Types of Cutting Tool Materials and Their Properties

Hello friends, Today I am going to tell you different types of cutting tool materials which is widely used in different types of tool like drill bits, milling cutter, grinder, reamer and so on.

In addition, we will also learn about properties of cutting tool materials.

Cutting tools are used in manufacturing machineries like lathe machine, drilling machine , milling machine, etc.
Where they perform many operations.

A variety of tool materials are used as cutting tools in the metalworking industry, from high carbon steel to ceramic and diamonds. This does not mean that the most expensive tool will be the best tool. The best tool is one that is carefully chosen quickly, efficiently and economically.  

Mostly cutting tool materials can be categories into two groups first one is Stable and second one is Unstable materials.

Unstable materials;  These are usually low hardness steel.  Hardness is increased by heat treatment. 

But by increasing the hardness, the original toughness decreases slightly.  Because they generate heat, they are inherently unstable in material machining conditions.  

Stable Materials;  These materials remain relatively stable under the heat generated in most machining operations. They are worn out due to abrasion. 
But usually their properties do not change during the experiment.  These materials are quite rigid.  
Therefore, to avoid meeting the cutting edge, they are made slightly blunt.

So without wasting time let's know about different types of cutting tool materials and their properties.

Types of Cutting Tool Materials

Mostly cutting tool materials which are used to making the cutting tool can be divided into following types
  • High Carbon Steel
  • High Speed ​​Steel
  • Cemented Carbides 
  • Stellite
  • Ceramics
  • Diamond

Types of Cutting tool materials
Cutting Tool

High Carbon Steel

Initially, all tool bits were made of high carbon steel, which was properly hardened and tempered. 
These contain small amounts of silicon, chromium, manganese and vanadium to refine 0.6–1.5% carbon and grain size.  

The maximum hardness is approximately HRC 62.  

This materials wear resistance and hot hardness is very low. Gradually these materials have been replaced by high speed steel, cobalt steel, carbide steel, etc.  

High Speed ​​Steel

High speed steel was first produced in the 1900s. They contain very high concentrations of vanadium, cobalt, molybdenum, tungsten and chromium. This increases the ability to maintain hot hardness in hot conditions and wear resistance. They can be hardened to various depths with proper heat treatment. Cobalt makes this material warmer than carbon steel.

Provide much greater ability to maintain stiffness in the state. The high toughness and good wear resistance make high speed steel suitable for all types of cutting tools of complex size at relatively moderate cutting speeds. Nowadays, the most commonly used tool for taps, drills, reamers, gear tools, end cutters, slitting, brochures, etc. is using high speed steel material.  

Cemented Carbides

Use of these materials started in the 1930s. These are the most important tool materials nowadays due to their high hot hardness and wear resistance in hot state.  

The disadvantage of cemented carbides is that has low toughness. 

These materials are produced from powder metallurgy by sintering tungsten carbide grains in cobalt matrix. 
In addition to tungsten carbide, the mixture may contain other carbides such as titanium carbide (TIC) and or tantalum carbide (Tac). 

Cemented carbide is available in various sizes as inserts. They are mechanically coupled to the tool holder by clamps or brazed with tool holders.

Benefits of Tungsten Carbide Over High Speed Steel

There are following benefits of tungsten carbide

•Tungsten carbide can work at higher speeds than high speed steel.  

• Tungsten carbide is more economical for machining large quantities of parts.  

• Tungsten carbide tools can quickly remove metal and also give a good surface finish.  

Disadvantages of Tungsten Carbide Compared to High Speed Steel 

Following disadvantages contained tungsten carbide when compared to high speed steel

• Tungsten carbide is more expensive.  

• Tungsten carbide tools can only be grinded on a diamond grinding wheel. 

 • To use tungsten carbide tools, the machine and fittings must be very firm.  

Stellite

It is a cast non-ferrous alloy containing 43 to 48% cobalt, 17 to 19% tungsten, 30 to 35% chromium and 2% carbon.

Its benefits are: It is very hard and can be used for heavy cuts. It does not lose its temper even at red-hot (around 1,000 ° C) temperature. It is very expensive tool materials.  

Ceramics

Ceramics materials are made of fine-grain, high purity aluminum oxide (Al2O3) without pressurizing and sintering. 

These are available in two types

  1. White or Cold-Pressed Ceramics
  2. Black or Hot-Pressed Ceramics

White or Cold-Pressed Ceramics

White or cold-pressed ceramics have pressurized inserts and only aluminum oxide (Al2O3) sintering at high temperatures.  

Black or Hot-Pressed Ceramics 

This material contains 70% AI, O, and 30% Tic.

Both types of ceramics materials are suitable for continuous operation such as finish turning of cast iron and steel at very high speeds. 

Diamond 

Diamond is the most hardened material.
It is used for finishing and cutting of very hard materials like mirror, ceramics, etc.

Properties of Cutting Tool Materials

The material properties of each cutting tool materials are different, which are following

Carbon Tool Steel Material

There are following properties of Carbon tool steel 

• Unstable

• Cheap

• Heat sensitive 

• Mostly obsolete but still used for tap and die, hacksaw blades and reamers

• Hardness up to around HRC 65

• Fast cutting edges possible

High Speed Steel Material

High speed steels contained following properties

• Unstable 

• Retain hardness at moderate temperatures.

• Now the most commonly used cutting material

 • Used extensively for drill bits and taps 

• Hardness up to HRC 67 

• Fast cutting edges possible

HSS Cobalt Material

Properties of HSS Cobalt are following

• Unstable 

• Medium cheap

• Resistant to heat and therefore excellent for machining of abrasive materials such as titanium and stainless steel

• Extensive use for milling cutters and drill bits

• Hardness up to approximately HRC 70

• Fast Cutting edge possible

Cast Cobalt Alloy Material

Cast cobalt alloy properties are

• Stable 

• Costly 

• High machining speed due to low hardness

• Not much use 

• Hardness up to around HRC 65 

• Fast cutting edges possible

Cemented Carbide Material

Properties of Cemented Carbide are following

• Stable 

• Moderately expensive

• Highly used in industry

• High resistance to abrasion

• Used for turning tool bits, milling cutters and saw blades 

• Hardness up to HRC 90. 

•Fast edges are generally not recommended.

Ceramics Material

Ceramics properties are

• Stable 

• Medium cheap

• Resistance to extreme heat 

• Desirable in high speed applications

• Most common ceramics based on alumina (aluminum oxide), silicon nitride and silicon carbide

• Almost completely in use for turning tool bits

 Hardness approx. HRC up to 93 

• Away from sharp cutting edges and positive rake angles

Cermets Material

Cermets properties are following

• Stable 

• Moderately expensive 

• Based on titanium carbide and as nickel binders 

• Higher abrasion resistance than tungsten carbide

• Mainly used in turning tool bits

• Hardness up to HRC 93

• Fast edges not recommended

Diamond 

Diamond properties are following

• Stable 

• Very valuable

• Most rigid material

• Very high resistance to abrasion 

• Used as coating on turning tool bits and on many types of tools

• Sharp edges are not recommended.


So friends here we known about types of cutting tool materials and their properties.
I hope you all enjoyed these topics.


Thank You.

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