1. Precise steel pipes will cause external economic shortcomings such as dislocations in the lattice constant of the raw materials and increase in roughness, and cause austenite change and cementite dissolution. For example, after cold working, the martensitic steel exhibits a magnetic lifting condition.
2. Dislocations or changes in the lattice constant of the raw materials are generated on the surface, which will become the origin of partial erosion such as pitting. Conditions such as precision steel pipes have an immediate negative impact when the deformation level is reduced by 20%.
3. After the cold processing of precision steel pipes, internal stress will remain in the raw material, which is extremely bad for the stress corrosion cracking resistance of the raw material. Cold-drawn steel pipes at all levels of cold processing will increase the SCC sensitivity of cold-drawn steel pipe raw materials.
4. The level of cold working also has a negative impact on the high temperature and long-term compressive strength of cold drawn steel pipes. Generally, the higher the operating temperature of precision steel pipe or the higher the rupture service life, the lower the allowable cold working level.
The difference between precision steel pipe and general seamless steel pipe:
1. The main feature of general seamless steel pipes is that they have no electric welding seam, which can bear great working pressure. The product can be a very rough cast or cold drawn part.
2. Precision steel pipes are commodities that have appeared in recent years, mainly internal threads, surface specifications with strict dimensional tolerances and surface roughness.