Most steel grades undergo a ductility trough in the temperaturerange 700 to 1100 °C that may bring about surface cracks in the CCstrands.
Micro-mechanical modelling of the as solidified austenite-ferritemicrostructure, supported by experimental evaluations of the fracturesurfaces, affords a comprehensive description of the crack formationmechanism. This opens the way for a quantitative evaluationof the sensitivity of CC strands to transverse cracks.

The coefficient of friction is one of the tribological factors that characterizethe process of multi pass hot rolling. Friction is strongly dependenton inter-pass and in-pass rolling and cooling processingparameters. It can be improved by application of hot lubricationunder specific conditions. This paper builds upon previous studies onthe application of a Coulomb-Norton friction mathematical model, tostudy the influence of hot lubrication for a range of rolling conditions,with a view to define conditions where lubrication is most effective.

As a substitute for the chromate conversion anticorrosive systemCRM has developed a new conversion coating based on silica nanoparticles.This new process will be implemented on galvanizing linesjust after the zinc bath where the metal strip is still hot. The strip isdipped into a batch containing a suspension of these nanoparticles.Thanks to the strip heat, the solution is locally destabilized and thenanoparticles precipitate onto the metal. The result is an ultra-thincoating (50-200 nm), very compact, that can provide excellent paintadhesion and anticorrosion properties.

The FSBA (Flexible Shaft Backing Assemblies) has been developedfor a 20-high Sendzimir mill. This new shape control actuator wassupported by a shape analysis model based on the distribution ofgeometrical moment of inertia in the roll axial direction. The shapecontrol range was doubly extended by the introduction of FSBA. Itwas confirmed on an industrial mill that quarter buckles are suppressedunder a wide range of rolling conditions by shape control withFSBA and concave rolls.

Dynamic modeling, as an effective decision support tool, is illustratedby the coupling of two continuous lines. The method stands outas general and easily transferable. Modeling makes it possible toassess the impact of various managerial decisions within a globalindustrial environment. Modeling is a preferred tool to extract knowledgefrom data bases, to formulate and to test new ideas.

We propose a model for predicting the kinetics of cementite dissolutionand austenite growth during heating and soaking. This modelis applicable to multi component systems and a good agreementbetween the calculations and experimental data were obtained. Thismodel is coupled with a mechanical module which allows taking intoaccount the various effects of cold deformation on the kinetics ofaustenite formation during heating and soaking. A discussion ismade from a 3D microstructural investigation.

Use of stainless steel rebar for concrete reinforcement is increasingworldwide. The enhanced properties of stainless steel prove to be aviable solution when life cycle costs of the structures are taken intoaccount. Austenitic and duplex stainless steels are used as rebarbecause they present an excellent combination of corrosion resistancein concrete, high strength and good ductility.
The resistance to pitting corrosion of various stainless steels hasbeen evaluated by electrochemical tests. Thus, it is possible toselect the appropriate grade according to the environment the concretestructure is submitted to during its life. A classification of theselected austenitic and duplex grades is introduced.

An automatic detection system for edge cracks and holes has beensuccessfully installed at the exit of the tin plate mill of the API Basse-Indre plant. This new system is able to detect, analyze and recordimages of any defect that may be dangerous for the CAL. Since thesystem has been implemented, Basse-Indre has recorded no breakageneither in the furnace along year 2005, nor at entry, at exit or inthe furnace since early 2006.

Thickness defects on thin strips are caused by the cold rolling processitself or by mechanical trouble at the tandem mill. Dedicatedexperimental measurements of the related phenomena are reportedand a global analysis of their effect on the final product thickness isput forward. Innovative advanced solutions are presented to achievehigh thickness performance.

The current strong demand for vehicle lightening from the automobilesector requires flat carbon steel manufacturers to develop newadvanced grades capable of fulfilling the increasingly stringent technicalrequirements of this market. Arcelor Research has recentlydeveloped an ultra high strength Fe-Mn-C austenitic steel with excellentformability for automotive applications. The X-IPTM1000 steelcomposition is optimised to provide the best compromise in ultimatetensile strength (>1000 MPa) and total elongation (>50%) at roomtemperature. These properties are achieved through the optimisationof the TWIP (TWinning Induced Plasticity) effect by careful control ofthe stacking fault energy (SFE) and the final microstructure.

