Iron

 Iron rusts, or corrodes in air because it dissolves in the acid solution provided by the moisture and the carbon dioxide of the air to form hydrous oxide. In an atmosphere which is rich in sulphur compounds, the process will be repaid.

                                              Our industrial system is largely based on the use of iron and its alloys. It is the world’s most important metal, but rarely found in a pure state. Iron ore has to be smelted to separate the metal from other elements. The molten iron, which flows from the blast furnace after smelting is pig iron. This contains many impurities but it is a raw material for cast iron and wrought iron.

   Cast iron is made from pig iron by resmelting it with in a blast furnace. The coke raises the temperature and helps remove the impurities. the molten cast iron is tapped from the base of the furnace and poured into moulds. Although it is brittle, cast iron metals and moulds because it does not distort when red hot and corrodes only slightly in water. Cast iron is used for stoves, fireplaces, manhole covers, water pipes and rain gutters. If cast iron is resmelted the result is wrought iron. It is almost pure form of iron. It can be easily shaped or wrought until the 1870s was used for bright-building and engineering. Now-a-day it is used mainly for decorative purpose. it gave way to master metal steel which was first mass-produced in the 1870s and which combines the easy- to- handle qualities of wrought iron with the toughness of cast iron.

Source: collected from few books.

By
Rushalli