I. Hardness
Due to the high temperature of WC, TiC, etc., the hardness of the alloy is also high, generally between 89-93HRA. The hardness of cemented carbide decreases with increasing temperature. At 70-80 degrees Celsius, most cemented carbides maintain the normal temperature hardness of high speed steel. The high temperature hardness of alloy mainly depends on the hardness of carbide at high temperature, so the high temperature hardness of WC-TiC-Co alloy is higher than that of WC-Co alloy. Adding TaC(or NbC) can improve its high temperature hardness.
Two, variable strength and toughness
The bending strength of cemented carbides used at room temperature is in the range of 0.9-1.5GPa. The higher the binder content, the higher the bending strength. The bending strength decreases with the increase of TiC content. Hard alloy is a brittle material, its impact toughness is only 1/30-1/8 of high speed steel. Poor toughness is a major weakness of cemented carbide. Therefore, carbide cutting tools generally weld or clamp the alloy blade on the tool body, for complex tools to make a whole. WC-TiC-Co is similar to the class WC-Co.
3. Thermal conductivity
Since the thermal conductivity of TiC is lower than that of WC, the thermal conductivity of Wc-TIC-Co alloy is lower than that of WC-CO alloy and decreases with the increase of TiC content. The thermal conductivity of YG6 is more than double that of YT15.
Four, line expansion coefficient
The linear expansion coefficient of cemented carbide is much smaller than that of high speed steel. The linear expansion coefficient of WC-TiC-Co alloy is greater than that of WC-Co alloy, and increases with the increase of TiC content.
Five, cold welding resistance
The cold welding temperature of hard alloy and steel is higher than that of high speed steel, and the cold welding temperature of WC-TiC-Co alloy and high speed steel is higher than that of WC-Co alloy.
