In this article we will discuss about:- 1. Preparation of Wrought Iron 2. Properties of Wrought Iron 3. Uses.
Preparation of Wrought Iron:
It is prepared from pig iron by burning out C, Si, Mn, P and sulphur in a puddling furnace. So wrought iron is a purer form of pig iron. Pig iron contains 6% or more of these impurities but their percentage is reduced to about one per cent in wrought iron. Carbon content is reduced to about 0.02%.
In the process of purification of pig iron into wrought iron, a minute quantity of slag is incorporated into wrought iron and is uniformly distributed in it. The presence of slag gives fibrous structure to wrought iron.
Properties of Wrought Iron:
It can be readily worked and welded at temperature close to its melting point. It is ductile when cold and has good forming qualities. In resistance to corrosion, it is superior to mild steel. It has many practical applications owing to its ability to take on and hold protective metallic and paint coatings and its good machining and threading qualities. The mechanical properties of wrought iron are dependent upon the form of finished product.
Wrought iron does not contain impurities and is thus intensely soft. Due to very low carbon content its melting point is high and it cannot be used as casting alloy. Due to poor strength it has very little use. It cannot be heat treated for changing its physical properties.
Due to the presence of slag in wrought iron, it resists corrosion. It can be obtained in the form of plates, sheets, forged billets, structural shapes, bars, piping and tubing. The fibres tend to halt the crack slightly, rather than fracture outright if overloaded, and so give a warning of danger.
Uses of Wrought Iron:
1. It is used for pipe making due to its superior corrosion and fatigue resistance and better welding and threading qualities.
2. It is used for making bars for stay bolts, engine bolts and rivets etc. because properties demanded in these applications are corrosion and fatigue resistance.
3. For making plates.
4. For making special chains and crane hooks due to its good weldability and high impact strength.
5. It is also used extensively for general forging applications.