Thermal Fatigue Resistance of Nitrocarburized and Ion Nitrided H13 Steel

The thermal fatigue resistance of ion nitrided H13 and nitrocarburized H13 was studied.The specimens were analyzed by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS).The thermal fatigue resistance was tested.The results showed that after 1 000 cycles of thermal fatigue tests at 700 ℃,the surface of nitrocarburized H13 steel exhibited a small quantity of thermal fatigue cracks,while the thermal fatigue cracks on ion nitrided H13 suface formed network,and expanded into substrate about 300 μm in depth.The thermal fatigue cracks on the original H13 surface expanded slightly and extended into matrix about 100 μm.