Critical parameters that affect both the ferrite grain size and the precipitation kinetics during hot rolling Nb-bearing steel were studied.Accelerated cooling was applied after the last pass of finishing rolling.In all cases the Nb(C,N) precipitation was strongly retarded, increasingthe precipitation hardening by the formation of fine precipitates.Moreover a non-negligible amount of Nb remained in solution. Nb(C,N)precipitation occurred during annealing cold rolled steel, causingsecondary hardening.

LABEIN and ACB have developed a model to predict the mechanicalproperties of the hot rolled products, considering as a first stepthe hot rolling of thin slabs on the 7 stands hot strip mill (thin slabdirect rolling) of the Sestao steelworks.
The thermomechanical model includes a thermal module and adeformation module. It is supplemented with a microstructuralmodule and a mechanical properties module. The model has beenvalidated versus industrial results. It also includes an optimizingmodule that makes it possible to define the most appropriate processevolutions to meet new product requirements.

The features of dynamic transformation for grain refinement of lowcarbon steels are presented and representative results of trial hotstrip productions are reported. Laboratory experiments have establishedthat dynamic transformation occurs in under-cooled austeniteunder suitable deformation conditions. Trial production resultsshowed that utilizing the dynamic transformation concept, grain refinementof ferrite is feasible in commercial hot strip mills: a ferritegrain size of 2~3 μm can be obtained, along with various controlledsecond phases.

Civil engineering structures may suffer accelerated damage from thecorrosion of their carbon steel reinforcement bars. This corrosion originatesfrom the carbonatation of concrete that lowers the pH andfrom the diffusion of chlorides through the concrete. It generatesheavy maintenance and repair costs and it significantly reduces theservice life of the structures. These consequences can be avoidedwith the general or partial use of stainless steel reinforcement bars.This solution affords many advantages:
Significant reduction of the maintenance costs.Increased sustainability.Reduced service costs.Improved safety.Optimized concrete thickness.
The limited extra cost of stainless steel rebars over carbon steelrebars is quickly overcompensated for by the savings that they allowon maintenance costs.

Stainless steel forming processes require simple laboratory simulation tools to save production costs. Although reliable numerical tools are available, there is still a need for appropriate constitutive laws. Stainless steel is characterized at high strain rates with an instrumented impact test machine. This allows determining the rheological parameters of different grades to be fitted in a simple constitutive law. Accurate results are thus obtained that afford an effective simulation of the stainless steel forming process with FE-analysis (Forge3).
This is illustrated with the development of a new austenitic stainless steel grade for cold heading applications.

In 2000, ACB decided to double the capacity of the thin slab casterand of the hot strip mill with a view to substitute ultra thin hot stripfor conventional cold strip on the market. To cope with the extra tonnage,a new pickling line had to be installed. The main features of thenew pickling lines that makes it possible to process thin gauges atreduced total costs, are presented.

As a result of the demand for increasing the operating life of aeronauticparts, it is sought in this work to optimize the mechanical characteristicsof a bearing submitted to marine environment.Phase transformations during high speed austenizing have beenstudied together with the influence of thermal stresses due to inductionheating. It is observed that there are two ways to obtain the bestmechanical properties among which the shortest cycle could beused to reduce heat treatment time of highly alloyed cold worksteels.

A mortality study was carried out among workers employed in theArcelor and GTS Industries plants in Dunkerque. It was aimed atassessing the possible association between iron oxide exposuresand lung cancer risk. The cohort comprised 16,742 males and 959females. Among males, the observed mortality was lower thanexpected for all causes. No significant lung cancer excess was observedfor exposure to iron oxides and no dose-response relationshipwith intensity and duration of exposure.

In order to improve the safety and reduce plant shut down time forscheduled maintenance works, Aceralia is developing and testing onits HSM at Aviles an application that ensures that the selected equipmentis correctly and safely powered down. This application also servesupdated information regarding the current status of maintenanceworks and equipment. Finally, it performs automatic analysis of theevents happened during the shut down, deviations with respect tothe scheduling and other statistical analyses.

With increasing boron content, the coarsening rate of M23C6 carbidesbecomes reduced near grain boundaries in tempered martensitic 9Cr-3W-3Co-VNb steel during creep at 650 °C. This retards the recovery ofmartensitic microstructure up to long times and increases long-termcreep strength. However, excess addition of boron and nitrogen causesthe formation of large amount of massive boron-nitrides during normalizingat 1050-1150 °C, which significantly decreases the boronconcentration available for microstructure stabilization and degradesthe creep strength.