Austenitic stainless steel is softened by solid solution treatment. Generally, the stainless steel pipe is heated to about 950～1150℃, kept for a period of time, so that carbides and various alloying elements are fully and uniformly dissolved in the austenite, and then quenched quickly. , Carbon and other alloying elements are too late to separate and obtain pure austenite structure, which is called solution treatment.

The effect of solution treatment has three points:

  1. Make the structure and composition of the steel pipe uniform.

     Which is particularly important for the material. Because the rolling temperature and cooling rate of each section of the hot-rolled wire rod are different, the structure of the structure is not the same.At high temperatures, the atomic activity intensifies, the σ phase dissolves, the chemical composition tends to be uniform, and a uniform single-phase structure is obtained after rapid cooling

2. Eliminate work hardening to facilitate continued cold working.

 Through solution treatment, the distorted crystal lattice is recovered, the elongated and broken crystal grains are recrystallized, the internal stress is eliminated, the tensile strength of the steel pipe decreases, and the elongation rate increases.

3. The inherent corrosion resistance of rehabilitation stainless steel.

 Due to the separation of carbides formed by cold working, the defects of the crystal lattice reduce the corrosion resistance of stainless steel. After solution treatment, the corrosion resistance of the steel pipe is restored to the best condition.

Regarding stainless steel pipes, the three elements of solution treatment are temperature, heat preservation time and cooling rate. The solid solution temperature is mainly determined based on the chemical composition.

Generally speaking, for trademarks with a large variety of alloying elements and high content, the solution temperature should increase accordingly. Especially for steels with high manganese, molybdenum, nickel, and silicon content, the softening effect can only be achieved by advancing the solid solution temperature to make it fully dissolved.