Abstract: Effects of single-pass cold rolling with large deformation and annealing treatment on microstructure and properties of the 2205 duplex stainless steel were studied by means of microscopic observation, X-ray diffraction, Vickers microhardness and potentiodynamic polarization curve measurement. The results show that due to the single-pass cold rolling with large deformation, severely elongated grains are significantly broken to form fibrous microstructure and high-density dislocations pile-up, which significantly increases the hardness of the tested material by about 1.5 times, and the self-corrosion current density is 2% lower than that of the original specimen due to the grain refinement, the corrosion resistance of which in 3.5%NaCl solution is slightly improved. The cold-rolled specimen annealed at 500 ℃ for 4 h can refine the microstructure to about 300 nm, the corrosion resistance of which can significantly improve, and the self-corrosion current density reduces by 33% compared with original specimen. When the annealing temperature is increased to 700 ℃, the degree of dislocation annihilation in the two-phase microstructure is not uniform, the σ phase will precipitate at the phase boundary, and the hardness will be further increased, but it is not good for the corrosion resistance, and the self-corrosion current density decreases by 3% compared with original specimen.

Key words: 2205 duplex stainless steel, deformation annealing, hardness, corrosion resistance