The effect of gate shape on the filling limitation in the semi-solid forging process and the mechanical properties of the products

To obtain high quality components with the semi-solid forging process, it is important to obtain a homogeneous distribution of solid particles without liquid segregation. In the closed-die semi-solid forging process, liquid segregation is strongly affected by injection velocity than process parameters such as the pressure and the solid fraction, because the material has to travel a relatively long distance to fill the cavity through a narrow gate before solidification begins. To investigate the effect of gate shape on the filling phenomenon in the semi-solid forging process, two kinds of gate shape system are proposed. A filling test for the two kinds of gate systems was carried out. Therefore, in this study, the optimal injection velocity and die temperature were investigated to fabricate a near-net-shape compressor component called an Al frame. For uniformity of the solid particles, the injection velocity has to be higher than 160 and 370 mm/s to produce sound part without filling defects, in the range of die temperature of from 200 to 300 °C. In addition, the mechanical properties for a forged semi-solid component with a good filling situation were tested with the specimen before and after heat treatment.