Annealing
Hardening
Tempering
Normalising
To add cutting ability
To relive strain and stress
To refine the grain structure
To regulate the hardness and toughness
To increase wear resistance
To relieve the internal stress
To refine the grain structure of the steel
To transmit torque
Assembly purpose
Lock the assembly part
Permit clearance between mating part
1:19
1:20
1:50
1:100