cutting tool materials

1. Course code ME3493 Course name Manufacturing Technology
Year/sem 2/4 Unit no 1
Course Instructor: M.Karthikeyan AP/Mech
UNIT 1 MECHANICS OF METAL CUTTING
Mechanics of chip formation, forces in machining, Types of chips, cutting
tools – single point cutting tool nomenclature, orthogonal and oblique metal
cutting, thermal aspects, cutting tool materials, tool wear, tool life, surface
finish, cutting fluids and Machinability
Cutting tool materials
Cutting tool materials are essential components in machining processes,
designed to shape or remove material from a workpiece.
The choice of cutting tool material depends on various factors such as the
 type of material being cut,
 cutting conditions,
 tool life requirements, and
 cost considerations.
Here are some common cutting tool materials:
1. High-Speed Steel (HSS):
 High-speed steel is a classic cutting tool material known for its high
hardness and excellent wear resistance at elevated temperatures.
 It contains tungsten, chromium, molybdenum, and vanadium,
among other elements.
 HSS tools are suitable for cutting operations at moderate speeds and
temperatures.
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2. 2. Carbide (Tungsten Carbide):
 Carbide tools are made from tungsten carbide particles bonded with
cobalt.
 Carbide offers superior hardness and wear resistance compared to
HSS,
 It is suitable for high-speed machining of tough materials like steel, cast
iron, and non-ferrous metals.
3. Ceramics:
 Ceramic cutting tools are made from compounds like alumina (Al2O3),
silicon nitride (Si3N4), or silicon carbide (SiC).
 Ceramics offer exceptional hardness, high-temperature resistance,
and chemical inertness.
 They are ideal for machining hardened steels, cast iron, and superalloys
at high speeds.
4. Cemented Carbides:
 Cemented carbides, also known as hard metals, consist of tungsten
carbide particles embedded in a metallic binder such as cobalt.
 They offer high hardness, excellent wear resistance, and
toughness.
 It is suitable for cutting operations in various materials, including
stainless steels, titanium alloys, and composites.
5. Cubic Boron Nitride (CBN):
 CBN is a synthetic material with exceptional hardness and thermal
stability, second only to diamond.
 CBN cutting tools are mainly used for machining hardened steels, cast
irons, and superalloys at high speeds and temperatures.
6. Diamond:
 Diamond is the hardest material known, offering excellent wear
resistance and cutting ability.

3.  Diamond cutting tools are primarily used in non-ferrous materials,
ceramics, and abrasive composites.
 However, due to its high cost and limited thermal stability at high
temperatures, diamond tooling is less common compared to other
materials.
7. Coated Tools:
 Various cutting tool materials can be coated with thin layers of hard
materials such as titanium nitride (TiN), titanium carbonitride (TiCN),
or aluminum oxide (Al2O3).
 These coatings enhance tool life, reduce friction and improve chip
evacuation during machining processes.
8. Carbon Tool Steel
 carbon steel is used for low-speed machining operations.
 Abrasion resistance and the ability to keep a sharp cutting edge are two
advantages of high carbon steels.
 Carbon tool steels have high machinability.
 Carbon steel starts melting at a temperature of approx. 180 – 250
degrees. As a result, it is unable to operate at high temperatures.
9. Sialon
 Sialon (Silicon, aluminium, oxygen and nitrogen) grades are well-suited
for cutting operations on heat resistant super alloys (HRSA), as they
offer both the strength of a self-reinforced silicon nitride network and
improved chemical stability.
The selection of the appropriate cutting tool material depends on the specific
requirements of the machining operation, including the material being cut,
cutting speed, feed rate, depth of cut, and desired surface finish. Additionally,
advancements in material science continually introduce new cutting tool
materials with improved properties to meet the demands of modern
machining processes.