What changes will the cold working process of steel pipes cause to the steel pipes

The cold working process is a common steel pipe processing method, which is often used to improve the strength, hardness, and wear resistance of steel pipes. The following changes will occur in steel pipes through cold working:

1. Deformation hardening: During the cold working process, the steel pipe will be plastically deformed by external forces, which will cause the shape and direction of the grains to change, the grain boundary slip will increase, and the dislocation-intensive area will be formed, making the steel pipe hard. This hardening is called deformation hardening, which improves the strength and hardness of the steel pipe.
2. Grain refinement: Cold working will cause the grains to be squeezed and deformed, and the grains will undergo recrystallization, the grain size will decrease, and the crystal interface will increase, thereby improving the strength and plasticity of the steel pipe.
3. Stress accumulation: During the cold working process, stress concentration and accumulation will occur inside the steel pipe, and these stresses may cause the steel pipe to deform or crack under subsequent stress.
4. Residual stress: During the cold working process, residual stress may be generated inside the steel pipe due to the non-uniform color of the steel pipe. These residual stresses may cause deformation or cracks in the subsequent processing or use, affecting the performance of the steel pipe.
5. Surface hardening: Cold working can sometimes also be used to improve the hardness and wear resistance of the steel pipe surface. For example, cold rolling, cold drawing, and other processes can form indentations and dislocations on the steel pipe surface, thereby improving the surface hardness and wear resistance.

In general, the cold working process will have a significant impact on the structure and performance of the steel pipe. By controlling the cold working parameters and process conditions, the performance of the steel pipe can be regulated and optimized.