ARCELOR Research

Paris, France

ARCELOR Research

Paris, France
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Thebault F.,University of Burgundy | Vuillemin B.,University of Burgundy | Oltra R.,University of Burgundy | Allely C.,Arcelor Research | Ogle K.,École Nationale Supérieure de Chimie de Paris
Corrosion Science | Year: 2011

A finite element model (FEM) was developed to calculate the potential distribution in the electrolyte in the case of bimetallic corrosion between iron and zinc electrodes, taking into account mass transport of oxygen in the solution. This model was first compared with experimental results obtained by scanning vibrating electrode technique (SVET) on a galvanized steel cut-edge in immersion conditions in a 0.03. M NaCl electrolyte. A good agreement was obtained between the calculated and experimental current densities. The model predicted the evolution of the galvanic coupling as function of the electrolyte thickness and for various iron-zinc surface area ratios. Different coupling regimes were highlighted when the electrolyte thickness was decreased: from a kinetic (cathodic) control in full immersion conditions, to an ohmic control for very thin electrolyte films, leading to a decrease of the protection efficiency. The evolution of the critical electrolyte thickness limiting these different regimes as function of the conductivity and geometrical conditions was also studied. © 2010 Elsevier Ltd.


Thebault F.,University of Burgundy | Vuillemin B.,University of Burgundy | Oltra R.,University of Burgundy | Allely C.,Arcelor Research | Ogle K.,École Nationale Supérieure de Chimie de Paris
Electrochimica Acta | Year: 2011

Electrochemical processes occurring on the cut-edge of a galvanized steel immersed in NaCl solutions were studied using numerical simulations, and in situ current and pH profiles measured over the cut-edge. These results clearly demonstrate that only the steel surface remote from the zinc coating is cathodically active, oxygen reduction being strongly inhibited in the vicinity of zinc. This trend was confirmed by local polarization curves recorded on these distinct areas. Ex-situ AES and SEM analysis and cathodic polarization curves in solutions containing Zn 2+ ions led to conclude that this cathodic inhibition was related to the fast nucleation of a dense Zn(OH) 2 film on the steel surface. After a long term exposure, a new galvanic coupling takes place between the Zn(OH) 2 covered area, showing an anodic activity, and the remaining steel surface covered by bulky white zinc corrosion products. © 2011 Elsevier Ltd.


Bareggi A.,CNRS Contacts and Structural Mechanics Laboratory | Maire E.,INSA Lyon | Bouaziz O.,Arcelor Research | Di Michiel M.,European Synchrotron Radiation Facility
International Journal of Fracture | Year: 2012

Damage in a dual phase steel was measured using in situ high-resolution X-ray absorption tomography. A comparison with the behavior of its two constituents ferrite and martensite, taken separately, was also achieved in the present work. The method was particularly useful for analyzing the respective contribution of nucleation and growth of voids in the studied materials. Quantitative analysis of the damage events was carried out on a same 3D region inside the reconstructed volumes at different deformation steps for different samples cut from the three kinds of materials. Void number prediction and growth model, based on local stress triaxiality, show a good agreement with the experimental data. © 2012 Springer Science+Business Media B.V.


Roumina R.,University of Tehran | Bruhis M.,McMaster University | Masse J.P.,ArcelorMittal | Masse J.P.,Constellium | And 4 more authors.
Materials Science and Engineering A | Year: 2016

The bending behavior of compositionally-graded martensitic steel was investigated in partially decarburized sheets of alloy 300M. The best combination of strength and bendability was obtained when the thickness of the inner hard core was reduced to one third of the sheet thickness. The improved bending behavior of the compositionally-graded sheet is attributed to (a) the suppression of crack propagation by introducing a more ductile phase at the surface and (b) the spreading of plasticity along the circumferential direction as a result of the presence of a yield stress gradient in the thickness direction. The bendability of the graded material was limited by the initiation and rapid propagation of fracture within the hard core of the sheet. Unlike traditional materials in which the springback angle increases remarkably with increasing yield strength, the compositionally graded material had a small springback angle which is comparable to that of steels having a low yield stress similar to that of the soft decarburized surface layer. © 2015 Elsevier B.V..


Thebault F.,Laboratory Interdisciplinaire Carnot de Bourgogne | Thebault F.,Arcelor Research | Thebault F.,École Nationale Supérieure de Chimie de Paris | Vuillemin B.,Laboratory Interdisciplinaire Carnot de Bourgogne | And 3 more authors.
Electrochimica Acta | Year: 2012

Maturity of numerical simulation represents an important issue in the development of predictive models of galvanic corrosion. As widely used in electrochemical engineering, a coupled electrochemical-transport-reaction (CETR) model is recommended to simulate the current distribution above a galvanic corrosion cell made of the cut-edge of a galvanized steel sheet. Nevertheless, simulating current density distributions obtained experimentally by scanning vibrating electrode technique (SVET) above such a galvanic cell appears to be more accurate using an electrostatic model considering a homogeneous conductivity. In this case, the absence of concentration gradients next to the electrode surface results from convection induced by the microelectrode vibrations. © 2012 Elsevier Ltd.


