A finite volume computer model of the continuous casting process for steel flat products has been developed. In this first stage, the model concentrates on the hydrodynamic aspects of the process and in particular the dynamic behavior of the metal/slag interface. The model was validated against experimental measurements obtained in a water model apparatus.

The many heat treatments upon fabrication may deteriorate the tensile properties of the tempered base material or to alter its weldability or toughness. It is essential to take into consideration all heat treatments each zone is submitted to: base metal, heat affected zone, weld metal in order to optimize the global properties of the vessel. Major issues are illustrated by precise examples. An approach based on the equivalent tempering parameter is put forward.

The targeted carbide-free bainitic TRIP microstructure have been obtained in the studied steels thanks to a specific alloy-design, following a classical hot-rolling schedule followed with a fast cooling regime and a coiling stage. Excellent balance between tensile strength and ductility are achieved and explained by transformation hardening phenomena. The sharp influence of gamma stabilizing elements (copper/nickel/manganese) on phase transformations and mechanical properties is highlighted.

The addition of boron to steel introduces the possibility of steel initially completely solidifying and then remelting in the interdendritic regions at very low carbon levels. For all carbon levels, a low melting Fe-B alloy exists as a liquid down to around 1100°C. This liquid is found in steel with as low as 0.0004% boron due to the boron segregation. The persistence of this liquid leads to hot shortness, breakouts, and other casting defects. Pseudo-binary phase diagrams for low boron concentrations have been developed using ThermoCalc software and were confirmed using experimental techniques.

A new automated system installed in the ArcelorMittal Asturias steel plant in Avilés, based on novel image treatment, aims at performing an on-line inspection, with feed-back to the process, verifying the effectiveness of scarfing. It detects remaining defects as well as new ones introduced by this operation, thus allowing a quick and reliable assessment of final surface quality.

Asymmetric hot rolling has been found to decrease the rolling loads, to increase recrystallisation kinetics and to refine the grain size. Thereby this rolling practice opens the way to save energy, to decrease hot band thickness, to enlarge formats, to increase strength, to reduce alloying additions and to improve formability.

The new standard EN 14140:2004 permits the use of High Strength Steel grades for the manufacturing of cylinders having a steel sheet thickness lower than the limit imposed by the older EN 1442:1998. The new steel grades proposed for the manufacturing of light weight LPG cylinders have been thoroughly characterized in terms of their in-process behavior.

The relationship between water quality management and the total cost of operation of the steel mill are normally underestimated as areas of relevant cost reduction and productivity improvements. The work that was accomplished on cooling water systems associated with n°4 slab caster at CSN from 2004 to increase significantly steel plant productivity and reduce the total cost of operation is reported.

CVC plus® is a worldwide established and well proven technology package to control profile and flatness in hot strip mills and plate mills. Latest developments of this technology are the application of CVC plus® grindings on work and backup rolls, CVC plus® grindings of higher order and intelligent shifting strategies. The capability of the developments is demonstrated with recent operational results.

Thin organic coated steels have been widely used in the building industry due to their formability, anticorrosive and antifinger print characteristics. In this work paintability properties of these coated steels were studied. Several thin organic coated steel sheets were treated by means of a roll coater following standard procedures (primer + topcoat) and only with topcoat (in this case, the thin organic coating was used as a primer). Characterization tests were carried out in terms of gloss, hardness, adherence and corrosion resistance.

An integrated model developed by ArcelorMittal and NSC to predict the microstructural evolution of austenite in conventional and microalloyed HSLA steels during multi-pass hot rolling is described. The prediction of austenite grain size, recrystallized fraction, residual strain and precipitation state are given. Applications of this model during mono-deformation tests and during multi-pass rolling are presented.

The effect of the so-called “warm” or “ferritic” rolling on the microstructure and recrystallization behavior of LC steels during continuous annealing is reported. The following parameters were investigated; reduction rate in ferrite rolling, coiling temperature; soaking annealing temperature, overageing temperature. Thin gages low carbon steels suitable for replacing conventional cold rolled and annealed steel sheet can be produced.

Nakayama Steel Works LTD. has succeeded in attaining the cooling rate (105 -106 K/s) necessary for amorphous layering technique by using the innovative idea of immediately cooling the spraying flame. Amorphous alloy (Fe70Cr10P13C7) formed by the new technique displays a corrosion resistance more than 500 times higher than the one of SUS316L in aqua-regia immersion test, while the similarly formed amorphous magnetic alloy film (Fe81B13Si4C2) indicates high magnetism of 15.4 kGauss in magnetic flux density.

A review of the degassing process, including basic principles, is done followed by the assessment of castability issues. Steelmaking practices that could lead to potential plugging in the submerged entry nozzles at the casters are outlined. The steel cleanliness is discussed for a select steel grade including a brief review of inclusion characterization.

Very little light gauge steel framing is used for dwellings in Europe. The main reasons are the lack of standards, common procedures and the difficulties to design such structures with Eurocode 3 part 1-3. ArcelorMittal has supported the development of a design tool for low-rise steel framed buildings. The objective is to increase the light steel framing market thanks to a comprehensive and user friendly design package. The tool is based on a clearly defined scope and includes conception rules, design method by graphs and a construction details library.

With extremely high cooling rates, a combined laminar jet and spray nozzle design cooling facility is the most advanced tool for the evolution of mechanical properties of high-strength steels. The main metallurgical aspects of Accelerated Cooling (ACC) and Direct Quenching (DQ) are presented. Typical plate applications are brought up. Design, engineering and operational aspects of modern cooling facilities are explained. Of particular importance for a homogenous cooling process is a powerful process control featuring advanced process models.

Duplex stainless steels present simultaneously very diversified technical challenges and very attractive in service properties along with excellent cost/properties ratios particularly in very critical markets: oil and gas, chemical industry, pulp and paper industry, water systems, desalination plants, pollution control equipments, chemical tankers. This paper reviews the 100 scientific contributions at the latest international Duplex Stainless Steel Conference DSS'07 in Grado, Italy, June 18-20, 2007.

The corrosion risks in a wet flue gas desulphurization system environment are reported. Uniform and localized corrosion resistance of different stainless steels is studied by electrochemical tests. The effects of chloride content, fluoride content, pH and temperature on corrosion resistance are discussed. The results show that duplex UNS S32205 or superduplex UNS S32520 grades are prime substitutes for austenitic 317LNM or super austenitic like UNS S34565 grades in many aggressive environments. The life cycle costs of scrubbers constructed of stainless steels plates or clad plates are compared. The excellent corrosion resistance of duplex and superduplex stainless steels, combined with their increased mechanical properties and moderate alloy cost afford very cost effective solutions for wet flue gas desulphurization.

Stainless steel reinforcement extends the life of concrete, at higher initial costs that may be compensated for by the reduction of maintenance. The effect of several parameters on the galvanic coupling between carbon and stainless steel is reported. It is demonstrated that the introduction of stainless steel rebars do not accelerate the intrinsic corrosion of carbon steel, depending on common rules about surface ratio and number of contact points.

The phase-field method has emerged as a method of choice for the description of microstructure evolution and phase transitions in metallic materials. Following a general thermodynamic extremal principle a set of evolution equations for the structural variables of the system, the so called phase-fields, are derived. The paper reviews shortly the historical and theoretical background of the multi-phasefield method that is an extension of the classical phase-field method to multi-phase multi-component materials. Examples are given from solidification, solid state transformations and grain growth.