Manufacturing of Wrought Iron

Wrought iron is converted from pig iron by a process called "puddling " in a reverberatory furnace. This is a low rectangular fire-brick chamber divided into two unequal parts by a wall which does not extend to the top of the furnace.

The larger portion is called the working chamber and the smaller one the fireplace. The fuel is bituminous coal with a long flame which passes over the wall and melts the iron and slag in the working chamber without bringing it in contact with the fuel. The mass is stirred around with a " rabble " until the carbon is eliminated and the pure iron floats as globules in the slag which has a lower melting point.

These globules are collected in balls, the slag is squeezed out, and they are ready for the finishing processes.

Wrought iron, which is the purest form of iron, is soft and has a fibrous structure. When heated it becomes plastic before it reaches the melting point, and may be rolled into thin sheets or rounds, and when cold worked into many other shapes.