Thixoforming : Semi-solid Metal Processing

Figure 11.5 Shamrock-like thixoextrusion die.
should be in a semi-solid state to take advantage of thixotropic behaviour, and (ii) the
solidification zone, in which homogeneous and rapid cooling of the extruded bars is
desired.
The respective boundary temperatures are defined by the envisaged liquid-phase
content and the solidus temperature of the work alloy. In the case of X210CrW12
(AISI D6), the target value for the container was set to 1300 C, corresponding to a
liquid-phase content of approximately 55% (see Chapter 3). The steel grade
X210CrW12 was selected as work material owing to its suitability for semi-solid
processing (cf. Chapter 3). At the onset of forming, that is, at the die land inlet, the
material should still be in a semi-solid state; hence at this point the steel temperature
Table 11.1 Tool dimensions as applied isothermal laboratory thixoextrusion tests.
11.4 Isothermal Thixoextrusionj419
Container
Material Al2O3, 99.7%
Inner diameter [mm] 34
Outer diameter [mm] 50
Cross-sectional area [mm 2 ] 907.9
Wall thickness [mm] 8
Height [mm] 150
Die
Material Al2O3, 99.7%
Cross-sectional area [mm 2 ] 108.4
Extrusion channel length [mm] 13.3
Feeding angle [ ] 52
Extrusion ratio 8.4