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What kind of defects will appear in cold drawing seamless precision steel pipe processing?

Author: Dagang precision tube time: January 11, 2019

 What kind of defects will appear in cold drawing seamless precision steel pipe processing?

   Cold drawn seamless precision steel pipe Processing defects:

1. Cold drawn seamless steel pipe will lead to the increase of micro defects such as lattice dislocation and surface roughness, and induce martensitic transformation and carbide precipitation. For example, the magnetic properties of austenitic steel increase after cold working.

2. The dislocation or phase transformation of material lattice occurs on the surface, which will become the initial position of pitting corrosion and other local corrosion. The phenomenon of cold drawing seamless precision steel pipe will have direct adverse effect when the deformation degree reaches 20% reduction of section ratio.

3. The residual stress will be left in the material after cold working of cold drawn seamless precision steel pipe, which is extremely unfavorable to the stress corrosion cracking resistance of the material. Any degree of cold working on cold drawn steel pipe will greatly increase the SCC sensitivity of cold drawn steel pipe material.

4. The cold working degree also has a bad effect on the high temperature rupture strength of cold drawn steel pipe. Generally, the higher the working temperature or the higher the fracture life requirement, the lower the allowable cold working degree.

Difference between cold drawn seamless precision steel pipe and ordinary seamless steel pipe:

1. The common seamless steel pipe is mainly characterized by no welding joint and can bear large pressure. The product can be very rough as cast or cold drawn.

2. Cold drawn seamless precision steel pipe is a product emerging in recent years, mainly because the inner hole and outer wall size have strict tolerance and roughness.

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