SIMULATION-MODEL OF COLD PILGERING

Cold pilger rolling is an established technique used for the productio n of precision tubes that are closely related to energy production (nu clear power, off-shore engineering), the fabrication of ball bearings, etc. This process is attractive despite the difficulties in controlli ng the complicated strain path, which latter influences the process pa rameters and the behaviour of the material being pilgered. There are o nly a few models available that can be used in practice for the proper choice of suitable dimensions of the pierced billet for the pilger ro lling of a particular tube and of optimal process parameters. A specia l purpose computer-aided simulation model has been developed for the a nalysis of the influence of different process- and material-parameters on the rolling forces, the deformation, the distribution of accumulat ed strain, the temperatures and the material properties of the pilgere d tubes. Strain increments and the distribution of the accumulated str ain in the material being pilgered are computed with regard to the str ain path and combined with characterization of the material behaviour in terms of plastic anisotropy and cyclic deformation mode. The simula tion model developed, PILGER, is used for investigation of the influen ce of the tube geometry, the rolling geometry, the plastic properties, friction, lubrication and cooling on the roll-separating forces, temp eratures, deformation and properties of the pilgered tubes. The simula tion model is a powerful tool for optimization of the process and cont rol of the final properties of the product.