EXPERIMENTAL SIMULATION OF METAL FLOW IN PORTHOLE-DIE EXTRUSION

The metal flow in the extrusion of a pipe through a porthole-die has been analyzed experimentally, regarding the process as a combination of multi-hole die and multi-billet extrusions. The distorted grid patterns on some symmetrical planes of metal flow were observed continuously using a split-tool assembly and split specimens having square grids inscribed on their surfaces, the distribution of particle velocity being determined from the grid distortion observed. In the so-called welding plane, a symmetrical plane of metal flow, the region where welding occurs is actually located near to the die exit and occupies only a small area. To inspect the reliability of simulation results, the extrusion of A1050 pipe through a porthole-die was carried out, metal flow in the container and in the welding chamber being investigated by macro etching.