Docteur ingénieur, adjoint au service production, Zircotube, Paimboeuf,
Agrégé génie mécanique, I. U. T. de Saint-Nazaire, L. A. M. M., Saint-Nazaire,
Chargé de Recherche, Ecole des Mines de Paris-CEMEF-UA CNRS 1374, Sophia-Antipolis,
Pages: 19 Published: Jan 1994
Surface defects may occur in cold pilgering of Zircaloy-4 tubes caused by the stress and strain history. Because the low frequency of these defects makes their direct study difficult, a model has been built to describe the mechanical conditions that prevail during the pass, as a function of tool design, rolling parameters, and friction. It is based upon the geometrical definition of strains that is transformed into stresses via the Von Mises plastic flow rule and a slab method. Rolling forces are deduced and compared with experiments, and the damage function is computed. A number of experimental observations has been performed (axial movements of tube and mandrel, bulge wave propagation, contact length, shearing strains, etc.) that provides the correct hypotheses for the model. A correlation is established between the computed damage function and the frequency and severity of the studied defects.
zirconium, zirconium alloys, nuclear materials, nuclear applications, radiation effects, cladding tubes, cold pilgering, mechanical modeling, surface defects, damage (materials)
Paper ID: STP15193S