High temperature oxidation and tribological properties of cemented carbide material under different cooling condition

For further clarify the correlation mechanism between the high temperature oxidation and tribological properties of cemented carbide, two groups of test samples of YT15 cemented carbide were prepared and heated to 500 °C ~ 900 °C, then cooled to room temperature in air and cutting fluid medium respectively. The surface morphology, oxidation characteristics, hardness, wettability, and tribological property were measured with white light interferometer, XRD instrument, contact angle measuring instrument, and MWF-500 friction tester. Experimental results indicate that the surface roughness and oxidation degree are increased with the increasing of heating temperature and independent of the cooling medium. Thus, a decrease law of friction coefficient and a worsening trend of surface wear quantity are observed due to low surface hardness under dry friction condition . For cutting fluid lubricating case, the friction coefficient of test sample is firstly decreased with the heating temperature increasing, and then an increased trend is occurred when the heating temperature is more than 800 °C. The main reason is that more wear particles are produced due to the low surface hardness and big contact pressure which deteriorated the lubrications conditions. The main contribution of this work is in providing a reference resources for the tool surface wear mechanism.