Bayraktar E.,Paris School of Engineering | Bayraktar E.,French National Conservatory of Arts and Crafts | Ayari F.,Paris School of Engineering | Katundi D.,Paris School of Engineering | And 2 more authors.
Society for Experimental Mechanics - SEM Annual Conference and Exposition on Experimental and Applied Mechanics 2010 | Year: 2010

The general idea of this paper is to produce TiB2 (ceramic particles) reinforced steel matrix composites. These ceramic particles are the best reinforcements for steel matrix composites because of their high thermal stability at higher temperature, high modulus of elasticity, good wetability, low density and their relative stability with steel matrix. This type of new composite family has received much attention as potential structural materials for their high specific strength and stiffness. Therefore, there is a significant interest in developing iron and steel matrix composites and evaluating dynamic behaviours due to their potential usage in automotive industry in future. Final purpose of this paper is to use of the steel sheet for the manufacturing of the lighted structure and manufacturing processes of this sheet. Titanium carbide and titanium diboride TiB2 reinforced steel matrix composites was therefore characterised by optical and scanning electron microscopy. Dynamic behaviours of the base metal and welded specimens have been tested to simulate under the impact-crash test conditions. © 2010 Society for Experimental Mechanics Inc.


Bayraktar E.,Paris School of Engineering | Bayraktar E.,French National Conservatory of Arts and Crafts | Ayari F.,Paris School of Engineering | Katundi D.,Paris School of Engineering | And 2 more authors.
Advanced Materials Research | Year: 2011

This paper reports the production and weldability and toughness evaluation of TiB 2 (ceramic particles) reinforced steel matrix composites. These ceramic particles are optimal reinforcements for steel matrix composites because of their high thermal stability at higher temperatures, high modulus of elasticity, good weldability, low density and relative stability within a steel matrix. This new composite family has received much attention as potential structural materials due to their high specific strength and stiffness. Thus, there is significant interest in developing iron and steel matrix composites and evaluating their dynamic behaviors due to their potential for use in the automotive industry. The goal of the research described in this paper is to study the usage of this new steel family in the manufacture of light structures. Therefore, titanium diboride TiB 2 reinforced steel matrix composites were characterized by optical and scanning electron microscopy. The dynamic behaviours of the base metal and welded specimens were tested under impact crash test conditions. © (2011) Trans Tech Publications, Switzerland.


Roumina R.,University of Tehran | Embury J.D.,McMaster University | Bouaziz O.,Arcelor Research | Zurob H.S.,McMaster University
Materials Science and Engineering A | Year: 2013

In this work, a new approach for processing high strength functionally graded martensitic microstructures with improved fracture properties is presented. The functionally graded martensitic steels are composed of a hard phase at the core and a soft phase at the surface of the structure. The tensile response of the graded steels was analyzed in terms of the extended elasto-plastic transition and a high initial work hardening rate. The behavior of the graded material was modeled using a composite model in which the continuous carbon gradient is replaced with four layers of uniform carbon content. © 2013 Elsevier B.V.


Keller C.,University of Liège | Schwartz R.,University of Liège | Bobadilla M.,Arcelor Research | Tchoufang Tchuindjang J.,University of Liège | And 2 more authors.
AIP Conference Proceedings | Year: 2011

In the Continuous Casting (CC) process, products are sometimes rejected or called defective due to the presence of transversal cracks. This type of macroscopic damage is expected to be due to a ductility loss during cooling in the bending and unbending areas of the CC line. In order to study this damage, a 2D model has been developed to predict at the mesoscopic level the intergranular crack event taking into account the creep and diffusion of voids. Already validated for a microalloyed steel, the model is identified and used in this study to predict the crack formation for three different grades of peritectic steels. Results show encouraging predictions of the damage. These latter, which depend on the chemical composition, are discussed in terms of microstructure and experimental device. © 2011 American Institute of Physics.


Chehab B.,McMaster University | Wang X.,McMaster University | Masse J.-P.,McMaster University | Bouaziz O.,Arcelor Research | And 2 more authors.
Journal of Physics: Conference Series | Year: 2010

Although a number of nanoscale metallic materials exhibit interesting mechanical properties the fabrication paths are often complex and difficult to apply to bulk structural materials. However a number of steels which exhibit combinations of plasticity and phase transitions can be deformed to produce ultra high strength levels in the range 1 to 3 GPa. The resultant high stored energy and complex microstructures allow new nanoscale structures to be produced by combinations of recovery and recrystallisation. The resultant structures exhibit totally new combinations of strength and ductility to be achieved. In specific cases this also enables both the nature of the grain boundary structure and the spatial variation in structure to be controlled. In this presentation both the detailed microstructural features and their relation to the strength, work-hardening capacity and ductility will be discussed for a number of martensitic and austenitic steels. © 2010 IOP Publishing Ltd.

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