Have you ever wondered about the difference between iron and steel? In that case, I will provide a detailed explanation.
To understand the difference, it's important to note that iron is a chemical element, while steel is an alloy made from a combination of elements, including iron and carbon.
Are you still feeling confused?
It is true that elements alone cannot create things. In reality, commonly used iron is actually an alloy, specifically a ferrocarbon alloy composed of iron and carbon.
What is the difference between steel and iron?
The difference between iron and steel is their carbon content.
Iron can be divided into two types: pig iron and wrought iron, which differ by their carbon content. The table below provides a comparison of their differences.
Iron and steel carbon content table
| Name | wrought iron | Steel | Pig iron |
| carbon content | <0.02% | 0.02%-2.11% | 2.11%-4.3% |
Iron with a carbon content of less than 0.02% is called wrought iron, while iron with a carbon content between 2.11% to 4.3% is called pig iron. Steel falls between these two categories.
Carbon content affects iron performance. The higher the carbon content, the harder the iron will be, but it will also become more brittle. On the other hand, iron with lower carbon content will be softer and have better ductility.
wrought iron
Wrought iron is a type of pure iron refined from pig iron. It has a carbon content of less than 0.02% and is also known as wrought iron or pure iron.
Wrought iron is soft, flexible and ductile, making it possible to draw it into wires of low resistance and hardness. Furthermore, it is easy to forge and weld.
Wrought iron usage:
Wrought iron has many uses due to its properties. For example, it has high magnetic permeability, making it a suitable material for electromagnetic applications, including various iron cores.
Additionally, wrought iron is also used as a deep drawing material as it can be molded into complex shapes, as seen in many beautiful crafts.
Pig iron
Pig iron, on the other hand, is hard, durable, and has good casting properties, but it is brittle and cannot be forged.
Depending on the form of carbon in pig iron, it can be divided into white iron, gray iron and spherical cast iron.
White iron:
White iron is a type of pig iron in which the carbon exists mainly in the form of iron carbide. Its section is white in color. This type of pig iron is hard and brittle and is commonly used as a raw material for making steel.
Gray iron:
When carbon exists in the form of flaked graphite, the fracture appears gray, and this type of pig iron is known as cast pig iron.
Due to the smoothness and lubricating properties of graphite, cast pig iron has good cutting and wear resistance as well as casting properties. However, it lacks sufficient tensile strength, so it cannot be forged or rolled, and is only suitable for making items such as machine tool bases and iron pipes.
Cast Iron Ball:
When carbon exists in the form of spherical graphite, it has significantly improved mechanical properties compared to gray iron and is comparable to steel.
Spherical cast iron has excellent casting, cutting and wear resistance properties, as well as some elasticity. It is widely used to manufacture crankshafts, gears, pistons and other advanced castings, as well as various mechanical parts.
Steel
Steel is the most used form in our daily life. Steel is an alloy that falls between pig iron and wrought iron and is commonly referred to as carbon steel.
Carbon steel not only has good plasticity, but also has exceptional physical and chemical properties such as high strength, good toughness, high temperature resistance, corrosion resistance, easy processing, impact resistance and ease of refining. These properties make carbon steel widely used.
Based on carbon content, carbon steel can be divided into low-carbon steel, medium-carbon steel and high-carbon steel.
As the carbon content increases, the hardness of carbon steel also increases, while its toughness decreases.
Steel is produced from pig iron by a steel mill through high-temperature calcination and other processes. The carbon and oxygen in the steel react to produce carbon dioxide, reducing the carbon content of the iron and turning it into steel.
To meet a wide range of needs and improve the performance of steel, alloying elements such as chromium, manganese and nickel are added to carbon steel during the casting process, resulting in what is known as alloy steel. These include chrome steel, manganese steel, chrome manganese steel and chrome nickel steel.
