Iron+&+Steel

Cast iron: is a material made of iron with lots of carbon, it can be mold to any shape and in physical terms is strong in compression but weaker in tension, it breaks without warning.
===**Steel:** is a material made of iron with a touch of carbon. It is one of strongest materials used in construction. In physical terms the steel is strong in compression and tension but it losses strength in extremely temperatures. ===

**Corrugated Iron:**
Corrugated iron o GCI (Corrugated galvanised iron) is a building material composed of sheets of hot-dip galvanised mild steel cold-rolled to have a linear corrugated pattern in them.

This material is light, strong, corrosion-resistant, and easily transported, available everywhere and particularly lent itself to prefabricated structures and improvisation by semi-skilled workers.

CGI was invented in the 1840s. It was and still is widely used especially in rural and military buildings such as sheds and water tanks, like a cover for walls and roof. Particularly, in australia the corrugated iron is the most common roofing material and is even used in urban areas.

Post-reading activities:
• **What are the advantages of iron and steel over stone and brick?** In construction, the most important advantage is that the use of iron and steel provide structures with less expenditure of material, more stronger and taller.

• **What is the importance of steel and iron after the 20th. Century.?** Steel and iron have changed, in construction, the concept of the wall and the support; methods of their using (the welding and its capacity of distribute stresses between beams and columns) allows the most rigid and continuous structure style, as well it give to us new posibilities for coverings.

• **What are the characteristics of steel?** Steel is uniformly strong, elastic, and workable, and it´s resistent in all stresses (tension, compression and bending)

• **What are the disadvantages of steel and what solutions have been found?** Steel doesn´t support the corrosion, so have been created the alloys, such as stainless steel for exposed surfaces.

• **What is welding? What is its importance? Its characteristics.** Welding is the process of joining metals by melting the parts and then using a filler to form a joint. The welding allows continuous structures in which the joint is as firm as the member and which distributes stresses between beams and columns.

• **What shapes are formed with steel?** The commonest steel shapes are plates, angles, I beams, and U-shaped channels.

• **Are aluminum and stainless steel heavy metal alloys?** No, they are not. Aluminium and stainless steel are light metals who have come to favored for exterior construction because of their weather resistance.


 * Timeline of the evolution in the use of metals in history**