Simulation and mechanical analysis of the cross-wedge rolling process
The effect of process parameters including forming angle, stretching angle, area reduction and friction coefficient on the cross-wedge rolling (CWR) of AISI 1045 steel and Ti6Al4V alloy workpiece was investigated numerically using thermo-mechanical model analysis. The numerical simulations were further validated experimentally. The thermo-mechanical analysis showed the general trends of the variations of the temperature, effective strain and stress, maximum principal stress, mean stress, stress triaxiality and strain rate of the workpiece during high and low temperature CWR process. The temperature distribution in the workpiece was shown to be non-uniform during CWR process. When the initial temperature of the workpiece was relatively low, the workpiece temperature increased, a heating effect of the plastic deformation, while higher initial temperatures caused the cooling of the workpiece. The most significant process parameters on the deformation of the workpiece in CWR were shown, for the studied range of parameters, to be the area reduction and stretching angle. Both were found to increase the tool forces. The friction coefficient between tool and workpiece was found not to affect the workpiece deformation significantly after a value of 0.3. The failure in CWR was shown to occur numerically in the midsections of the workpiece, where the stress triaxiality was maximum. The determined cruciform shaped crack also agreed with the experimentally observed crack shape. Finally, it was shown that the final microstructure of the workpiece was greatly affected by the workpiece initial temperature.