Duplex stainless steels are often used today in the oil and gas industry because of theirhigh strength and good corrosion resistance. New developments in arctic conditions and athigh pressure require the qualification of these materials at very low temperatures. Thispaper will present the results of an extensive test program dedicated to assessing thelow-temperature behavior of various heavy-wall duplex stainless steel forgings, hotisostatically-pressed (HIP) connectors and hot extruded pipes at temperatures down to –60°C. Several welding processes were also evaluated. The implications for thedesign of duplex stainless steel production facilities will be discussed.

The massive use of air gaps in tooling, per the Evisto® concept, can confine the heatcontributed by the cast alloy in a small volume. The resulting high die wall temperaturesare turned to account to cast parts having ultra-thin walls, of the order of onemillimetre thick. Effective thermal insulation limits thermal exchanges to slow thecooling of a cast alloy. The property that best characterizes this effectiveness is thereciprocal of thermal conductivity, thermal resistance. Air was chosen as the insulatingmaterial because of its many advantages: very favourable thermal conductivity, limitedapplication cost, and zero purchase cost. Evisto®, an innovative tooling design, hasbeen used to produce plates 1 mm thick measuring 130 by 200 mm and automobile seat backs1.2 mm thick measuring 390 by 576 mm. The mechanical properties of the castings soproduced complied with standard EN 1706 of May 2010 for aluminium alloy castings. A patentapplication was filed for the Evisto®concept in August 2010.

An investigation was carried out to quantify and characterize the corrosion behavior ofAZ61A magnesium alloy joints. Extruded 6-mm-thick Mg alloy plates of AZ61A grade werebutt-welded using a solid-state, environmentally cleaner welding process, the frictionstir welding process. The weld specimens underwent immersion, salt spray, pitting andgalvanic corrosion tests in order to quantify and characterize the corrosion rates of thewelds with the influence of different pH values, chloride ion concentrations and thecorrosion time. The corrosion rates, microstructure, scanning electron microscopy andX-ray diffraction analysis concluded the optimum parameters for the usage of the magnesiumalloy welds for the best service applications.

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.

Ecosystem goods and services (EGSs) are of crucial importance for the economic and socialdevelopment of human communities. The well-established life cycle assessment (LCA) methodis facing a number of challenging improvements to define new Characterization factors(CFs) for life cycle impact assessment (LCIA) of EGSs. Very recently, extensive workconducted under the UNEP/SETAC Life Cycle initiative has been completed with the goal ofproviding new LCIA methods and spatially differentiated mid-point CFs for land use andland use change impacts on biodiversity and ecosystem services. However, the implementedmodels do not enable one to assess the actual damage to ecosystem functionality, and thusthe relationship among EGSs and related areas of protection (e.g. AoP of “NaturalResources”) remains undefined. This paper aims at investigating the potentialcharacterization ability of the Emergy method for LCIA of EGSs. The goal is to use theextensive libraries of Unit Emergy Values (UEVs) of primary services and resources as CFsfor LCIA to evaluate the physical contribution of EGSs in supporting life cycle processes.Having its roots in thermodynamics and systems ecology, Emergy can appraise a larger andmore diversified (than LCA) number of EGSs through a common physical denominator, i.e. thesolar emjoule or seJ, which measures the solar energy embodied in natural products. Emergythus has a typical Nature-oriented perspective, accounting for the available energy thatis used up by the natural cycles, directly and indirectly, to generate biotic and abioticresources. A library of selected UEVs (more than 100) for biophysical EGS valuation hasbeen framed including values collected from the Emergy literature and formulated on thelatest planetary baseline (i.e. 15.2E + 24 seJ/yr). Advantages and limitations for futureapplication of these values toward an LCIA mid-point impact characterization of Emergy arediscussed. UEVs may represent mid-point LCIA factors for ecological contribution analysis,enabling one to account for the memory of energy previously required to produce EGSs,which can be used as a proxy to assess the future environmental work necessary toregenerate the used EGSs. However, the added value of Emergy for LCA is still debated,mainly because of the low accuracy and unclear meaning of the UEVs in relation to theavailability of resources. Therefore, Emergy can be conceived as a suitable physicalmeasure complementary to the economic valuations and current “user-side” tools applied inLCA.

