For stainless steel seamless pipe, the three elements of the solution treatment temperature, holding time and cooling rate. Stainless steel seamless solution treatment effect is as follows:
1: Make stainless steel seamless organization and composition uniform, which is particularly important for the raw material, because hot-rolled pipes of each section rolling temperature and cooling rate are not the same, resulting in tissue structure is inconsistent. Exacerbated at high temperature atomic activities, σ phase dissolution, chemical composition tends to be uniform, after rapid cooling to obtain a homogeneous single phase.
2: Eliminate hardening, in order to facilitate continued cold. By solution treatment, recovery distorted lattice, elongated and broken grains recrystallization, to eliminate the internal stress, the wire tensile strength decreased, the elongation increased.
3: Restore the inherent corrosion resistance of stainless steel pipe. Because cold causes carbide precipitation, lattice defects, so that the corrosion resistance of stainless steel pipe fell. After solution treatment corrosion resistance of stainless steel seamless return to top form.
Solution temperature is mainly determined by the chemical composition. In general, many kinds of alloying elements, high content grades, the solution temperature should be increased accordingly. Especially manganese, molybdenum, nickel, silicon content of steel, only the solution temperature to fully dissolve, in order to achieve a softening effect. But stable steels, such as 321 stainless steel tube, the solution temperature is high carbide stabilizing elements fully dissolved in austenite, will Cr23C6 form in grain boundary precipitates in the subsequent cooling, causing intergranular corrosion. For the stabilizing element of carbide (TiC and NbC) does not break down, no solution, generally use the lower solution temperature.
Post time: Oct-18-2019