SEDL / STP / STP1245-EB / STP15193S

Modeling of Damage in Cold Pilgering

Aubin, JL
Docteur ingénieur, adjoint au service production, Zircotube, Paimboeuf,

Girard, E
Agrégé génie mécanique, I. U. T. de Saint-Nazaire, L. A. M. M., Saint-Nazaire,

Montmitonnet, P
Chargé de Recherche, Ecole des Mines de Paris-CEMEF-UA CNRS 1374, Sophia-Antipolis,

Pages: 19    Published: Jan 1994

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Abstract

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.