Development of New Types of Carbides with Ultrafine and even Finer Tungsten Carbide Powders

摘要

Development trends for carbide grades have tended for years towards reducing the average tungsten carbide grain size in order to fulfill the demands of the round tool industry. The influence of the WC particle size on the physical properties of cemented carbide, especially on hardness and toughness, is explained. Reduced grain sizes require adjusted production methods starting from the WC powder to finished carbide tools. All steps starting with the characterization of the raw material until the improved sinter and HIP conditions for carbide rods are described. The special needs for manufacturing plastified carbide powders from ultrafine and even finer WC powders, particularly the influence of increased milling times on the toughness of the carbide, are emphasized as well as the use of advanced extrusion processes with screw extrusion extruders for efficient rod production.