References of "Lecomte-Beckers, Jacqueline"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailCorrosion behaviour of different hot rolled steels
Perez, F. J.; Martinez, L.; Hierro, M. P. et al

in Corrosion Science (2006), 48(2), 472-480

The oxidation-corrosion behaviour of hot rolled alloys was examined by electrochemical impedance spectroscopy. The corrosion behaviour of the non-oxidised alloys was first determined in order to have a ... [more ▼]

The oxidation-corrosion behaviour of hot rolled alloys was examined by electrochemical impedance spectroscopy. The corrosion behaviour of the non-oxidised alloys was first determined in order to have a reference behaviour. Then, each alloy was oxidised for 1 and 3 days at 650 degrees C in air and its corrosion behaviour was also determined. For all the alloys, Fe2O3 was formed at the scale-gas interface. However, the Fe2O3 crystallographic structures varied as a function of the alloy composition. Differences in the corrosion behaviour are due to the thickness, the microstructure and the porosity of the scale. The new graphite chromium iron alloy (Hi-Cr + C) have an oxidation-corrosion behaviour close to the indefinite chill double paired (ICDP) one and is therefore thought to be a good candidate to replace the ICPD alloy. In the case of the high speed steel (HSS) alloy, the oxidation-corrosion kinetics are too slow to prevent sticking problems. The Co addition decreases the corrosion-oxidation rates for the non-oxidised and oxidised samples but this effect is limited in time. (C) 2005 Elsevier Ltd. All rights reserved. [less ▲]

Detailed reference viewed: 38 (1 ULg)
Full Text
Peer Reviewed
See detailThixoforging of 7075 aluminium alloys at high solid fraction
Vaneetveld, Grégory ULg; Rassili, Ahmed ULg; Lecomte-Beckers, Jacqueline ULg et al

in Solid State Phenomena (2006), 116-117

Thixoforging is a type of semi-solid metal processing at high solid fraction (0.5 < f(s) < 1), which involves the processing of alloys in the semi-solid state. 7075 alloy has been used as a feedstock for ... [more ▼]

Thixoforging is a type of semi-solid metal processing at high solid fraction (0.5 < f(s) < 1), which involves the processing of alloys in the semi-solid state. 7075 alloy has been used as a feedstock for thixoforming in order to investigate thixoformability of a high performance aluminium alloy at high solid fraction. The microstructure in semi-solid state consists of fine spheroidal solid grains surrounded by liquid. Thixo behaviour allows laminar flow that avoids macro-porosity and other casting defects and gives better mechanical properties; so we can reduce the weight of functional parts. Higher solid fraction of 7075 alloy is less sensitive to temperature, avoids metal splash at high speed, allows laminar flow at high speed and gives a good smooth surface without stick-slip phenomenon. The process is quicker with less energy and so the production rate increases and the tool has longer life. However, high solid fraction promotes freezing flow because of faster solidification and the lack of liquid phase. This freezing flow creates solid/liquid segregation and increases the forming force. [less ▲]

Detailed reference viewed: 76 (8 ULg)
Full Text
Peer Reviewed
See detailInfluence of excessive carbides upon strength of hot rolled rolls of steel similar to high speed grade
Lecomte-Beckers, Jacqueline ULg; Herman, M.; Breyer, J. P.

in Stal' (2006), 9

This paper will illustrate the choice of the alloying elements and their content in the current grade. By using sophisticated laboratory examination techniques such as differential thermal analysis ... [more ▼]

This paper will illustrate the choice of the alloying elements and their content in the current grade. By using sophisticated laboratory examination techniques such as differential thermal analysis, scanning electron microscopy and image analysis, the metallurgical parameters of Aurora grade will be described and compared to those of the Kosmos grade. An attempt will also be made to connect all our laboratory results to the good behaviour of the alloy in operation in the early stands of Hot Strip Mills. [less ▲]

Detailed reference viewed: 34 (8 ULg)
Full Text
Peer Reviewed
See detailDetermination of solidification parameters used for the prediction of the thixoformability of several steel alloys
Lecomte-Beckers, Jacqueline ULg; Rassili, Ahmed ULg; Robelet, Marc et al

in Solid State Phenomena (2006), 116-117

This paper focuses on the liquid fraction curves of several steels and the correlation between liquid fraction, temperature and heating rate. The work has been performed along two main axes. First, the ... [more ▼]

This paper focuses on the liquid fraction curves of several steels and the correlation between liquid fraction, temperature and heating rate. The work has been performed along two main axes. First, the solid fraction versus temperature has been obtained experimentally by differential scanning calorimetry (DSC), limited to low heating rates. Then, a shift of the liquid fraction curves has been noticed at high industrial heating rates. The quantification of this effect could not be carried out by DSC and required the elaboration of another experimental device. [less ▲]

Detailed reference viewed: 27 (11 ULg)
Full Text
Peer Reviewed
See detailInfluence of experimental parameters on properties and microstructure of the steel X210CrW12 in the semi-solid state
Fraipont, Céline; Puettgen, Wolfgang; Bleck, Wolfgang et al

in Solid State Phenomena (2006), 116-117

This paper deals with the examination of the steel grade X210CrW12 and its suitability for Thixoforming. In the semi-solid state, the microstructure of this steel consists of a homogeneous distribution of ... [more ▼]

This paper deals with the examination of the steel grade X210CrW12 and its suitability for Thixoforming. In the semi-solid state, the microstructure of this steel consists of a homogeneous distribution of globular particles surrounded by liquid. Additionally, carbides are stabile up to fraction liquid contents of approximately 40%. After quenching, this steel reveals a globular austenitic microstructure with eutectic (former liquid phase) at the grain boundaries. Compression tests permit to determine the influence of different process parameters on the properties and the material behaviour in the semi-solid state. Their influence on the microstructure was investigated but not yet highlighted. Further investigations on this steel allow a fine-tuning to establish optimal process windows of the different thixoforming- and rheoforming-routes. [less ▲]