Cet article présente les derniers travaux réalisés par Dassault Aviation dans le domainedes charges et des vibrations aéroacoustiques, liées à la pression engendrée parl’ouverture, en vol, d’une soute à armement. En effet, dans le cadre du programme de dronenEUROn, Dassault Aviation établit les charges aéroacoustiques s’exerçant sur la structurede la soute à armement et analyse ainsi leur effet en termes de fatigue acoustique et devibrations d’équipements. Etant données la bande de fréquences étudiée et la complexitédes charges aéroacoustiques, de nouvelles méthodologies et de nouveaux outils ont étédéveloppés pour prédire le comportement dynamique de la structure, dans le domaine desbasses et moyennes fréquences. Ces méthodes, leur application novatrice chez DassaultAviation pour ce qui concerne la prédiction de l’environnement vibratoire dans le cadre dunEUROn, ainsi que les tendances d’améliorations ultérieures issues de cette application,font l’objet de cet article.

Refractory castables containing alumina-magnesia/self-forming spinel(MgAl2O4) are used in impact pads of steel ladles in steelmakingprocesses. In order to understand the wear mechanisms of refractory materials, severalrecipes were tested from a corrosion, slag resistance and thermal shock point of view. Theresults show that the corrosion is extremely limited at the slag/refractory interface forall cases. Nevertheless, for higher cement alumina content castables, the formation ofcracks is observed in refractory castables into which slag can penetrate. The slag reactswith the alumina to form a new phase such as hibonite (CA6) and calcium dialuminate (CA2).The volumetric change of these reactions involving CA2 and CA6 lead to the apparition ofmacro-cracks. Thus, the penetration of slag and steel are increased, causing hotmechanical properties to degrade. For lower cement alumina castables, the formation ofmicro-cracks is avoided by controlling volume expansion. Thus, the slag deposit reactswith alumina grains and the matrix at the slag/refractory interface to produce amonomineral layer of hibonite. In this way, the monomineral layer acts as a barrier andlimits the penetration of slag and steel into the refractory lining. Thus, to increase thelifetime of refractory castables containing alumina-magnesia/self-forming spinel, it isadvised to control volume expansion in order to avoid the formation of cracks and limitthe penetration of secondary metallurgy steel ladle slag.

Deposition of Ni3P nano-scale layer on B4C nanoparticles in fourcontents of sodium hypophosphite as reducing agent including 5, 10, 15 and 30 g/l viaelectroless coating were done to investigate the effect of reducing agent content on thecoating thickness of deposited Ni3P. The bath pH and temperature was 5.5 and 85°C, respectively and the coating time was 25 min. The powders were characterized bytransmission electron microscopy (TEM) and the phases present were revealed by X-raydiffraction (XRD). Nickel and phosphorous contents of the coatings were measured byinductively coupled plasma analysis (ICP). The results revealed that by increasing thereducing agent content from 5 g/l to 30 g/l the average coating thickness increased from19 nm to 28 nm. Although the increasing effect of adding sodium hypophosphite content waspreserved, there is a critical amount for sodium hypophosphite content to increase thecoating thickness.

A laser-welded blank (LWB) offers several notable benefits including decreased part weight, reduced manufacturing costs, increased environmental friendliness and improved dimensional consistency. However, in order to take advantage of these benefits, designers need to overcome the formability of LWBs and be able to accurately predict the LWB forming characteristics early in the design process. We present a new approach to predict the maximum elongation of the laser seam; for example, for Advanced High-Strength Steel (AHSS)-based LWBs. This approach is based on a coupling model taking into account the thermal, metallurgical and mechanical phenomena. A comparison of numerical and experimental results shows very good agreement. These approaches offer a considerable advantage in obtaining the formability limits for all configurations.

