Cemented carbide, also known as tungsten carbide (WC) composite, is classified based on composition, grain size, binder material, and application. The main types include:
1. Tungsten Carbide Composition:
• Tungsten Carbide (WC): The main hard phase. It provides the material with its hardness and wear resistance.
• Cobalt (Co): The most common binder metal, which helps to hold the carbide grains together, offering toughness and impact resistance.
• Nickel (Ni), Chromium (Cr), and Iron (Fe): Sometimes used as binder metals for specific applications, as they provide better corrosion resistance and higher temperature
2. Binder Metal Types:
The binder metal in tungsten carbide is critical for defining the
toughness, thermal properties, and wear resistance. The main binder metals
include:
• Cobalt (Co): WC+Co binder
o Properties: Provides excellent toughness and ductility.
o Applications: Used in a wide range of general carbide applications, such as cutting tools, wear parts, and machining inserts and mining tools.
o Downside: It is prone to oxidation at higher temperatures.
• Nickel (Ni): WC+Ni binder
o Properties: Adds corrosion resistance and improved high-temperature performance compared to cobalt.
o Applications: Used in medical tools, chemical-resistant and marine applications (e.g., oil &gas)and high-temperature machining.
o Downside: Slightly lower toughness than cobalt in some applications.
• Iron (Fe): WC+Fe binder
o Properties: Sometimes used for cost-effective carbide grades, though it provides less toughness and wear resistance than cobalt or nickel.
o Applications: Often found in less demanding applications. (Wear parts, industrial components)
• Nickel +Cobalt Alloys:
o Properties: Combining the properties of both nickel and cobalt, these alloys provide both toughness and high-temperature performance.
o Applications: Used for tools exposed to aggressive wear and thermal cycling.
• WC+TiC+Co(Tungsten Carbide+Titanium+Cobalt) - Better cutting Performance and Wear, Oxidation resistance (YT Series)
• TiC-Based (Titanium Carbide) - Contains TiC +Ni/Mo binder, ideal for high-temperature resistance, high magnetic environments and wear applications.
3. Classification by Grain Size
The grain size of tungsten carbide particles determines hardness and
strength.
• Ultrafine Grain (0.2 - 0.5 µm) - Used in precision cutting tools, drills, and micro-machining.
• Fine Grain (0.5 - 1.5 µm) - Offers high hardness and wear resistance, commonly used in end mills, inserts, and wear parts.
• Medium Grain (1.5 - 3.0 µm) - Balanced strength and toughness, ideal for general-purpose machining.
• Coarse Grain (3.0 - 6.0+ µm) - High impact resistance, used in mining tools, drilling bits, and forming dies.