Process engineering manager, Zircotube, Paimboeuf,
Research manager, Ecole des Mines de Paris-CEMEF-UMR ENSMP/CNRS 7635, Sophia Antipolis,
Process engineering deputy manager, Zircotube, Paimboeuf,
Pages: 22 Published: Jan 2000
Pilgering is a very complex tube-rolling process in which the metal undergoes a large number of deformation steps. Thus, a good knowledge of the complex strain and stress history is necessary to have better control of tube quality.
We have built a rather simple and fast 3D analytical model to be used directly for process optimization and tool design. It describes the mechanical conditions prevailing during 1he pass as a function of tool design, rolling parameters, and friction. It is based upon a geometrical definition of strains transformed into stresses via the von Mises plastic flow rule and a slab method. This model also includes shear strain computation within a radial-longitudinal tube plane using an upper bound model. Rolling forces are deduced and compared with experiments, and a damage function is computed.
We have also applied the finite element method to pilgering to get more detailed local information on the material behavior under tool contact. It provides us with the possibility of checking the hypotheses of the analytical model.
The results of these models are compared with experimental results and are used to improve quality and productivity in industrial applications.
Zircaloy 4 tubes, cladding tubes, cold pilgering, mechanical modeling, surface defects, damage, finite element method, tool optimization
Paper ID: STP14312S