Physics:Ferrous Metals
Today， iron is the backbone of the world we've built. It is strong， plentiful， and cheap. Iron comes from iron ore such as haematite， which is similar to rust. It is a combination of iron and oxygen. Iron and carbon are known as steel. The carbon content affects the properties. We have pure iron， low carbon steel， medium carbon steel， high carbon steel and cast iron. The low carbon is soft and easily scratched. The high carbon is much harder.
- Added：2006
- Country：Australia
- Duration：24
- Time of update：2011/8/16 14:39:24