Numerical calculation of the thermal load during the thixoforming of steel and of the tool life.

半固态金属的成形是由于复杂的载荷分布对所用工具的高要求。除了机械应力之外，成形工具还暴露于由合金的初始温度（在固相线和液相线之间）和工具框架的最大预热温度引起的极端温度变化应力。在钢的触变成形的情况下，加工温度为约1300-1500 °C，而模具预热温度限于约300-500 °C，因为机器环境主要由钢组成。还有腐蚀模具表面的负载，特别是通过半固态合金的熔化阶段。此外，成形过程中的固相部分或从模具中取出时的固化组分会产生摩擦磨损。工具和工具成本在触变成形加工的总成本中占有很大份额。降低成本的一种方法是增加刀具寿命。这方面的一个重要贡献是在工艺设计和刀具设计期间通过使用有限元模拟来考虑刀具磨损。预测工具失效可以通过定制的工艺和工具设计来延长工具寿命。在拟议的资助期内，重点是预测由于热机械触变成疲劳而导致的工具失效。对物质行为的现实描述是必要的。因此，两相模型的材料行为的数值模拟必须在商业有限元软件中实现。

The forming of metals in the semi-solid state is due to the complex load profile high demands on the tools used. In addition to the mechanical stress the shaping tools are exposed to extreme temperature change stresses that result from the initial temperature (between the solidus and liquidus) of the alloys and in the maximum preheat temperature of the tool frame. In the case thixoforming of steels the processing temperature is about 1300-1500 °C while the mold preheat temperatures are limited to about 300-500 °C, since the machine environment consists mostly of steel. There are also loads of corrosive mold surface, in particular through the melting phase of the semi-solid alloys. Furthermore, there is a tribological attack by the solid-phase fraction during forming or by the solidified component during removal from the mold.The tools and tool costs have a significant share of the thixoforming the total cost of the part to be manufactured. One approach to cost reduction is increasing the tool life. An important contribution to this is taking the tool wear into account by using the finite element simulation during the process design and the tool design. The prediction of tool failure allows the increase of tool life through a customized process and tool design.The emphasis in the proposed funding period is the prediction of tool failure due to thermal-mechanical Thixoforming the fatigue. A realistic depiction of material behavior is necessary. Therefore, a two-phase model for the numerical simulation of material behavior has to be implemented in a commercial FE software.