INDUSTRY NEWS

 2017-08-16

The application of cold deformation may affect the properties of the aluminum profile on which the aluminum profile manufacturesshould have a lesson ahead. This article is going to talk about it on 3 aspects -- physical and chemical properties, mechanical properties, and structure and anisotropy, which helps you a basic understanding on effects of cold deformation. 

A: Physical and chemical properties.

1) Density.

After cold deformation, due to the micro-cracks or macroscopic cracks and other defects appeared in the inside of grain or between the grains, the density of aluminum profile decreases.

2) Resistance.

Intergranular material is damaged so that the grains directly contact with each other. The order of grain position, the intergranular and intraocular rupture, etc., all will have a significant impact on the resistance changes. The first two reduce the resistance with adding degree of deformation, while the latter is the opposite.

3) Chemical stability.

After cold deformation, the internal energy of aluminum profile can be increased, so that its chemical properties become more unstable and easy to be corrosion, especially prone to stress corrosion.

B: Mechanical properties.

After cold deformation of aluminum profile, due to the occurrence of intragranular and intergranular damage, the lattice distortion and the emergence of the second type of residual stress make a sharp decline in plasticity index, and in the limit state, it may be close to a completely brittle. What’s more, as the lattice distortion and the dislocation increase, the grain is elongated and refined, so the sub-structure appears. As a result, the strength index is greatly improved, that is, the phenomenon of processing hardening occurs.

C: Structure and anisotropy.

Aluminum profile after a large cold deformation happens to anisotropy due to the texture. For example, aluminum sheet in the deep drawing is prone to obvious earring. Reasonable control of processing conditions is needed to take full advantage of the beneficial aspects of texture and anisotropy, and to avoid or eliminate its negative aspects.