Important Heat Treatment Methods Are As Follows

1603 Words Oct 30th, 2016 7 Pages
Important heat treatment methods are as follows:
• Normalizing
• Annealing
• Hardening
• Tempering
NORMALIZING
As the name indicates, it is the method to bring the metal to its 'normal ' state. Thus the purpose is:
To produce uniform grain structure
To remove stresses produced during manufacturing processes like forging or cold working.
The process is to heat the steel 40 C above upper critical temperature for a sufficient time and then cooling it in still air. Low carbon steels are most often normalized.
ANNEALING
Annealing consists of a heating cycle, a holding period and a controlled cooling cycle. It is the method to soften the metal to make it machinable & increase ductility. It is also used for stress relieving & more effective than normalizing.
Low carbon steels (L.C.S) are heated up to 650 C & cooled in furnace or sand & is called process annealing.
Hypoeutectoid steels are heated 20-30 C above the upper critical temperature while hypereutectoid steels are heated to about 750 C for sufficient time & then slowly cooled in furnace and then in the air. It is called full annealing.
HARDENING
It is the method to make the steel sufficient hard to with stand wear and to enable the steel to cut.
The process is to heat hypoeutectoid steels up to 40 C above the U.C.T. (upper critical temp.) and hypereutectoid steels to 775 C. The steel is then 'Soaked ' & 'Quenched '. 'Soaking ' is the phenomenon to held the steel at required temperature for considerable time for…
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