The difference is percentage of carbon, the main alloy element. Those irons containing less than 2%
carbon are known as steels while those containing more than 2% carbon are known as pig iron. Pig iron
is obtained from iron ore by processing it with coke in a blast furnace. This pig iron is then further
processed to reduce the carbon content in different furnaces to obtain steels. These steels can be then
further processed to obtain alloy steels, stainless steels by adding elements such as silicon, manganese,
chromium, nickel, etc.
iron is an element: a pure substance. It rusts ( forms iron oxide) on exposure to water and air. One of its
physical properties is that is quite brittle for a metal. Steel of a mixture of two elements iron and carbon,
with more useful properties than pure iron for many industrial purposes.
There are many differences between iron and steel. Primarily, iron is an element while steel is an
alloy comprising of iron and carbon. However, in this alloy iron is present in a greater quantity.
You can add various other metals to steel so as to produce alloys that have different properties.
For example, if chromium is added to steel, stainless steel is the product. It is durable and doesn’t
rust easily. In the construction industry steel is used on a large scale. This is because steel is
stronger than iron and it has better tension and compression properties.
Another difference can be perceived via looking at the percentage of carbon. The iron that
contains less than 2% of carbon is called steel whereas which contain more than 2% of carbon is
known as pig iron. When iron ore is processed with coke in a blast furnace, pig iron is obtained.
When this pig iron is further processed to reduce the carbon percentage, in various furnaces, steel
is obtained. Now, steel can be further processed to obtain various types of alloys. Elements like
silicon, manganese and chromium are added for making alloys.
Looking back at the history, it is not exactly known when iron making technique was actually
discovered. However, according to certain archaeological findings, iron was used in making
tools in Egypt in 3000 BC. The Greeks advanced a little further and in 1000 BC, they
manufactured hardened iron weapons. Thus all other type of iron that was manufactured can be
classified under the category of wrought iron until 1400 AD. It was only after 14th century,
furnaces that were used in the smelting process increased in sizes. The iron was pushed in the
upper part of these furnaces. It was reduced to metallic iron and then carbon rich gases were
introduced by a blast, so that metallic iron would absorb them. The end product thus obtained
was pig iron. It was further refined to make steel.
1. Iron is an element while steel is an alloy.
2. Iron was known to the humans from the beginning of civilization; however steel was
discovered much later.
3. Steel is a derivative of iron.