What environmental constraints will materials have to face in the future? Can currentmeasurement tools like LCA (Life Cycle Analysis) support the choices of material and adaptto these constraints to pave the way to a sustainable world? Are there some alternative orcomplementary approaches to enhance the quality of information for decision makers? Theaim of this article is to provide answers to these three questions. The society oftomorrow, in the second half of the 21st century, will be a society where the circulareconomy will play a more important role and thus will help reduce materials waste. This isa critical aspect of sustainability. To get there, the decisions have to be enlightenedand fair, because the decisions (or non-decisions) made today shape the world that futuregenerations will have to manage. Furthermore, Lord Kelvin used to say: “what you can’tmeasure, you can’t improve”. Therefore, these decisions have to be supported bymeasurement tools that will properly capture the stakes of reuse and recycling at the endof life of products. Today, LCA is the common tool used to address this matter. However,the present article has shown that LCA cannot incorporate the whole complexity ofsustainability. LCA is good at considering micro-scale issues, comparing one solution withanother, in a static approach. How can it give right directions to decision makers inorder to support the vision of a circular economy? The application of different standardsshowed that it is not easy at all and that recycling product at their end of life are notrewarded equally and sometimes not promoted at all. Therefore rebound effects leading tocontradictory decisions may occur. LCA alone is not enough to make enlightened decisions.It should be complemented by other methods. This was proposed in the last part. Based onthe IPAT equation, this approach tries to capture different aspects that are not addressedproperly by LCA, due to the fact that the functional unit is too restrictive, that thetime dimension and prospective approach should be more integrated, and that it shouldenlarge the scale of the analysis to the macro-economy and the socio-economy. It shouldalso recognize that the efforts have to be shared by different players including materialindustry and manufacturers, policy makers and society in general. As a general conclusion,we are convinced that tomorrow’s society will recognize the value of materials that arerecyclable and reusable, like steel has been for many decades. But there is still a clearneed to addressing, in research and development, the improvement of the metrics, combiningsocial, environmental and economic assessment, so that the sustainability value ofmaterials is properly measured. These are the objectives of the Sovamat Initiative and theSAM conferences.

To optimize the process and improve the degree of reduction, a two-stage experiment wasdesigned. It was carried out in a micro-fluidized bed. It is operated as a differentialreactor to ensure every particle in the micro-fluidized bed is at equal temperature,concentration and residence time. The experiment used iron ore powder from Yangdi. Thereducing gas and temperature in the pre-reduction stage were, respectively, pure CO and625 °C. In the final reduction stage, the temperature and reducing gas were, respectively,800 °C and pure CO. The residence time was between 10 min and 60 min. In addition to theexperiment, a microscopic technique was also carried out. The test shows a significantinfluence of the temperature and residence time of the two-step experiment on the finalreduction degree.

Le but de ce travail est une contribution à l’étude de l’efficacité d’utilisation dutraitement de phosphatation au zinc pour la lutte contre la corrosion des armatures dansle béton. Pour réaliser cette conversion chimique superficielle, des échantillons en acierrond à béton ont subi une phosphatation cristalline dans un bain de phosphate de zincmodifié par des ions Ni2+. Par suite, nous avons évalué leur comportement à lacorrosion dans une solution simulée du béton au moyen de différentes techniquesélectrochimiques. Les résultats obtenus montrent que le traitement de phosphatation permetd’améliorer d’une manière significative la résistance à la corrosion de l’acier. En effet,les échantillons phosphatés, par rapport à ceux non phosphatés, présentent des valeurs depotentiel de corrosion et de piqûration plus nobles ainsi que des densités de courant decorrosion plus faibles. Les mesures d’impédances confirment cette tendance, les spectresobtenus montrent une nette augmentation de la résistance de transfert de chargesconjointement à une diminution de la capacité de la double couche électrochimique deséchantillons traités. Cette action protectrice est due au fait que la couche de phosphateobtenue joue le rôle de barrière physique face à la diffusion des ions chlorures d’unepart, sa dissolution en surface dans la solution simulée fortement alcaline libère lesions PO43- rentrant dans la réaction de formation d’un film depassivation jouant le rôle de barrière chimique face à l’amorçage de la corrosion parpiqûres, d’autre part.

The finite difference method of the low-alloy wear-resistant steel quenching process wasstudied. The temperature field and cooling rate variation of thickness of 45-mmwear-resistant steel (NM450) were calculated for different quenching practices. Themicrostructure and hardness of quenched plates were examined. The results indicate thatwhen quenching started, the cooling rate was highest on the subsurface and decreasedgradually until the center of the plate. However, as the quenching progressed, the coolingrate distribution along the plate thickness was reversed. The cooling rate increasedlinearly when the heat transfer coefficient (HTC) increased from 0–10 000W/m2 K, and then the speed gradually slowed down until achieving the maximumcooling rate. Close to the plate mid-thickness, the maximum cooling rate was easilyreached. Compared with high-pressure (HP) quenching and low-pressure (LP) quenching, underthe HP + LP continuous quenching mode, it is possible to obtain a high critical coolingrate in the temperature range of 900 °C–400 °C and small temperature difference betweenthe surface and center below 400 °C. The microstructure and hardness distribution on theplate surface for the HP + LP quenching mode indicated 100% martensite on the surface andmartensite with a little granular bainite in the plate center, while the hardnessdifference in the entire steel plate was less than 7%. This study provided guidance forthe formulation and optimization of wear-resistant steel.

