forced air, oil, brine solution
Normalizing
Purpose of normalizing steel is to
To produce fine grain size in the metal.
- To remove stresses and strains formed in the internal structure due to repeated heating and uneven cooling
- hammering.
- To reduce ductility.
- To prevent warping.
Martensite
If the hot steel is cooled rapidly the austenite changes into a new structure called ‘MARTENSITE’. This structure is very fine grained, very hard and magnetic. It is extremely wear-resistant and can cut other metals.
Annealing
The annealing process is carried out by heating the steel above the critical range, soaking it for sufficient time to allow the necessary changes to occur, and cooling at a predetermined rate, usually very slowly, within the furnace.
To improve machinability
Purpose of Annealing process is to
- To soften the steel.
- To improve the machinability.
- To increase the ductility.
- To relieve the internal stresses.
- To refine the grain size and to prepare the steel for subsequent heat treatment process.