Engineering Materials
Ductile cast iron

Is also known as chilled cast iron and is obtained by cooling rapidly. It is almost unmachinable
Contains 1.7 to 3.5% carbon in Free State and is obtained by the slow cooling of molten cast iron
Is produced by small additions of magnesium (or creium) in the ladle. Graphite is in nodular or spheroidal form and is well dispersed throughout the material
Is produced by annealing process. It is soft, tough and easily machined metal

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Engineering Materials
Recrystallization temperature is one

At which new spherical crystals first begin to form from the old deformed one when a strained metal is heated
At which change of allotropic form takes place
At which crystals first start forming from molten metal when it is cooled
At which crystals grow bigger in size

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Engineering Materials
The temperature required for full annealing in hypereutectoid steel is

30° C to 50° C above upper critical temperature
30° C to 50° C above lower critical temperature
30° C to 50° C below upper critical temperature
30° C to 50° C below lower critical temperature

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