Clean steel encompasses a multitude of concepts that are based on fulfilling customer requests. Clean steel can be produced in many ways depending on the existing equipment and detailed customer demands. A common feature of all clean steel production is tight process control along with continuous monitoring. Quality assurance is essential and it still requires many improvements. There are no specific obstacles to clean steelmaking, as the industrial processes are available, sufficiently understood and controlled. The major issues to be addressed remain disturbances that occur in industrial reality. This asks for continuous improvements in processes and equipment and for further development of quality assurance systems to achieve full control of any possible detrimental effect.

Transverse cracking may occur in high strength low alloy CC slabs.This phenomenon is associated to a hot ductility trough resultingfrom intergranular ferrite that forms at the beginning of the γ-α transformation. Sumitomo has developed a hot tensile machine and aunique slab surface microstructure control process to improve hotductility. The process based on controlled accelerated secondarycooling has been successfully implemented on Kashima n°2 caster.

For a better understanding of the physical phenomena associated with the appearance of defects in laser welding, a heat and fluid flow model is developed using Comsol Multiphysics®. This first step of the project is focused on the modeling of a static laser shot on a sample of steel. This 2D axially-symmetric configuration is used to study the main physical phenomena related to the creation of the keyhole. This model takes into account the three phases of the matter: the vaporized metal, the liquid phase and the solid base. To track the evolution of these three phases, coupled equations of energy and momentum are solved. The liquid/vapor interface is tracked using the Level-Set method. The calculated velocity and free surface deformation are analyzed. Melt pool shapes are compared with experimental macrographs and the influence of some parameters such as laser power is discussed.

The scarcity and discrepancies in thermodynamic data in Ca andMg containing iron-basis systems is reviewed. The difficulties ofhandling the problems involving these elements in steel with classicalthermodynamic methods recommend the use of computationalthermodynamics. Examples of applications of this method to Caand Mg related problems in steelmaking are presented.

In most cases, hot metal dephosphorization slag is saturated withdicalcium-silicate that forms complete solid solution with tricalciumphosphate;the partition ratio of phosphorous between C2S andliquid slag is large. In order to utilize the effect of C2S phase for theimprovement of reaction efficiency, the optimum route of the slagcomposition change during dephosphorization should be clarified.The results of the fundamental experiments about the phosphorouspartition between C2S and liquid slag from the viewpoints of equilibriumand kinetics are reported.

Maximization of non-coking coal in coal blend is eloquent interest among researchers incoke making throughout the world. To maximize the non-coking coals in coal blend with thescarce and expensive coking coals is an essential practice in the iron and steel industry.The fundamental aspect of the coal blending theory of low value coals to produce goodquality of metallurgical coke in non-recovery coke making process was investigated in thisstudy by using the composite coking potential technique. The implementation of thetechnique has yielded use of up to 25% pulverized coal injection, 20% raw petroleum cokeas a component of coal blend. Results show that the coal blend having composite cokingpotential value of \hbox{$\geqslant $}⩾4.8 is desired to achieve the targeted coke strengthafter reaction of \hbox{$\geqslant $}⩾65.

The recent developments of the Pulse Discrimination Analysis by Optical Emission Spectrometry (PDA-OES) and the application of this technique for static analysis as well as for chemical mapping permit to characterize inclusions or heterogeneities with a size ranging from 2 to 20-30 μm. The present improvements of OES permit the steelmakers to have a more detailed information than by the conventional chemical analysis methods. The fast identification of defects such as inclusions or segregation permits to validate more easily the product quality and to adapt the processes.

Tensile tests on a ultra high strength steel under in situ X raytomography made it possible to observe and to quantify 3Ddamage of this material. The analysis of the data gives accessto the main features of cavities (density and size) as well as localstrains and triaxiality within the whole tensile specimen. Basedon these results, a new damage model has been put forwardthat is noticeable by integrating cavity nucleation into the classicalRice and Tracey approach. The predictions of the newmodel fit significantly better with the experimental results.

