HEF Groupe (France)

Two types of wear-resistant, heavy-duty rolls are widely used in high carbon steel strips cold rolling: High Speed Steel (HSS) rolls and chromium-electroplated rolls. Lower costs and replacement of chromium, criticized because of its effects on health, are two reasons to look for another coating solution for rolling mill rolls. To be economically viable, it must maintain surface quality in accordance with customer requirements, and / or allow larger strip reduction per pass, and / or work at higher rolling speed and / or resist wear better so as to roll more coils between roll changes. Different phenomena, strongly related to the nature of roll surface, must be controlled in order to bene t from such improvements: severe adhesive wear of strip and adhesive transfer ("pick up", "roll coating"), abrasive wear of rolls. DLC coatings are widely used in various tribological applications. Their resistance to wear and adhesion gives them a high potential in rolling. The interest of a hydrogenated DLC coating (here, with 20 at.% H) has therefore been studied for this application. The proposed paper analyzes its tribological and mechanical characteristics under conditions relevant to rolling processes, using two well adapted tests. Its resistance to transfer, severe adhesive wear, abrasive wear and fatigue is evaluated and compared with reference materials used in the rolling industry, uncoated and chrome-coated HSS, but also with other PVD coatings (TiN, CrN, TiBN) already described in previous papers. The results show the good potential of this coating in this application.

Nous allons maintenant etudier une entreprise americaine emblematique d’une tendance forte des entreprises de l’economie numerique: Salesforce.com. Cette entreprise californienne s’est resolument orientee des son origine (1999) vers le «Software as a Service» (SaaS). Cette entreprise pionniere a propose dans le domaine des logiciels de management de la relation client de fournir a ses clients un service et non un logiciel. Apres une presentation de la societe et de son environnement, nous allons etudier, comme nous l’avons fait pour REXEL, la place de la coproduction de valeur dans sa strategie.

Moulding technology facilitates the production of components with complex designs. In France the turnover of the moulding industry doubles each ten years and the main sector of activity of this industry is polymer moulding, which accounts for 58 % of the total turnover. Because of fast tool wear caused by the severe conditions experienced during injection processes increased tool performance is needed. Methodical investigations show tool life limitations. Complementary industrial points of view indicate that tool life is often limited by surface wear phenomena (see annexes I and 2). Abrasion, corrosion and sticking phenomena can cause tool surface damage whilst mechanical stresses can induce fatigue and plastic deformations, Tool performance must be adapted to different solicitations on it's core volume and surface. Surface engineering sciences, numeric simulations and surface analyses are necessary to establish correct diagnostics which will allow for developments enabling a significant increase in tool life. Core material improvement and better surfaces treatments are also needed. New designs and new metallurgical choices could be industrialised to produce short series or prototypes. Surface phenomena should also be examined using a microscopic approach. A surface may be seen as the limit between solid and gas (see annexe 3). With careful observation of the surface from the outer limit to the inner undamaged metal structure one can identify several layers such as adsorption layers, oxide layers and brittle metal layers. An oxide layer whose growth rate and stability are dependent on thermodynamic conditions covers most metallic surfaces. Topographic analysis is a complementary approach to understanding surface phenomena such as sticking or seizure. Reflectivity and colour measurements can provide very efficient though indirect quantification of surface morphology and roughness (see annexe 4). Tribological tests confirm the relation between the coefficient of friction a surface and it's reflectivity. Numeric simulations can make tool design optimisation easier. New composite materials covered with metallic layers can be used to make moulds for the production of prototypes. The HIP (Hot Isostatic Pressure) technology is competitive for the production of moulds with complex designs. Aluminium moulds covered by protective layers are attractive for medium series. Specific developments of PVD processes are necessary to keep good adhesion at low temperature (150 °C). Recent progress in steel metallurgy offers improvements on machining, welding and mechanical resistance. Powder metallurgy, laser and plasma technologies are efficient means for restoring tools. Super alloys can solve glass moulding problems. In the case where several types of solicitations are present, coating properties complement core material properties. Thermal treatments and thermo-chemical treatments can improve resistance to thermal and mechanical fatigue. Thick metallic layers can offer efficient protection against corrosion. PVD coatings produce a large quantity of materials, which can offer good resistance to abrasion and oxidation or offer a low friction coefficient (see annexe 5). Multilayers can combine several of these properties. Specific surface finishing and recent process progress allow this technology to be carried out successfully. Multi-technological coatings are industrially used in the case of severe corrosion + abrasion or fatigue + abrasion.

Addresses the vexed question of how to discuss an object, e.g. the company, without adopting an a priori epistemological position. Attempts to tackle the problem of how representations, which form an integral part of all epistemology, arise. The first level of representation, where content is imparted to a concept designating an object, is the model understood in its traditional sense, as a reduction and simplification of reality. Raises the problem of the existence of content, and in doing so calls forth images and metaphors: the former as a mediating force and the latter as the creative element of the discourse induced by an image. Enquires into the inter‐relationship between model, image and metaphor – a task that can only be performed by examining the role played by ideology in their emergence.

ABSTRACT “Culture,” which is taking on increasing importance in contemporary foreign language pedagogy, has also been the subject of much debate. Definitions of what culture is have proliferated, from Matthew Arnold to Levi‐Strauss to Edward Hall, and not infrequently lines of opposition have formed around them. But if we abandon an oppositional mode of thinking and address the question of culture and language learning from the perspective of the affective elements contained within both, we may be able to adopt a more ecumenical approach to the former and provide ourselves with a much more powerful tool for helping students acquire the latter.