Thixoforming : Semi-solid Metal Processing

Figure 10.35 Experimental and simulated temperatures at middle
and flange of the component after three cooling steps (ABAQUS).
ing the narrow temperature interval of the thixoforming process, a preheated tool
material with low heat conductivity would be preferred for the component regarding
the material flow during the forming operation. Accordingly, heat losses could be
minimized. Concerning the tool and its concept, a material with contrasting
properties would be preferred to ensure lower temperature gradients of the dies
for extending the tool life [23, 53, 54].
10.5
Conclusion
10.5 Conclusionj405
Compared with the conventional route of drop forging, the process technology of
forging metals in the semi-solid state shows potential with regard to the geometric
complexity of the components, material savings and lower energy consumption of the
required aggregates. Although the process requires only one forming step, it has an
increased cycle time compared with the drop forging process because of solidification
of the liquid-phase fraction. Efficient casting technologies are another strong competitor
for the semi-solid forging technique in the area of aluminium components.
Consequently, a possible niche for thixoforging production is not to be found in mass
production but in special applications such as the described joining operations.
However, analogous to thixocasting, adapted tool concepts have to be developed that
ensure a higher durability, especially for economic thixoforging of steel components.
The application of the rheo-route shows further savings potential. The expensive
induction heating unit can be economized and the process can be shortened. The
experiments show similar results to the thixoforging route. Numerical process
modelling will be a helpful development tool by providing a deeper insight into
metal flow and temperature field development.