Effect of guiding angle on metal flow and defects in extrusion deformation

In order to reduce defects, such as the dead zone, the shrinkage cavity and the surface cracks, caused by non-homogeneous metal flow in extrusion process, an extrusion process is proposed by using a die with the guiding angle. Numerical simulation is carried out on the metal flow of extrusion process with and without a guiding angle. It is shown from simulation results that the stress distribution at the lower corner of the bottom die is optimized and the dead zone is decreased as there is the guiding angle. The inhomogeneous equivalent strain is improveds in the container at the final stage of extrusion, which reduces possibility of generation of shrinking hole at the end of the axis. The stress condition of the farthest point from the axis at the exit is changed, and the axial stress is decreased by half, so that the risk in generation of surface cracks caused by additional stress is greatly reduced.