Existing rolling mills entering the markets for high quality steel may be limited by their descaling systems installed in terms of pressure and flow rate. In addition to the potential for optimizations of existing systems, the potential for optimization of the nozzle design itself has now been fully utilized in order to maximize the impact at a given water flow and pressure. New design methods and production technologies have been applied.

The hot ductility of Ti-bearing steel was studied by theoretical calculation and athermal simulation experiment. Meanwhile, microsegregation and precipitates were analyzed.The results showed that the S, P and O elements were enriched at the grain boundaries,while the hot ductility was deteriorated by inclusions of (Fe, Mn, Si, Al)(S,O) in theinterdendritic region. At a temperature of 1300 °C, large TiN particles have little effecton the hot ductility. In the temperature range from 1000 °C to 900 °C, the Reduction ofArea (R.A) declined rapidly from 81.77%to 31.77%, with the size of particles decreasing from 5 to 20 nm and quantity increasingfrom 1.2 inds/μm2 to 354 inds/μm2,respectively. In the temperature range from 900 °C to 850 °C,R.A decreased from 31.77% to 30.12%with the ferric films gradually thickening. The critical stress, 63.58 MPa, was equal totensile strength at 912 °C. Intergranular fracture occurred easily with higher criticalstress below 912 °C.

Carmakers face ever more frequently the phenomenon of spring-back after stamping, especially with new high strength steels (HSS and VHSS). Renault and Arcelor have been working together for many years on the formability and spring-back of VHSS. Recently, they aimed at establishing a method to optimize die shape in order to compensate for the spring-back after stamping. A method, named “Outifo” has been developed in order to obtain by simulation, from the initial CADs of the part and its referential stamped die, a CAD of a die with a modified shape. This allows the real stamping part, after forming and spring-back, to recover as closely as possible the geometry of the theoretical part defined by the designer.

The applications of vacuum treatments for coating metals are recalled. The surface preparation, which is essential for any efficient deposition process, is first examined. The main vacuum coating techniques are described in detail, with the emphasis on technologies actually used in tndustry, with their advantages and disadvantages. Examples of the industrial application of this process are given and their economic importance discussed.

The application of finite element techniques to modelling the longproducts rolling process, the use of a customized interface to enablethe rapid set-up of sequential simulations, and the benefits thathave been obtained are described. The paper also discusses theenhancements to incorporate a design of experiments/design optimisationmodule and to enable material tracking.

The accuracy of the parameters is of great importance in the calculation and simulationof the COREX process. Therefore, it is necessary to measure some parameters, especiallythe heat loss and its distribution, which have not been reported before. Based on thecharacteristics of the two sets of the Baosteel COREX-3000 process, a method and standardare established for the heat loss and its distribution. Then the heat loss anddistribution are calculated based on the measured parameters. The results show that thetotal heat loss of the two COREX processes is 495.4 MJ/tHM and 413.7 MJ/tHM. The heat losscaused by cooling water accounts for more than 93% of the total heat loss while the heatloss of furnace shells is less than 7%. The main heat loss caused by cooling water takesplace at the tap hole zone, which is also the part of the COREX system with the most heatloss Its heat loss is about 30% of the heat loss caused by cooling water and 28% of thetotal heat loss of the COREX system. The main heat loss of furnace shells takes place atthe dome of the melter-gasifier and the reducing gas entrance position of the shaftfurnace, where the heat loss accounts for nearly 90% of the heat loss of furnace shells.It is also found that the energy utilization efficiency of the 1# COREX system is muchlower than that of the 2# COREX system after comparison.

CPM developed a mechanical sensor to measure coke oven wall deflections. This sensor was used in Dunkirk coke plant under normal operating conditions and showed reversible deflections between 1 and 1.5 mm when plastic layers meet at the oven centre. Special blends, with a high content of low volatile coals, were charged in several ovens of the Drocourt coke plant. In those conditions, CPM noticed the same phenomena as in Dunkirk plant but also reversible wall deflections just after charging.

