CEMENTED CARBIDE BODY WITH IMPROVED HIGH TEMPERATURE AND THERMOMECHANICAL PROPERTIES

摘要

According to the invention there is now provided a cementedcarbide grade for rock excavation purposes with 96-88 % WC,preferably 95-91 wt-% WC with a binder phase consisting of only Coor Co and Ni, with maximum 25% of the binder being Ni, possiblywith small additions of rare earth metals, for example Ce and Y,up to max 2% of the total cemented carbide. The WC grains arerounded because of the process of coating the WC with Co, and notrecrystallized or showing grain growth or very sharp corneredgrains like conventionally milled WC, thus giving the bodiesaccording to the invention surprisingly high thermal conductivity.The average grain size should be 8-30 µm, preferably 12-20 µm. Themaximum grain size does not exceed two times the average valueand no more than 2 % of the grains found in the structure areless than half of the average grain size.