Contribution à l’amélioration de la rectitude dans l’obtention de produits longs : application aux abouts de rails

Abstract : Long workpieces are characterized by one dimension, usually length is larger than the height and width, for example, railway rails. These products are obtained by hot rolling and then cooling. During manufacturing process, heterogeneity of cooling and plastic deformation induced straightness error. In order to correct this geometrical error, cold straightening process is necessary. Usually, straightening machines are used to correct the straightness of the workpiece center however; the ends' sides were still not straightened. Based on the optical measurement profile, these ends are straightened by mechanical press. The measuring/straightening closed loop is repeated until the straightness of the product is conformed. The process time depends on the knowledge of key parameters related to geometry and material of workpiece. The objective of this research work is to optimize straightening process of the ends of long workpieces. As a first step, the elastic deformation generated during the measurement of long workpiece has been filtered. Then, a coupled analysis of measurement was used to separate error of machine measurement from workpiece measurement, which allowed a better assessment of workpiece straightness profile. Furthermore, based on straightness profile, a semi-automatic straightening methodology has been developed. It is essentially based on an interaction between metrology and mechanics and it is a contribution to the automation of straightening process for ends parts of long workpieces.
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Abdelwahed Belhadj Ahmed. Contribution à l’amélioration de la rectitude dans l’obtention de produits longs : application aux abouts de rails. Autre. Ecole nationale supérieure d'arts et métiers - ENSAM, 2013. Français. ⟨NNT : 2013ENAM0066⟩. ⟨pastel-00973531⟩

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