Full definition
Tungsten carbide (WC) is a remarkable composite material known for its exceptional hardness and durability, making it a preferred choice in various industrial applications. This material is created by sintering tungsten carbide particles in a metallic binder matrix, typically cobalt (Co), which constitutes about 3-25% by weight. The resulting hardness of tungsten carbide ranges from 1,300 to 1,700 HV (Vickers), positioning it as the second hardest material next to diamond for practical engineering uses. It exhibits impressive mechanical properties, including a compressive strength of 3,500 to 7,000 MPa and a transverse rupture strength varying from 1,000 to 4,000 MPa, influenced by the grain size and cobalt content. The more cobalt present, the tougher and softer the material becomes, allowing for a balance between hardness and toughness depending on the application requirements.
Tungsten carbide is categorized into three main grain sizes: fine grain (0.2-0.8 μm), suitable for precision cutting tools; medium grain (1-3 μm), designed for general-purpose applications; and coarse grain (3-6 μm), which is ideal for mining and wear parts. The material's versatility is evident in its wide range of applications, including cutting tool inserts for CNC machining operations such as turning, milling, and drilling, classified under ISO standards P, M, and K. Furthermore, tungsten carbide is extensively utilized in mining drill bits, wear nozzles, ball mill grinding media, and HVOF thermal spray coatings, which are employed in pump components, shafts, and valve seats, as well as seal faces.
The manufacturing process of tungsten carbide involves powder metallurgy, where WC powder is combined with a cobalt binder, then pressed and sintered at temperatures between 1,350-1,500°C. This process is crucial for achieving the desired density and hardness, making tungsten carbide suitable for high-performance applications. The recycling of tungsten carbide scrap has also become a well-established practice, allowing for the recovery and reuse of valuable materials, thereby enhancing sustainability in industrial processes. Brands such as Sandvik, Kennametal, Ceratizit, and Seco are recognized for their high-quality tungsten carbide products, contributing to advancements in cutting and wear-resistant technologies.