1. Make the structure and composition of the steel pipe uniform, which is especially important for the raw materials, because the rolling temperature and cooling rate of each section of the hot-rolled wire are different, resulting in an inconsistent organizational structure.
At high temperatures, atomic activity increases, the σ phase dissolves, and the chemical composition tends to be uniform. After rapid cooling, a uniform single-phase structure is obtained.
2. Eliminate work hardening to facilitate continued cold working.
Through solution treatment, the distorted lattice is restored, the elongated and broken grains are recrystallized, the internal stress is eliminated, the tensile strength of the steel pipe is decreased, and the elongation is increased.
3. Restore the inherent corrosion resistance of stainless steel.
The precipitation of carbides and lattice defects due to cold working reduce the corrosion resistance of stainless steel. After solution treatment, the corrosion resistance of the steel pipe is restored to the best state.