Cylindrical mandrel drawing of tubes: A matrix method simulation compared with experiment

The demand from industry for metal-forming simulation models has increased during the last ten years. Such models are found to be valuable tools considering process optimization and the development of new processes. The application of simulation models makes it possible to reduce the number of time-consuming experiments. The present work concentrates on the cylindrical mandrel drawing of tubes. If the total reduction is small, i.e., if not more than one drawing pass is necessary, this process is characterized by high productivity: compared to pilger rolling the process has been estimated to be about eight times faster. Tubes which have been manufactured by means of cylindrical mandrel drawing are distinguished by close tolerance and good surface smoothness. The tubes are often delivered in the cold-drawn, strain-hardened condition, i.e., without a subsequent annealing. Because the customer often orders a product of minimum yield stress, it is of great importance to be able to predict the strains of the tube material. The theoretical part of this study comprises the development of a simulation model based on the matrix method, the model being utilized for prediction of strains. In the experimental part a high precision investigation considering one workpiece is presented. This sample was furnished with a square network in the axial plane of symmetry. Strain distributions from theory and experiment are found to be in good agreement.