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Wrought iron vs cast iron: A comparative analysis

Iron is one of the most alloyed elements on earth. It combines with various elements to form numerous materials. These materials all have different desirable properties. Iron is so versatile that its alloys can also combine with other elements to form thousands of new materials. Two well-known types of iron are wrought iron and cast iron. In this article, we will be analysing and comparing wrought iron vs cast iron. We shall discuss their distinct properties, advantages, disadvantages and applications.

Wrought iron

Wrought iron is an alloy of iron which contains very minute amounts of carbon (less than 0.08%). It is almost pure iron. It can also be described as iron that has been heated and worked upon with tools. The word “wrought” itself, is a past participle of work. Wrought iron is highly refined iron with small amounts of added slag.

Wrought iron properties

The properties of wrought iron are as follows:

Wrought iron and steel have a few similar properties. One of the reasons for this is their similarly low carbon content. People often ask questions like: can wrought iron rust? Or is wrought iron stronger than steel?

First of all, rust is the oxidation of iron. Wrought iron is 99% iron, therefore, it rusts. As for strength, the higher carbon content of steel make it stronger, harder, and less malleable than wrought iron.

Applications of wrought iron

With the advent of cheaper and better alternatives such as steel, wrought iron finds fewer applications in metallurgy. The following are some of its applications:

Cast iron

A chair made from cast iron

Cast iron refers to alloys of iron and carbon which contain carbon content of 2 – 4%. You can remelt, pour into a mould and allow this alloy to solidify. Hence the name, “cast” iron. Melting pig iron or smelting iron ore and mixing it with other alloys or scrap metal forms cast iron.

It might interest you to know that there are four types of cast iron which differ in their basic properties. What are the four types of cast iron? They are:

  1. White cast iron: This contains carbides which result in good wear resistance, high compression strength, and hardness.
  2. Grey cast iron: This contains graphite in its microstructure. It is easy to machine and is resistant to wear.
  3. Ductile cast iron: This is a form of grey iron which contains small amounts of caesium and magnesium. These elements nodulate the graphite in grey iron, thereby resulting in high strength and ductility.
  4. Malleable cast iron: When white cast iron undergoes heat treatment to improve its ductility, it forms malleable cast iron.

Cast iron properties

Cast iron generally has some distinct properties. These properties which are as a result of its mixed micro-structure are as follows:

Applications of cast iron

Now that we’ve discussed its properties, the next question is, what is cast iron used for? The following are some of the applications of cast iron:

Wrought iron vs cast iron: A comparative analysis

The following are some major differences between wrought iron and cast iron: