Thixoforming : Semi-solid Metal Processing

Figure 3.41 By means of Thermo-Calc calculated phase contents
of steel X210CrW12 in equilibrium.
with concurrent formation of M7C3 and M23C carbides take place (Figure 3.41). This
diffusion-controlled cooling rate is, however, only observed at an adequately slow
cooling rate, as depicted in Figure 3.37b for cooling from a temperature of 980 Cbythe
pearlite nose . If, however, the austenite is stabilized at a higher annealing temperature
through the high solubility of carbon and chromium, not only does the Ms temperature
change but also the transformation kinetics differ, as shown in Figure 3.42 in form of a
Figure 3.42 CCT diagram for steel X210CrW12 for different
cooling rates from 1210 C after an annealing of 30 min at 1270 C.
The enlarged partial image illustrates the transformation induced
change in length of sample 4.4. The numbers used correspond to
the experimental conditions in Table 3.7.
3.6 Microstructure Analysis and Material Propertiesj91