The invention discloses a strengthening method of Nb-stabilized
austenitic stainless steel. The method comprises the following steps that S1, the Nb-stabilized
austenitic stainless steel is subjected to ultrahigh-temperature
decomposition treatment, and primary coarse MC
carbide in the material is completely redissolved; s2, cold rolling treatment is carried out, and
dislocation plugging is introduced into the material; s3, recrystallization
solution treatment is carried out, static recrystallization of the material is induced through deformation energy stored by
dislocation plugging, and coarsened grains in the material are refined again and recovered to an equiaxed
fine grain structure; and S4, synergistic
precipitation aging treatment is conducted, the recrystallized intracrystalline
substructure is evolved to form high-density faults, meanwhile, directional non-uniform
nucleation occurs on supersaturated solute atoms on the
fault plane, and synergistic formation and
precipitation of the faults and nanoscale secondary MC carbides are achieved. Compared with the prior art, the contradiction between dissolving the primary phase and maintaining the
fine grain structure is solved, and the material strength and
thermal stability are remarkably improved on the premise that the
plasticity of the material is not sacrificed.