Workshop Technology
Piercing is an operation of cutting

A flat sheet to the desired shape
A hole (other than cylindrical) in a sheet of metal by the punch and the die
A number of holes evenly spaced in a regular pattern on a sheet of metal
A cylindrical hole in a sheet of metal by the punch and the die

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Workshop Technology
During hot working of metals

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

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