Cold rolled steel – is manufactured from hot rolled coil that has been chemically cleaned before being rolled. The coil is initially cold, however while being reduced, the coil will get hotter as the steel work hardens. The cold rolling reduces the thickness of the steel and at the same time changes the mechanical properties of the steel. Cold rolled steel must be further processed,as the steel react with water in the air and form rust. In most cases, it is covered with a thin layer of oil prevent oxygen reacting with surface. Cold rolled steel is available in a range of grades, each with a range of properties for differing applications.