THERMAL FATIGUE AND SOFTENING BEHAVIOR OF HOT WORK TOOL STEELS

The present paper concentrates on the thermal fatigue and so ftening behavior, which are the most relevant damage mechanisms in tools for ho t working applications. A new thermal fatigue testing facility, which is based on a pu lsed diode laser as surface heating source, is used to characterise the thermal fatigue behavior of a hot work tool steel. Various temperature cycle s are applied to study the effect of the maximum temperature, the temperat ure range and the heating time. To prevent undesired oxidation of the samp le the tests were