The plastic deformation of metal at room temperature has great influence on the structure and properties of metal, such as working hardening, internal stress and anisotropy. 

Plastic deformation of work hardening causes dislocation proliferation, dislocation density increase, dislocation delivery occurs in different directions, and dislocation movement is hindered, resulting in metal work hardening.Work hardening can improve the hardness, strength and deformation resistance of the metal, and reduce the plasticity, making it difficult to deform in the cold state. 

The distribution of internal stress plastic deformation in the metal body is not uniform, so after the removal of external force, the elastic recovery of all parts will not be exactly the same, which makes the metal body among all parts of the mutual balance of internal stress, namely residual stress.The residual stress reduces the dimensional stability of parts and increases the tendency of stress corrosion. 

After the cold plastic deformation of the anisotropic metal, the slip zone or twin zone appeared inside the grain.The grains also elongate and distort along the deformation direction.When the deformation is large (such as 70% or more) and in one direction, the orientation of the atoms in the grain tends to be the same, and the inclusions in the metal are elongated along the deformation direction to form fibrous tissue, causing the anisotropy of the metal.The strength, plasticity and toughness along the deformation direction are higher than that along the transverse direction.When the metal is deformed in the hot state, due to recrystallization, the orientation of the grain will deviate from the deformation direction to different degrees, but the direction of the fiber formed by the elongated inclusion remains unchanged, so the metal still has anisotropy.