Effect of Solid Solution Treatment of Stainless Steel

 Effect of Solid Solution Treatment of Stainless Steel: The stainless steel is softened through the solid solution treatment. Generally heat the steel wire to about 950～1150℃ and keep the temperature for a period of time to fully and evenly dissolve carbide and various alloying elements in the austenite, and then rapidly quenching cool, the carbon and other alloying elements are too late to precipitate and obtain pure austenitic tissue.

There are three effects about the solid solution treatment. A. Enabling the steel wire tissue and components even and consistent is particularly important to the raw material, because various sections of hot-rolled rod’s rolling temperature and cooling speed are different which causes inconsistent tissue structure. Under high temperature, atomic activity increases, the σ phase dissolves, the chemical composition trends to be uniform and even single-phase tissue will be then obtained after rapid cooling. B. Eliminate the work hardening to facilitate the cold-working. Through the solid solution treatment, the contorted lattice recovers, the elongated and broken crystalline grain re-crystallizes, the internal stress is eliminated, the steel wire’s tensile strength decreases and the elongation rises. C. Recover the stainless steel’s inherent performance of corrosion resistance. 

Cold-working causing carbide precipitation and defective lattice enables the stainless steel’s performance of corrosion resistance decreased. The steel wire’s performance of corrosion resistance recovers to the best state after the solid solution treatment.

In terms of the stainless steel, the solid solution treatment’s three elements are temperature, time of heat preservation and cooling speed. The solid solution temperature is mainly determined by the chemical composition. Generally speaking, the solid solution temperature of the trademark with many varieties and high content of alloying elements should be correspondingly increased. Particularly, the steel with high content of manganese, molybdenum, nickel and silicon can achieve the softening effect only after increasing its solid solution temperature and making it full dissolved. However, for the stabilized steel, such as 1Cr18Ni9Ti, the carbide with stabilization elements is dissolved in the austenite when the solid solution temperature is high and it will precipitate from the grain boundary with the form of Cr23C6 in the following cooling causing inter-crystalline corrosion. To enable the carbides (TiC and NbC) of stabilization elements not to dissolve and not to solid dissolve, generally adopt the minimum solution temperature.