The part-bath heat transfer coefficient during a quenching operation is particularly important in order to simulate the workpiece hardening. The estimation of this coefficient requires specific developments in the field of instrumentation. This paper presents an experimental methodology which was developed within the laboratory. Experimental results are compared to numerical simulations using a heat transfer coefficient obtained from experimental estimation. This comparative approach allows to validate the experimental methodology and also to ensure that the tested pieces are representative.

The automobile is still the favored means of locomotion in Europe. Easy to use and a freedom satisfier make it indispensable in our daily lives. And yet the car is at the same time accused of playing a major role in atmospheric pollution and global warming of the earth by the greenhouse effect, being the main source of harmful noise and danger, and thus obliging lawmakers to react and make it evolve under regulatory pressure. The purpose of this article is to determine the current situation and posture in terms of law and regulations concerning it and to describe the solutions offered by steel.

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.

Precipitation hardening in lead-cadmium-calcium alloys is a two stage process: the first stage is a discontinuous hardening transformation without precipitation, the second stage is a discontinuous lamellar precipitation of Pb3Ca. In order to increase the mechanical and electrochemical properties of these alloys, we have studied the influence of minor additions of tin on the precipitation hardening behaviour of PbCaCd alloys, as this element is used to improve the electrochemical properties of positive battery grids. The objective was to investigate in a systematic manner the ageing and overageing behaviour of PbCdCaSn alloys in the case of two different structural states: as-cast condition, rehomogenized state.

The mechanism of zinc wettability defects on high silicon and high aluminium annealed steels has been studied by transmission electron microscopy of specimens prepared from synthetic steels recrystallized on a simulator. Wettabillity defects on high silicon steels are associated with a continuous amorphous silica layer that forms during annealing. On high aluminium steels, wettability defects result from a continuous crystallized alumina layer thicker than 6 to 8 nm.

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 solid flow inside a blast furnace is modelled using a stand-alone finite element program and a constitutive equation called hypo-plastic, in order to better simulate the granular material behaviour. The parameters of this constitutive equation are calibrated using data obtained from simple soil mechanics tests on coke and sinter materials, such as triaxial and oedometric devices. Steady velocity, stress and void fraction fields are obtained after several iterations of the code. Knowledge of the solids velocity field makes it possible to determine the dead man profile, as well as its renewal kinetics. Burden trajectories and time lines are also computed. Knowledge of the stress field makes it possible to compute pressures acting on the burden as well as on the walls. Finally, the knowledge of the void fraction field makes it possible to determine gas paths. The solid flow model was validated on 2D and 3D small-scale cold blast furnaces, but the simulations never required any tuning parameter. This code is in fact an invaluable tool to determine the effect of blast furnace profile on solid flow conditions, and vice versa.

As main goal of the upgrading project of its heavy plate mill, voestalpine Grobblech made various improvements on the rolling mill, but most of all replaced the complete mill automation system. As the rolling process is performed almost automatically, the operator can concentrate on quality observation and throughput aspects. The modernization project also concerned the hot leveller in view of improving quality, extending the range of product dimensions and renewing the automation system. A new setup model was installed.

In Valchiusella, near Traversella on the left side of the Chiusella river, some rivets in steels were found and they can be dated at the end of the 18th century and the beginning of the 19th one. The chemical analysis has pointed out that the steel is very poor in carbon, but in the essentially ferritic structure, some significant pearlitic zones have been observed by metallography in the core of the product, as it could be expected if a forging carburizing treatment was applied. Some fragments of entrapped slags have been detected within the analyzed steel products and have been chemically analyzed by EDS as well as the slags found in the rivet and the non-metallic inclusions of the steel. The chemical composition of the non-metallic compounds has been investigated by the software ThermoCalc. The data obtained have been compared with the results of the metallographic analysis of the steel. The thermodynamic conditions for the production of the investigated steels have been underlined in order to improve the knowledge of the features of the reduction process used during that period.


Poly(vinylidene fluoride) (PVDF) thin films were subjected to tensile tests in plane strain over the temperature range from 65 to 115°C. At different elongation velocities using video real stress and strain, it was observed that, under such strain regimes, the neck-in starts perpendicular to the tensile axis and propagates towards the sample ends. The propagation kinetics was carefully recorded during the tensile tests. It was shown with simple hypotheses, that essential plasticity equations of the material can be determined via this method in terms of local effective stress (σeff) as a function of local effective strain (εeff) for every investigated temperature. The X-rays diffraction shows that the stretching of the sample of PVDF at a temperature lower than 72°C causes the transition from phase II to phase I.

For the production of steel with an EAF (especially, also, for stainless steel, as shown at CORUS Engineering Steels in Stocksbridge), the RCB system of VAI FUCHS (Refining Combined Burner) represents an important step forward, in many respects, for the injection of oxygen. The constitution of the system, its working mode and its advantages are described. This innovative solution is already applied in the case of quite a number of furnaces.

An automation project has been realized to raise the capacity, the logistic and delivery performances, to reduce the workforce needed and to optimize the use of transport vehicles. This project comprises automatic tracking of all slab displacements, done by overhead cranes and other transport vehicles. It also contains algorithms to generate optimized slab displacement commands. The position tracking of outside transport vehicles is done by GPS. The optimization algorithms will be described in some more detail, as well as the results of the complete system.

The major changes that have occurred in the steel industry are described along three periods: the thirty years boom-period after World War II; the zero growth period (1973-1983); the last period, from 1983 to nowadays. Under the heavy influence of the overall trends of world economy, these periods can be distinguished, for the steel industry, by the different levels of priority for productivity, for specific flat carbon steel product developments or for environmental protection. The intricate relations that prevail between the development of new processes, innovative product metallurgies and the requirements expressed by steel customers are highlighted.

In the European market for packaging steel, 50% is used in the food sector. Developments in canmaking and canning generally concentrate on process improvements, lightweighting and higher efficiencies. This is achieved by small process changes, but this evolutionary approach is not the optimum. Another option is the revolutionary approach. Concentrating on customer value, new products and processes should be developed. Developments in sterilization and packaging, and possibilities for new packaging designs are discussed. Calculations on the sterilization process have been carried out, concentrating on the amount of biological kill, but also considering final food quality. New options for value creation through innovation, complying with value chain requirements, are discussed.

In close collaboration with its customers, Arcelor has developed new hot rolled steel grades for single-face and double-face enamelling. These new grades, that fulfil the most stringent market requirements, are produced in several plants of the Arcelor Group. Their outstanding properties are obtained by the through-process control of precipitation phenomena, including steelmaking, hot rolling and cooling. Particular attention is paid to the addition of strengthening elements, such as Mn, Cr, and Nb, for high strength grades. The enamelling ability and the mechanical properties of these new hot rolled grades are presented in this paper.