Thermal Fatigue Failure of a CrN-Coated Restrike Punch
A CrN coated restrike punch was made of WR-95 (similar to H-11), which was fluidized bed nitrided. The coated punch was used on hot Inconel at about 1040 deg C (1900 deg F). However, a water-soluble graphite coolant was used to maintain the punch temperature at 230 deg C (450 deg F). Visual and binocular inspection at 64+ revealed presence of cracks and complete washout of coating in the working area of the failed punch. Comparison of metallographic cross sections of used and unused punches revealed a significant microstructural transformation in case of the used punch. Presence of a...
Suranjeeta Dhar, Fameeda Mohammed, Laura Xu, Raymond Fontana, Thermal Fatigue Failure of a CrN-Coated Restrike Punch, ASM Failure Analysis Case Histories: Machine Tools and Manufacturing Equipment, ASM International, 2019, https://doi.org/10.31399/asm.fach.machtools.c9001574
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