Normalizing Vs ANNEALING

Normalizing

Heating a metal above critical temperature upto 40 °to 50° C for both hypo and hyper eutectoid steels and keep it there for as per the time requirement .It is cooled by air in the room temperature

Aim of normalizing

• 1.      Soften metals
• 2.      Improve grain size
• 3.      Improve machinability
• 4.      Improve structure of weld
• 5.      refine grain structure
• 6.      Reduce residual stress

Metals prefer for normalizing

• 1.      Iron alloys (tool steel, carbon steel)
• 2.      Aluminium
• 3.      copper

ANNEALING

It is defined as process in which a metal is slightly above critical temperature  (30° to 50° C) for both hypo eutectoid and hyper eutectoid steels and keep it there as per time requirement . It is usually cooled inside the furnace while shutting it off

 Aim for annealing

• 1.      even grain structure production
• 2.      to improve formability of hard , brittle material so they don’t break while bending or pressing
• 3.      improve machinability
• 4.      remove residual stress

Metals prefer for annealing

• 1.      steels and cast iron
• 2.      aluminium
• 3.      copper

NORMALIZING	ANNEALING
1.After heat treatment it is cooled in room temperature	1. After heat treatment it is cooled in furnace while furnace is off
2. faster cooling rate	2. low cooling rate
3.less ductile and high hardness	3.more ductile and low hardness
4.cheap because cooling in room temperature	4. expensive because cooling require a furnace