In order to improve the performance of stainless steel, often need to adopt a certain way of cold work, such as cold drawing, cold rolling, cold rolling, cold, cold, cold bending distortion and so on, but the effect will be to arrive at the same time can also cause certain damage, all of these cold actually like welding, would give the performance of the stainless steel tube, especially corrosion resistant brings the inevitable damage or heat resistant performance. Concrete is:
1, will lead to material lattice dislocation and other microscopic defects and surface roughness increase, and induce martensitic transformation and carbide precipitation. For example, after cold processing, austenitic steel shows an increase in magnetism.
2, resulting in material lattice dislocation or phase transformation occurs on the surface, will become the initial location of local corrosion such as pitting. This phenomenon will have direct adverse effects when the deformation degree reaches 20% reduction of section rate.
3, after cold processing, residual stress will be left in the material, residual stress on the resistance to stress corrosion cracking (SCC) of the material is very adverse. Any degree of cold processing will greatly increase the SCC sensitivity of the material.
4, the degree of cold processing on the high temperature endurance strength of austenitic stainless steel also has a bad effect. Generally, the higher the operating temperature or the higher the fracture life requirements, the lower the allowable degree of cold processing.
5, for the application of stainless steel pipe under alternating load, cold processing will cause adverse effects by reducing the elongation and residual elongation so that the cracking expansion rate increases.