Workshop Technology
During hot working of metals

Mechanical properties are improved due to refinement of grains
Grain structure of the metal is refined
Porosity of the metal is largely eliminated
All of the listed here

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Workshop Technology
Extrusion

Is extensively used for making bolts and nuts
Is used to improve fatigue resistance of the metal by setting up compressive stresses in its surface
Is used for reducing the diameter of round bars and tubes by rotating dies which open and close rapidly on the work
Consists of pressing the metal inside a chamber to force it out by high pressure through an orifice which is shaped to provide the desired form of the finished part

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