| Summary: | 碩士 === 國立臺灣大學 === 機械工程學系 === 86 === The Falex machine is used to perform the pin-on-disc tests of
tool steel SK3. By observing the oxide film on the surface, a prediction
model is presented to relate the wear rate to the input load. Its
explanation is also included in this article.
To distinguish the mild and severe oxidational wear, besides of
gathering the recording temperature and the height of the pin, the surface
roughness and profile equipment is also used to observe the pin-on-disc
tests. All the results above are closely related to the thickness of oxide.
To calculate the real contact temperature, the oxide thickness and the
hot hardness declining factors are considered. Combine the two factors,
and compare with the melt point and transition temperature. It comes to a
reasonable prediction of the flash temperature.
By cutting the pin and using the microscopic, we can measure the
thickness of the oxide film. An exponential fitting curve is used to relate
the thickness of oxide to the load. Putting the factor of oxide thickness
into the process of prediction model, the wear rate is determined. Compare
the prediction with the experimental results, the difference is small only
over some restricted nominal stress, in other words, where the mild
oxidational region dominate. The experimental prediction model is not
applicable when not in the mild oxidational region.
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