“Stand-support sintering”, that is supporting the load of the sinter cake with bars or plates attached to pallets, has been developed and applied practically to the sintering machines in Kimitsu works, Nippon Steel. The stands start to support the load of the sinter cake just after the top layer is melted and starts to solidify. Shrinkage is stopped and the gas flow rate is increased when the stands start to support the load of the sinter cake. It was found that sintering time was shortened and productivity was improved in actual sintering machines.

Today, the numerical simulation of fluid dynamic phenomena(CFD) in steelmaking applications is state of the art. Thelatest simulation results for the BOF and AOD as well asthe thin strip casting process are described. The basicinfluence of the process parameters, e.g. blowing andstirring rate, vessel dimension, location of top lance, numberand arrangement of porous plugs, on the converter meltflow and mixing time is simulated. In the case of thin stripcasting, the free melt flow on the moving belt is influencedby an induced electromagnetic field. The respective MHD(magneto-hydrodynamic) is presented.

The topography of grain boundary thermal grooves in the Ni-rich NiAl is studied by the atomic force microscopy. It is demonstrated how the processes of grain boundary sliding and surface faceting modify the shape of the grooves. The quantitative theory of grain boundary grooving that takes into account the above complications is developed. The great potential of grooving studies for the analysis of microstructure evolution is emphasized.

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.

This article tells in the form of a tribute to chairman René Damien, the founder of Usinor, the story of the French wide strip mills. The situation of the French steel industry in the 1950s is first recalled. The important decisions made to modernize this industry are then presented and the major milestones of the construction and operation of the hot strip mills of Denain, Serémange, Dunkirk and Fos are indicated.

In Europe, like elsewhere, the share of steel produced by electric arc furnaces from scrap increases. As the amount of internal scrap has decreased considerably, the steel plants recycle more and more collected obsolete and capital scrap. This source of iron has increased rapidly and will continue to increase. In spite of that, some plants may have to include in their EAF charge prereduced iron coming from countries where natural gas is available at low cost.

With extremely high cooling rates, a combined laminar jet andspray nozzle design cooling facility is the most advanced tool forthe evolution of mechanical properties of high-strength steels. Themain metallurgical aspects of Accelerated Cooling (ACC) andDirect Quenching (DQ) are presented. Typical plate applicationsare brought up. Design, engineering and operational aspects ofmodern cooling facilities are explained. Of particular importancefor a homogenous cooling process is a powerful process controlfeaturing advanced process models.

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.

Statistical methods have been used to analyze the thickness variations in coils of packaging steel. A sampling procedure has been defined in order to characterize the thickness variations in length and width directions for a given coil and from coil to coil. The analysis has allowed to evaluate the respective contribution of the various sources of scatter in relation with the production sequence and to define a strategy for the improvement of the results in this area.

Deux grandes classes de procédés ont été employées par les forgerons d’aciers dès lepremier millénaire av. J.-C. A partir de deux exemples typiques nous montrons commentl’interprétation des examens métallographiques avec des outils modernes tels que MEB etMEBFEG permet de reconstituer ces techniques. Un échantillon de l’époque mérovingienneillustre la fabrication de lames figurées par multiples opérations desoudage puis forgeage. Un échantillon de wootz prélevé dans une lame du XVIIIesiècle illustre le forgeage du fameux acier fondu de Damas.

The performance of lubrication systems for cold double reductionrolling has been investigated. Pilot mill trials have been achievedwith direct and recirculated emulsion application as well as with pureoil to analyse the effect of lubrication by emulsion on role bite frictionand the associated speed effect. It is then attempted to define anoptimized lubrication system that combines the advantages affordedby the direct and recirculated application systems.

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.

The selective oxidation of three CMnSi steels with differentC levels was studied by XPS. The formation of a graduallycovering SiO2 film is observed until a transition temperatureabove which the oxide film disappears, resulting in a renewedappearance of metallic iron at the surface. This change inoxidation behavior is thought to be due to the SiO2 reductionby solute C which is thermodynamically favorable at hightemperature. At the same time the precipitation of a BN filmon the metallic surface was observed which prevented anyfurther oxidation.