Cemented carbides tools are normally manufactured via ________.

Question

Question

This question was previously asked in

NHPC JE Mechanical 6 April 2022 (Shift 1) Official Paper

Answer 1

Explanation:

Cemented carbides (Carbides):

Carbides are used for tool material because of their high hardness over a wide range of temperatures, high elastic modulus, high thermal conductivity and low thermal expansions.
These tools are being developed to meet the challenges for increasingly high speed.
These tools cannot be used at low speeds as at low speed the chips of workpiece material are welded to the surface of the tool and increases its wear.
Carbides, which are nonferrous alloys, are also called, sintered (or cemented) carbides because they are manufactured by powder metallurgy techniques.
Most carbide tools in use today are either straight Tungsten carbide (WC).
The other major constituent of sintered carbide tool is mainly binder, mainly cobalt or Nickel.
These bonders have relatively low melting points and can exist in liquid form at the sintering temperatures.

There are two types of carbides:

Tool material	General characteristics	Modes of tool wear or failure	Limitations
Uncoated carbides	High hardness over a wide range of temperatures, toughness, wear resistance, versatile, wide range of applications	Flank wear, crater wear	Cannot be used at low speeds because of cold welding of chips and microchipping
Coated carbides	Improved wear resistance over uncoated carbides, better frictional and thermal propertied	Flank wear, crater wear	Cannot be used at low speeds because of cold welding of chips and microchipping