Kovametalli

Kovametalli, or kovametallit in plural, is a class of artificial composite materials known in English as cemented carbide or hard metal. It consists of hard carbide particles, most commonly tungsten carbide (WC), bound together by a metal binder, typically cobalt. The result is a material that combines extreme hardness and wear resistance with a degree of toughness from the metal binder.

The typical composition is WC particles dispersed in a cobalt binder, sometimes with additives such as nickel, iron, or carbide-forming elements like TiC, TaC or NbC to tailor properties. The material is produced by powder metallurgy: carbide powder and binder powder are mixed, pressed into shapes (such as inserts or end mills), and sintered at high temperature. Post-sintering treatments and coatings may further enhance performance.

Key properties include very high hardness, excellent wear resistance, and good hot hardness, enabling cutting, drilling and shaping at elevated temperatures. However, kovametallit have relatively low fracture toughness compared with many metals, and their toughness is strongly influenced by binder content and grain size. Grades vary from fine-grained for higher hardness to coarser-grained for better impact resistance.

Common applications are in cutting tools, drilling tools, milling inserts, dies and punches, and wear parts used in machining steel, cast iron, non-ferrous alloys, and challenging materials. Tool manufacturers produce a wide range of grades, with different grain sizes, binder contents, and coatings to match specific machining conditions.

Safety considerations include handling fine carbide powders, which can be a health hazard and pose dust/explosion risks if improperly managed.