Carbide-Tipped Cutting Tools

Carbide-tipped cutting tools are widely used in various machining operations due to their hardness, wear resistance, and high cutting speeds. These tools are typically manufactured using the powder-metal technology process and have a specific composition.

Composition of Carbide-Tipped Cutting Tools

The correct answer, option 'B', states that carbide-tipped cutting tools have a composition of tungsten carbide-cobalt in the ratio of 90% - 10%. This means that 90% of the tool is made up of tungsten carbide, while the remaining 10% is cobalt.

Tungsten Carbide

Tungsten carbide (WC) is a hard compound composed of tungsten (W) and carbon (C). It is renowned for its exceptional hardness and abrasion resistance. Tungsten carbide is one of the hardest materials known, surpassing even the hardness of many types of hardened steel. Due to its hardness, it is widely used as a cutting tool material.

Cobalt

Cobalt (Co) is a metallic element that is commonly used as a binder material in tungsten carbide cutting tools. It acts as a binding agent, holding the tungsten carbide particles together and providing additional toughness to the tool. Cobalt also helps in improving the tool's resistance to fracture and wear.

Powder-Metal Technology Process

The powder-metal technology process is commonly used in the manufacturing of carbide-tipped cutting tools. It involves a series of steps including powder preparation, mixing, compacting, and sintering.

1. Powder Preparation: The tungsten carbide and cobalt powders are prepared separately by crushing and grinding the raw materials. The powders are then carefully measured and mixed to achieve the desired composition.

2. Mixing: The tungsten carbide and cobalt powders are thoroughly mixed together to ensure a homogeneous distribution of the carbide particles within the cobalt matrix. This step is crucial to achieve the desired properties of the cutting tool.

3. Compacting: The mixed powders are then compacted into the desired shape using specialized presses. The compacted shape is often referred to as a green body.

4. Sintering: The green bodies are subjected to a high-temperature sintering process in a controlled atmosphere. During sintering, the powders are heated to a temperature below their melting point, causing the tungsten carbide particles to bond with each other and with the cobalt matrix. This results in the formation of a dense and solid carbide-tipped cutting tool.

Conclusion

Carbide-tipped cutting tools are manufactured by the powder-metal technology process. The correct composition for these tools is tungsten carbide-cobalt in the ratio of 90% - 10%. Tungsten carbide provides hardness and wear resistance, while cobalt acts as a binder, improving toughness and resistance to fracture. The powder-metal technology process involves powder preparation, mixing, compacting, and sintering to produce the final carbide-tipped cutting tools.