Ferrous Materials and Non-Ferrous Metals and Alloys 1 introduction

Partial annealing:

 It is a process where steel is heated slightly above lower critical

temperature and this annealing is applied for hypereutectoid steels only. It is also applied

to hypoeutectoid steels where hardness is to be reduced while improving machinability.

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Ferrous Materials and Non-Ferrous Metals and Alloys

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In this operation, pearlite is transformed to austenite and ferrite is partially deformed

into austenite. Heating and holding period is followed by slow cooling.

Isothermal Annealing:

 Steel is heated in the same way as it is treated in full annealing

and then it is rapidly cooled from 500°C to 100°C below critical temperature. This is

followed by keeping steel at this temperature for a long period which results in complete

decomposition of iron. Then this is cooled in air.

The isothermal annealing results in improved machinability and more homogenous

structure throughout the section.