The discovery and use of metals has been the most important achievement in human history. Metals are the principal raw material for production of tools and engineering equipment and their discovery contributed enormously to advancements in human civilization.
A part from gold and silver, which were more or less ornamental. Tin, copper, lead and iron were the first industrial materials to be discovered and used extensively. Written evidences in Persian Literature indicate that thousands of years ago people in this country were able to extract pure metals from minerals, melt the metals and produce castings, deform metals, mix metals together and produce alloys. They were also familiar with heat treatment of steel, coating of metals with gold and silver tin, Welding and brazing techniques.
