Effect of precipitates on mechanical properties for annealed Fe-19Cr-2Mo-Nb-Ti ferritic stainless steel

摘要

Mechanical properties of Fe-19Cr-2Mo-Nb-Ti ferritic stainless steel were investigated after annealing from 850 °C to 1050 °C. With increasing annealing temperatures, the low-angle grain boundaries are evolved into high-angle grain boundaries, while the finer Laves phases are changed into coarsened (Nb,Ti)(C,N) precipitate, weakening the pinning grain boundaries effect of precipitates on inhibiting the grain growth. Accordingly, the amount of Nb in solution can increase from dissolution and coarsening of Laves phases, deteriorating the solid solution strengthening effects of Nb in the matrix, and then the values of tensile strength decrease from 829 MPa to 478 MPa.