Different Types of Steel and their Classification

Metallic materials can be divided into broadly two types: a) Ferrous and b) Non-Ferrous. Ferrous materials contain more than 70% of Iron in them; and Non-Ferrous are materials which are not Iron based. Ferrous materials consist of Pure Iron, Wrought Iron, Cast Iron and Steel. From applications point of view, Steel have the most desirable properties among them. In this article, we summarize different types of Steel according to their composition and applications.

Classification according to Composition

Now Steel can be grouped majorly into:

1) Plain Carbon Steel
2) Alloy Steel

When Steel is made without any intentional addition of alloying elements, it is called Plain Carbon Steel. When alloying is done of elements like Copper, Nickel, Chromium, Manganese, etc. for developing specific properties, it is called Alloy Steel. Making Alloy Steel is a difficult and expensive process as the quantity of alloying needs to be strictly controlled.

Percentage of Carbon in Steel makes a lot of difference in Steel properties and applications. Plain Carbon Steel can be grouped according to the amount of carbon present in them:

1) Low Carbon Steel: Carbon content limited to around .20%
2) Medium Carbon Steel: Carbon content limited to around .20% to .60%
3) High Carbon Steel: Carbon content ranging from .60% to 1.0%. In some cases, can go up to 2.0%

Alloy Steels can be further grouped into a) Low Allow Steel, with alloy content of less than 5% and b) High Allow Steel, with alloy content greater than 5%.

Classification according to Shape and Applications

When grouped in terms of shape, there can be many types of Steel, for example: Sheets, Plates, Bars, Blooms , Billets, Beams, Channels, Tubes, Angles, Tees, Flats, Wires etc. They can also be grouped as per their applications:

1) Sheet Steels, which contain carbon percentage below .10% for good cold formability and weldability.
2) Wire Rod Steels, where percentage of carbon is below .15%
3) Structural Steels, where carbon is in range of .10% to .25%. This includes Reinforced Steel Bars, Beams where high percentage of carbon helps in increased strength.
4) Engineering Grade Steels, where carbon is in range of .15% to .80%. They are used in engineering applications like machine parts, gears, shafts, etc.

This article provides a summarized view of types of steel and their classification. There are thousands of types of steel materials with different compositions, applications and shapes. In Steel, its composition plays an important role in deciding its properties and applications.