When evaluating Tungsten Carbide (WC) knives, the Cobalt (Co) content and grain size are critical. A lower cobalt content (e.g., 6%) increases hardness and wear resistance, while a higher content (e.g., 12-15%) improves toughness and impact resistance. You should also verify the Vickers Hardness (HV) or Rockwell Hardness (HRA) levels; high-quality industrial blades typically range between 89-93 HRA. Additionally, ensure the surface roughness (Ra) is minimized through precision grinding to reduce friction during high-speed cutting.