Transient Mode Study During the Material Pressure Treatment of the Wave and Auto-oscillatory Processes

Analysis of product quality after metal processing by pressure often showed that one cannot obtain high quality surface using cold rolling, running, dragging and other similar processes. It is related to the tool-billet interaction optimization without considering variable friction along with transient wave and auto-oscillatory processes. To substantiate the role of longitudinal and transverse wave processes, a simulation model has been developed, which models the billet surface layers as a beam on elastic base loaded by abruptly applied tangential forces that frequently exceed their critical values. Using mathematical models, we investigated the billet dynamical instability conditions, in which the surface layer integrity failed under stresses and strains exceeding their critical values. The results obtained allows one to determine hazardous states of the billet surface layers when an abrupt load is applied during the initial moments of the billet capture and also at the end of the tool-billet slipping during their motion velocities equalization.