CAD/CAM Concepts Material Science MECHANICAL THEORY

Different Types of Steels-Stainless steels, Chemical Composition,Applications, Properties etc.

Different Types of Steels-Applications, Chemical Composition, Stainless steels, Properties etc.:Steels are widely used materials in  industry. They are the alloys of iron, carbon and other elements such as silicon, phosphorus, sulphur and manganese. The carbon present in the form of iron-carbide(Fe3C) increases the hardness and strength of the steel.

Steels are classified based on their their chemical composition, applications and methods of production.

Different Types of Steels:

Chemical composition:

Steels can be classified based on 

Carbon Content

  • Low Carbon Steel
  • medium Carbon Steel
  • high Carbon Steel

Method of manufacture of Steels

  • Bessemer steel
  • Electric furnace steel
  • Open – hearth steel
  • Crucible steel.

Let’s discuss about types of steels based on composition

  1. Low Carbon Steels(L.C.S)
  2. Medium Carbon Steels(M.C.S)
  3. High Carbon Steels(H.C.S)

The explanation is as follows…

1.Low Carbon Steels:

  • Composition- 0%C to 0.25 % C.
  • Micro structure- Predominantly  α – ferrite and small quantities of pearlite.
  • Properties – outstanding ductility and toughness. good machinability and weldability, high formability, toughness , high ductility etc.

Ex: Mild steel.

  • Advantages: least expensive to produce.
  • Disadvantages: Martensite is difficult to form owing  to very low carbon content.
  • Applications: Automobile body components, structural shapes, pipes, sheets etc.

2.Medium Carbon Steels:

  • Composition: from 0.25% to 0.55% C.
  • Microstructure : α – ferrite and pearlite.
  • Properties: stronger than low – carbon steel but less tougher than it.
  • Advantages: Best range for adding alloying elements.
  • Applications: Railway wheels & tracks, gears etc.

3.High carbon steels:

  • Composition: from 0.55% up to 2.1 % C
  • Microstructure: Fe3C,Pearlite(C >0.8%), – ferrite and pearlite (C < 0.8%).
  • Properties : hardnest, strongest and least ductile compared to Low carbon steels.
  • Advantages : to make tool steels.
  • Applications: Knives, hack saw blades, chisels, hammers, drills, dies, machine tool cutters, punches etc.

Applications of steel:

As Steel has high tensile strength, it was used in

  • Construction of buildings
  • Infrastructure
  • Tools
  • Ships
  • Automobiles
  • Machines & appliances
  • Weapons
  • Machine steel
  • Spring steel
  • Boiler steel
  • Structural steel
  • Tool steel etc.

Some of the other types of steels are as follows.

Shock-resisting Steels: These steels can resist fatigue loads and shock loads.

High strength Steels: Applied where Low weight and high strength are required.

Tool Steels: These are mainly used for making Tools and Dies for cutting, forming and forging metals in their hot or cold conditions.

Spring Steels: used for making Coiled and Leaf springs.

Heat Resistant Steels: These steels can resist corrosion, oxidation and creep at higher working temperatures.

Ex: furnace

This is the detailed explanation of different types of steels.Now let’s discuss about Stainless steel, its properties and types along with the chemical composition.


Different Types of Steels-Stainless Steel:

Stainless steels are also known as corrosion resistant steels.

Stainless steel is an alloy of Iron with a minimum Chromium percentage of 10.5%. 

Chromium produces a thin oxide layer on the surface of steel known as the ‘passive layer’. which prevents further corrosion of the surface.

Chromium is the principal alloying element in stainless steel and the rest of the elements are  nickel, manganese etc. Which are present in small amounts.

Stainless Steels types:

These are usually classified as: 

1.Martensitic

2.Ferritic and 

3.Austenitic

Let’s discuss….

1.Martensitic Stainless steels:

  • They have high strength, toughness but lesser corrosion resistance than austenitic and ferritic grades.
  • These are magnetic also. 

Applications:  Moulds, bearings,cutlery, surgical implements, turbine blades and some aircraft components.

2.Ferritic stainless steels:

  • They have higher strength but moderate corrosion resistance. 

Applications: These are used for Automobile rims, exhaust systems and heat transfer equipment’s for chemical and petrochemical industries.

3.Austenitic stainless steels:

  • They have stable structure and properties from high to low temperatures.
  • These are used where toughness and corrosion resistance are of primary concern.

Applications: Pump Components, shafts, fasteners, equipment for chemical, food and diary industries.

Properties of Stainless steel:

  • High ductility and formability.
  • High corrosion resistance.
  • Good creep resistance.
  • Good weldability
  • Good thermal conductivity.
  • Good machinability.
  • High hot and cold workability
  • Wide range of strength and hardness
  • Excellent surface appearance and finish.

 ——————-

Effect of Alloying elements in Steels:

The effect of alloying elements in steel are as placed below in the form of image.

Effect of Alloying elements in Steels
Effect of Alloying elements in Steels

These are the different types of steels used in various applications. If you have any doubts, feel free to ask from the comments section.For further information, you can visit our blog regularly.

Read:

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.