Outline of processing related to the microstructure of steels
The microstructure of steel can be affected by different heating, cooling and processing methods.
If this is carefully controlled, the properties such as hardness, ductility and tensile strength can be predetermined to fulfil a variety of uses. The different alloys present in a metal can be identified under a microscope and this method can be used to analyse failures etc. during manufacture. The metal is finally shaped under temperature controlled conditions which can alter its characteristics and strength.
The properties of steel can be altered by heating and cooling.
The most dramatic transformations can be achieved in steel by fast cooling or quenching. This occurs when hot steel is immersed in oil. Instead of the normal crystal structure, small needle-shaped crystals of martensite form creating a great deal of internal stress within the metal. This makes the metal extremely hard but also brittle.
Metal components which are subjected to quenching are hard. Typical examples are tools or fixings.