The year of 2012 marks the 20th anniversary since the concept of ecological footprint was introduced to the global community for the first time. Nowadays footprint studies have gained extensive debates as well as popularity. In this paper, we define the footprint family as an indicator system of selected footprints that measure some aspects of human impacts on the environment. A relatively comprehensive introduction and comparison of four key footprints is represented by listing their characteristics in different aspects. The interaction among these footprints within the footprint family is classified into three types: overlap, contradiction and complement. The description of each type is provided in detail. Limitations and uncertainties of the footprint family, and priorities for further improvement are also performed. This research makes a preliminary attempt at developing the conceptual framework for the footprint family, which allows us to examine the performance of footprints combination. The footprint family will serve as a tool for integrating footprints on human impacts assessment, and a support for environmental decision-making.

The Hollomon-Jaffe parameter is commonly used to characterize thermal cycles and definetime-temperature equivalences during tempering, but it can only be computed for simplethermal cycles defined by a couple of values [temperature; time]. Its use is not adaptedfor complex thermal cycles. Three tempering parameters which integrate the full thermalcycles were investigated: the Hollomon-Jaffe derivative parameter, and the Tsuchiyama andArrhenius laws. Simple and complex thermal cycles were performed on a water-quenchedcarbon steel (i.e. different heating and cooling rates or two-step cycles, withtemperature varying between 450 °C and 750 °C and times from 30 s to 3 days). All threetempering parameters show good correlation with the tensile properties of the material,even when complex cycles were performed, provided that the material constant is optimized.The sensitivity to the determination of this constant is low for the Tsuchiyama andArrhenius laws: they can be considered as robust and reliable. On the contrary, theHollomon-Jaffe derivative parameter proved unstable.

New dynamic features of the descaling process are reported, referringto the continuous water jet formed by the descaling nozzle in particular.A water jet is formed by clusters of droplets moving at highvelocity. In the impact area, pressure peaks of several hundred MPa,lasting microseconds per peak are observed: this is described as the“water hammer” effect. This finding modifies most existing conceptsof descaling and the impact on current theory is discussed.

SmartCrown is a new technology developed by VAI for a more accurate control of profile and flatness during hot or cold rolling of steel and aluminium. In particular, SmartCrown allows to avoid to a great extent, or even completely, the frequently occurring defect called quarter buckles. The paper highlights the design features of the SmartCrown work rolls and compares the new technique with the well known CVC technology.

Based on results from microscopic analysis of steel samples, flowfield calculations thermodynamic and kinetic considerations, amodel has been derived that describes the evolution of the concentration,composition and size of the inclusions in the liquid steelduring the injection of calcium. The mathematical solution of themodel requires the incorporation of Population Balance Equations.The modelling results are compared to the actual inclusion compositionin the steel from IJmuiden BOS2.

For microorganisms, the preferred living state is adhering to surfaces that can lead tothe development of a biofilm. In drinking water networks, a biofilm can affect theorganoleptic quality of the water as well as whether it is safe to drink. This is due tothe probable presence of pathogens inside the biofilm which may be spread in the water. Tokeep the water quality safe, sanitization processes are regularly carried out usingoxidizing biocides which can alter the physico-chemical properties of the material. Due totheir surface physico-chemical properties and their high corrosion resistance, stainlesssteels seem to be good candidates for the making of drinking water systems. In this 2 yearstudy, stainless steel grades were compared with materials commonly used, in respect offouling, biofilm development and composition. The tested stainless steels include ferritic(444/EN 1.4521), three austenitic (304L/EN 1.4307, 316L/EN 1.4404, and 316LN/EN 1.4429)and two duplex (2304 /EN 1.4362, and 2205/EN 1.4462) grades. The experiments wereperformed in a pilot specially designed to assess the material biocontamination on anatural drinking water loop for more than 2 years. The results confirmed the significantimpact of the material on the biofilm development in terms of formation kinetic andecology. No differences were observed between stainless steel grades whereas theydisplayed an intermediate behaviour compared to other materials. Corrosion attacks wereonly observed on galvanised carbon steel while on stainless steels, negligible releaserates, much below international health requirements were measured. So stainless steelsoffer a good compromise to make drinking water pipes.

