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.

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.

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.

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.

A model has been developed to describe the rheology of austenite at high temperatures, characteristic from hot strip rolling of low-alloyed steels. It is based on the evolution of a single dislocation density through storage and strain rate-dependent dynamic recovery. The model gives good predictions of the stress-strain curves in a wide range of temperatures, strain rates and chemical compositions. It is now applied on industrial hot strip mills to predict the rolling loads of a wide range of industrial steels.