The aim of this work is to produce metallic coatings onto a steel substrate type E335 in order to hardening and improving the tribological properties of contact surfaces. In this study, two different coatings of stainless steel 18/8 and molybdenum realized with and without bond coat in Ni-Al were sprayed using a thermal flame spray technique. The microstructures of the two deposits are obtained using an optical microscope (OM), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Measures microhardness under a load of 200 g, are performed on the polished surfaces of these two types of deposits. The wear and the determination of the coefficients of friction of the two deposits tests were performed in dry conditions. A pin on disc configuration on a tribometer type TE 91 was used with different normal loads and a sliding speed of 0.5 m/s. The results showed that the microstructures obtained by OM and SEM of stainless steel present a dense and compact microstructure. It contains a low porosity and unmelted particles in comparison with the coatings of Mo. In addition, it was found that the spray-coated stainless steel 18/8 exhibited higher microhardness, higher wear resistance and significantly low friction coefficient in comparison with those of Mo coatings.

Online detection and monitoring of phase transformation using non-destructiveelectromagnetic system in industrial hot strip mill processing of steels are reported. Thesystem renders wide range of possibilities for advanced control and fine tuning of the hotrolling and run-out table cooling parameters. These in turn allow for processmodifications to better control the microstructure of hot rolled bands. In particular,such modifications can attenuate the adverse effects of uncontrollable cooling of hot bandcoils that leads to severely non-homogeneous hot band microstructure. An example ofapplication is given demonstrating how reducing the non-homogeneity of hot bandmicrostructure with the aid of online hot strip mill electromagnetic system can helpeliminating the off-thickness defects in advanced high strength steel full hard stripsthus contributing to lowering the production costs and increasing the yield.

The European Waste Framework Directive (2008/98/EC) explicitly specifies the hierarchyfor waste management: prevention, preparation for re-use, recycling, other recoveryactions, disposal. When selecting waste management options, this waste hierarchy should befollowed. A deviation can only be justified by Life Cycle Thinking (LCT) on the overallimpacts. The application of this principle in the Flemish waste management practicetriggered the need for evaluation of treatment options for several waste streams.Alternative treatments were evaluated for waste batteries, used frying oils and waste oil.The evaluation methodology combined life cycle assessment with technical and economicalviability criteria. These cases show that LCT does not allow to establish a “generalpriority order”. In each case reasons for deviation from the standard waste hierarchycould be given, but also none of the evaluated options can be considered as the best. Theevaluation showed that the priority is largely dependent on location-specificcharacteristics of inputs, outputs, processes and installations and that the establishmentof local and global environmental priorities always implies a value choice. In thispresentation, we will present the results of the three cases and provide a methodologicalframework for life cycle thinking in waste management policy.

At the end of 2008 and in response to the economic crisis, the EU launched a Recovery Plan supported by technology initiatives, one of them being the European Green Car Initiative (EGCI) to help the car industry design next-generation passenger vehicles, which address fuel efficiency and carbon footprint issues at the level of the challenges of the 21st century. The European steel sector, which supplies material to the European car industry, which builds 1/3 of all passenger cars in the world, has launched an extensive, bold and imaginative series of projects to address lightweight design, cost, safety, sustainability, availability, recycling, electric applications and Life Cycle Assessment (LCA), which are the main technical topics, as steel retains an essential role in the design of these future green vehicles. Highlights of these are presented here, such as the development of new steel grades, either new advanced high-strength steels or low-loss steels for electric cores, the co-design of steel solutions with OEMs and the importance of LCA in vehicle conception.

les différentes méthodes qui utilisent l’essai d’indentation pour estimer la ténacité sont revues et commentées. Pour les matériaux fragiles, les formules sont principalement basées sur la mesure des fissures formées par l’indenteur ou, si l’essai est instrumenté, sur les décrochements (pop-in) observés sur la courbe charge-déplacement. D’autres méthodes moins connues peuvent utiliser la mesure de l’ouverture en fond de fissure, une équivalence entre la longueur de fissure formée et l’accroissement de pénétration de l’indenteur ou le clivage provoqué par une indentation proche du bord du matériau étudié. Pour les matériaux ductiles aucune fissure n’est visible à la surface, même pour les fortes charges appliquées. Dans ce cas la ténacité est reliée par la mécanique continue du dommage à un dommage critique mis en évidence par la diminution du module d’élasticité avec l’augmentation de la profondeur d’indentation. Toutes ces méthodes permettent de calculer la ténacité avec une incertitude pouvant aller au maximum à 50 %.