Thixoforming : Semi-solid Metal Processing

3.3 Alloying Systemsj65
and with different bath temperatures during annealing can be found in the
literature [54, 55].
To reduce the danger of cracking in martensitically hardened components, an
isothermal transformation can be conducted in the lower bainite level which leads to
a tougher and more dimensionally stable structure without such a high hardness
[53, 56]. During the martensite hardening and the transformation into the
bainite level, different internal stress conditions develop [55]. A transformation in the
lowest bainite level has the advantage of no retained austenite, which delays
transformation that results in an undesired distortion of the components. Therefore,
bainitization has gained strongly increasing importance in relation to the improvement
of the dimensional stability of components [56]. The choice of the optimal
transformation conditions depends strongly on the alloy composition, where the
major disadvantage of bainitization is the longer processing time in comparison with
martensite tempering and thereby increases the costs.
Titanium in steel 100Cr6 results in a decrease in the fatigue life due to the
development of relatively small (