1) Flattening with a hammer 
The stretching of metal by hammering or rolling the surface.
A technique of blasting the surface of metal with shot. Improves appearance and hardens the surface.
Mechanical working of metal by hammer blows or shot impingement.
The mechanical working of metals by means of hammer blows. Peening tends to stretch the surface of the cold metal, thereby relieving contraction stresses.
A stream of sharp material particles which break superficial fibres, reducing internal stress fields.
Mechanical working of metal by hammer blows or shot impingement.