Thermodynamic calculations have shown that chlorine can accumulate and cycle in the shaft of the blast furnace in the form of alkalis chlorides. Cycling of chlorine and alkalis in the upper part of the shaft was simulated at laboratory scale with a countercurrent reduction furnace (BORIS furnace) and also directly investigated at an industrial blast furnace. Experiments and calculations have shown the superposition of two cycles: one “pure” alkalis cycle in a large temperature domain, and a KCl cycle in a narrower range (600-1,000°C). According to the trials, effects of KCl on reduction and disintegration behaviour of sinter are similar to those of “pure” alkalis.

The effect of methionine ethyl ester (MetOC2H5), a non-toxic compound on the corrosion of iron in citric-chloride solution at pH = 5, has been investigated by various corrosion monitoring techniques. Results obtained reveal that this compound is a very good inhibitor. Potentiodynamic polarization studies show that MetOC2H5 is a mixed-type inhibitor and that it acts on the cathodic reaction without changing the mechanism of hydrogen evolution. Variation in impedance parameters (Rt and Cdl) are indicative of adsorption of MetOC2H5 on the metal surface. The adsorption of this product on the iron surface obeys a Temkin adsorption isotherm. The effect of temperature indicates that inhibition efficiency of MetOC2H5 slightly changes with increasing temperature in the range of 30-60 °C.

Increasing interest in duplex stainless steels is due to their ability to combineelevated mechanical properties (strength, fatigue...) and an optimal resistance to manytypes of corrosion like Stress Corrosion Cracking or Intergranular Sensitization. Givenhigh chromium content of the standard and super-duplex steels along with molybdenum andnitrogen alloying additions, they also exhibit an excellent resistance to pitting andcrevice corrosion in halide-containing media generally equivalent to austenitic andsuper-austenitic with similar Pitting Resistance Equivalent. Further aspects of thequestion are reviewed in introduction of the present paper including passive film andmetallurgical features such as two-phase microstructure, presence of non metallicinclusions, precipitates or intermetallic phases. Then, this work addresses the problemsof corrosion testing of duplex stainless steels. It is intended in particular to shedlight on some points of practical importance regarding electrochemical characterizationbest practices. Thus, a reliable ranking of materials, including new lean grades, requiresa relevant choice of corrosion criteria and polarization methods. The determination ofboth pitting potentials and critical pitting temperatures is achieved by using acombination of several electrochemical tests based on potentiodynamic, potentiostatic aswell as galvanostatic experiments together with a statistical analysis when needed.

A new technique is presented to recycle ladle slag within the electricarc furnace through the injection system. The dilution of the chemicalspecies contained in the slag and their combination with the speciesfeaturing the EAF slag afford a double advantage: the final slagis structured by chemical species that do not lead to the formationof powders and better stabilize the foaming slag. The industrialresults are analyzed on the basis of the chemical species identificationsupported by thermodynamic modelling.

The developments of plates are strongly driven by demands from high-sophisticatedpipeline and structural applications. Such needs reflect in plates with higher thickness,larger width, higher toughness also at lower temperatures, higher strength and/or betterresistance to sour environments. The requirement profiles are, in some cases, exceptionaland have become achievable, in an extreme combination of alloying and processingtechnologies, only as a result of comprehensive development work and plant investments. Abroad potential for innovation derives by the utilization of the key-technology TMCP(Thermo-Mechanical Controlled Process). The status of present-day heavy plate productionwill be presented. An outline of the production facilities, routes and process variantswill be given. As a central element to achieve high-class requirements, aspects andparameters of the metallurgical design will be explained. The utilization will beexplained and illustrated with selected recent applications.

A new grade of the 200 series has been defined for theEuropean market as a candidate alternative to austeniticgrade EN 1.4301 (AISI 304). The grade was recentlyassigned a material number by VDEh (1.4618 - X9CrMnNiCu17-8-5-2). The paper presents mechanical properties ofthe grade including drawability and corrosion resistancecharacteristics. The newly designed grade has mechanicalproperties slightly superior to those of EN 1.4301 (AISI304) and equivalent to those of EN 1.4310 (AISI 301)grade. In terms of corrosion resistance, the grade is closeto that of grade EN 1.4301 (AISI 304), upgrading theclassical 200 series.