Abstract: (9004 Views)
In the present investigation effects of time and temperature on plasma nitriding behavior of DIN 1.2344 (AISI H13) steel are studied. Pulsed plasma nitriding process with a gas mixture of N2 = 25% + H2 = 75% and duty cycle of 70% is applied to cylindrical samples of DIN 1.2344 hot work tool steel. X-ray diffraction, surface roughness, microhardness and ball on disc wear test are performed and behavior of plasma nitrided samples are compared. Scanning electron microscopy and optical microscopy are used in order to observe the microstructure of samples after nitriding. XRD results showed that the compound layer is dual phase. Hardness near the surface dropped by rising the process temperature and it rose in longer process durations. The comparison of µ results showed frictional properties in longer durations with lower temperatures is approximately the same in higher temperatures with shorter durations.
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- The friction coefficient of DIN 1.2344 hot work tool steel after plasma nitriding was found 0.35.
- The thickness of the compound layer was more dependent on temperature of plasma nitriding.
- The diffusion layer played an important role on reducing the width of wear track.
- Increasing the time to 16 hours in plasma nitriding led to less surface roughness.