Abstract:Thermal fatigue and high temperature wear are the two principle failure mechanisms for thixoforming dies. Samples of Inconel 617 and Stellite 6 alloys were submitted to thermal cycling under conditions which approximate thixoforming of steels and to sliding wear tests at 750 °C. The experimental results thus obtained were compared with those of the X32CrMoV33 hot work tool steel. The Inconel 617 and Stellite 6 samples are much more resistant to oxidation and to softening than the hot work tool steel, providing a superior resistance to thermal fatigue cracking. The wear resistance of the Inconel 617 and Stellite 6 alloys at 750 °C is also markedly superior. The adhesive oxides growing slowly on Inconel 617 and Stellite 6 alloys sustain the wear action without spalling and are claimed to be responsible for the superior wear resistance of these alloys at 750 °C.

Key words: steel; thixoforming; tooling; thermal fatigue; wear