Detailed reference viewed: 28 (2 ULg)
Full Text
Peer Reviewed
See detailCharacterization of Duplex steel Uranus 76N during deformation and heat treatment
Lecomte-Beckers, Jacqueline ULg; Moureaux, P.; Carton, Marc ULg et al

in Physica Status Solidi A. Applications and Materials Science (2006), 203(15), 3651-3664

Duplex Uranus 76N is characterized by metallography, thermal and mechanical analysis. The investigation shows that the microstructure of such a Duplex strongly depends on the cooling conditions ... [more ▼]

Duplex Uranus 76N is characterized by metallography, thermal and mechanical analysis. The investigation shows that the microstructure of such a Duplex strongly depends on the cooling conditions determining the quantity of austenite formed in the ferrite matrix. Numerical simulations of 76N behavior during the rolling process and service life require the knowledge of the recrystallization state during rolling steps at high temperature, thermal parameters such as dilatation, density, specific heat, thermal diffusivity, thermal conductivity and mechanical constitutive laws. These material parameters are determined and presented in this study. [less ▲]

Detailed reference viewed: 70 (4 ULg)
Full Text
Peer Reviewed
See detailEffect of boundary conditions and heat source distribution on temperature distribution in friction stir welding
Simar, A.; Lecomte-Beckers, Jacqueline ULg; Pardoen, T. et al

in Science & Technology of Welding & Joining (2006), 11(2), 170-177

on Al-6005A have been carried out using a fully instrumented milling machine. The power input was calculated from the measured torque and forces. The thermal cycles were measured at various locations ... [more ▼]

on Al-6005A have been carried out using a fully instrumented milling machine. The power input was calculated from the measured torque and forces. The thermal cycles were measured at various locations close to the weld centreline. A finite element pseudothermal model was developed, taking into account the influence of the welding parameters on the power input. The distribution of the total power input between surface and volume heat sources was also studied. The measured and predicted thermal cycles are in good agreement when proper contact conditions between the workpiece and the backing plate are introduced. [less ▲]

Detailed reference viewed: 60 (1 ULg)
Full Text
Peer Reviewed
See detailInfluence of carbide precipitation on hot hardness of high speed steel rolls
Herman, M.; Breyer, J. P.; Lecomte-Beckers, Jacqueline ULg

in Proceedings of the Southern African Roll Users' Conference (SARUC) (2006)

This paper will illustrate the choice of the alloying elements and their content in the current grade. By using sophisticated laboratory examination techniques such as differential thermal analysis ... [more ▼]

This paper will illustrate the choice of the alloying elements and their content in the current grade. By using sophisticated laboratory examination techniques such as differential thermal analysis, scanning electron microscopy and image analysis, the metallurgical parameters of Aurora grade will be described and compared to those of the Kosmos grade. An attempt will also be made to connect all our laboratory results to the good behaviour of the alloy in operation in the early stands of Hot Strip Mills. [less ▲]

Detailed reference viewed: 70 (7 ULg)
See detailMaterials for advanced power engineering 2006 : Proceedings of the 8th Liège conference
Lecomte-Beckers, Jacqueline ULg; Carton, Marc ULg; Schubert, F. et al

Book published by Schriften des Forschungszentrum Julich, Reihe energietechnik/Energy Technology Forschungszentrum Julich (2006)

Detailed reference viewed: 84 (1 ULg)
See detailthermal conductivity and microstructure
Lecomte-Beckers, Jacqueline ULg

Scientific conference (2005, May)

Detailed reference viewed: 5 (1 ULg)
Full Text
See detailFinit element modelling of an asynchronous motor with one broken rotor bar, comparison with the data recorded on a prototype and material aspects
Guérard, Suzanne ULg; Gyselinck, Johan; Lecomte-Beckers, Jacqueline ULg

in Bulletin Scientifique de l'AIM (Association des Ingénieurs Electriciens sortis de l'Institut Electrotechnique Montefiore) (2005), 1

This work studies the problem of broken rotor bars in cage induction motors. To this aim, an induction machine from WEG Motors was modelled by means of the finite element method. The motor modelled is a ... [more ▼]

This work studies the problem of broken rotor bars in cage induction motors. To this aim, an induction machine from WEG Motors was modelled by means of the finite element method. The motor modelled is a 18.5 kW four-pole induction motor with a straight rotor cage. The field distribution and stator phase currents were computed for a motor without broken rotor bars and for a motor with one broken rotor bar. The computed stator phase currents were compared to the ones recorded on motors respectively no broken rotor bar and with one broken rotor bar. The FE model and an equivalent scheme of the motor permitted to show that the resistance of the rotor cage was higher than expected, considering only the temperature effect on the conductivity of the rotor bars. A metallurgic analysis of the aluminium alloy of two rotor bars revealed the presence of a very high density of silicon and silicon oxide inclusions, as well as the presence of shrinkages and cracks, which have a negative impact on both conductivity and mechanical strength. A corrected value of the rotor bar conductivity was used in the finite element model and led to a good agreement with the experimental results. The field perturbation associated with a broken rotor bar produces a concentration of flux near the bar ahead of the broken one, considering the counterclockwise direction of rotation of the rotor. This flux concentration results in higher current values and hence in higher stresses in the bar ahead of the broken one. [less ▲]

Detailed reference viewed: 83 (6 ULg)