22. Precision of the Tubes Produced by Drawing and Cold Rolling

This paper presents the drawbacks of tube cold deformation classical processes such as drawing through stationary dies and cold rolling by rolls and rollers. Large assortments of cold-deformed tubes are produced by these methods. In order to increase their quality, several improvements of cold deformation methods have been suggested. At the first stage, finite-element models for tubes produced by cold drawing and rolling were developed, and regression models were prepared for the dependence between the tube wall thickness variation and the process variables. Based on that, a new formula was developed for optimal grooving parameters. It allowed reducing the loading and longitudinal thickness variation of produced tubes. Finally, in order to correct the thickness variation for conventional methods, the preliminary grading on the profiled mandrels was proposed.