Metals are usually divided into groups:
It is important that you know the difference between the two.
Ferrous means that the metal contains IRON and is MAGNETIC. Examples are:
High Carbon Steel
Non Ferrous means that the metal does NOT contain IRON. Examples are:
Metals are then divided again into:
Again it is important to know the difference and be able to give examples of the different types and some uses of these metals.
Alloys are mixtures of other metals (think of it like a cake which is made of different ingredients). By mixing different metals together a new material is formed with different properties and different working characteristics.
Brass is an Alloy it is made from copper and zinc.
The properities of metals can be changed using heat or by working them.
Heat can be used to significantly change the way in which a metal will perform or work.
Annealing is a process where the metal is gently heated and then left to cool, this has the effect of making the metal ‘softer’
Hardening is a process where the metal is heated up and then rapidly cooled. Each metal has a specific upper temperature which it must reach if hardening is to take place. This temperature is determined by the state of the atoms in the metal. At the specific heat they rearrange themselves and thus change the structure of the metal and therefore it properties. This dramatic process often makes metals brittle which is not very useful so the metal then has to be tempered as well.
Tempering makes the metal tougher and less likely to break when it is being use or when it is being processed.
The tempering process can be seen happening as this changes the colour of the metal (heat is applied in a very controlled fashion).