The most important metal for the development of any country is steel. People have great confusion between steel and iron, basically steel is an alloy of iron and carbon while iron is just a element. The most common form of iron that is produced in steel plants is pig iron. There are various other forms of iron like cast iron, sponge iron etc . Today, steel is one of the most common materials in the world, with more than 1.3 billion tons produced annually. It is a major component in buildings, tools, ships, automobiles, machines and weapons. Now let us see the brief difference between steel and iron .

Iron vs steel
rusted iron and pipes of stainless steel

Iron and steel
  1. Iron that contains more than 2% of carbon as constituent is termed as cast iron.If the constituent of carbon is less than 2% it can form steel.Steel is basically produced by pig iron by reducing the concentration of carbon from it and removing other impurities (sulphur, phosphorus etc) in furnace (Electric arc, Open Hearth etc).
  1. Pig iron is made from raw iron (iron ore) and coke which is charged in blast furnace . Steel is generally produced by pig iron but it is sometimes also produced by sponge iron. Steel is made  in LD converter by oxygen blowing  in which molten pig iron is used as charging material, Electric Arc furnace is also used to produce steel in which Scrap steel or DRI iron is heated to  temperature of about 1700oC by electrical energy for about 40-50 min generally.
    The area where steel is produced in plant is called Steel Melting Shop.
  1. Iron is comparatively more ductile and weak as compared to Steel .Steel has high tensile strength than iron and its properties can be altered by addition of alloying elements (nickel , magnesium, chromium and vanadium).
  1. The most important property is Steel don’t get rusted easily as compared to iron . Stainless steel is generally used as rust free steel.
  1. Iron was discovered earlier around in 4000BC (according to archeological department) .Steel was discovered much later . The modern  steelmaking began with the introduction of Henry Bessemer’s Bessemer process in 1855.

Sr No. Iron Steel
Components Iron is an element that is found as iron ore in earth .The most common form of iron produced is pig iron . Other  forms are white cast iron, grey cast iron, sponge iron etc. Steel is a alloy of  iron and carbon  and is the most commonly used metal worldwide. Other forms stainless steel .
Constituents Main Constituents  of pig Iron are Fe and  carbon more than 2% maximum 6.67%. Carbon content  0.02 to 2% , other alloying elements are added.
Production Process It is made from iron ore and coke in blast furnace at temperature of about 1500 °C- 1600 °C It is made from pig iron or sponge iron in LD converter at temperature of about 1700 °C
Strength Iron is comparatively weak as compared to steel  and is more rust prone. Steel is Rust free and has greater tensile strength. Properties can be changed by adding alloying elements
History Iron was discovered first in about 4000BC in Egypt. Before that bronze was common metal known . In other parts of world it was founded later because it requires very high temperature for production Technique for making steel was discovered during ancient period but Henry Bessemer is most commonly known for modern steel making.
Process Environment Production of iron (pig iron) requires reducing environment in the furnace . Production of  Steel requires Oxidizing environment inside the furnace.

 

 

Process of making iron and steel

 

 

Process of Iron Making

PIG IRON is the molten iron made from blast furnace,In which iron ore, coke,and sinter . Charcoal and anthracite have also been used as pulverized fuel. Coke works as reducing agent as well as fuel for molten iron making.

As mentioned above Pig iron has a high carbon content, typically 3.5–4.5%  along with silica and other constituents of dross, due to which it is brittle and is not used directly for commercial purpose.

It is produced in the form of INGOTS from the blast furnace.

The blast furnace gas that is produced during the process is a mixture of carbon dioxide, carbon monoxide, hydrogen and nitrogen and has a calorific value between 3,200 and 4,000 kJ/m³ so it can be used for other heating purposes.

 

ladle pouring molten steel into other ladle
steel melting shop

 

Process of Making Steel
 As it is discussed earlier steelmaking is the process of producing steel from iron ore and scrap(iron or steel ). In this process, impurities such as  silicon, nitrogen, phosphorus, sulfur and excess carbon present in pig iron or raw iron are removed and alloying elements such as manganese, nickel, chromium and vanadium are added to produce different grades of steel. Now a days there are basically two major commercial processes used for making steel, first is basic oxygen steelmaking, which uses molten pig iron produced from the blast furnace and scrap steel as raw material to produce steel. Second is electric arc furnace (EAF) steelmaking, which uses scrap steel or direct reduced iron (DRI) (also known as SPONGE IRON) as the main feed to produce steel . In Oxygen steelmaking,  the exothermic nature of the reactions inside the vessel serve as main fuel,  where as in EAF steelmaking, solid scrap or DRI is melted by electrical energy.SPONGE IRON) as the main feed to produce steel . In Oxygen steelmaking,  the exothermic nature of the reactions inside the vessel serve as main fuel,  where as in EAF steelmaking, solid scrap or DRI is melted by electrical energy.

 

workman inspecting tuyers of blast furnace
Blast Furnace

 

I hope this article will let you know the difference between the terms STEEL and IRON , and for any other query feel free to contact us through mail or social networking site .

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