Role of Recovery and Recrystallization on the Post Cold Work Corrosion Performance in a Super Duplex Stainless Steel

Abstract

Cold rolled super duplex stainless steel (SDSS) were subjected to recovery (300 °C) and recrystallization (1020 °C) annealing. Annealing related microstructural changes were quantified with microtexture and phase-specific micro-hardness. Subsequent electrochemical characterization included potentiodynamic anodic polarization tests and Mott-Schottky analysis. It was established, for both single and two-phase specimens, that extensive recovery did not affect the electrochemical behavior, while the shortest recrystallization led to significant improvements in corrosion resistance. Improvements in corrosion performance of cold rolled SDSS was thus possible only through recrystallization, and associated removal of large lattice curvatures in the metallic substrate and reduced defect densities in the protective oxide film.

Effect of strain-induced martensite reverse transformation on microstructure evolution and electrochemical behaviour of 2304 lean duplex stainless steel

“…A more detailed examination in Figure 8 indicates that the recovery and recrystallisation phenomena occur early and more intensely in the ferrite regions (blue regions). According to Mondal et al [28] investigation extensive recovery at 300°C (30-1440 min) did not affect the electrochemical behaviour of cold-rolled super duplex stainless steel, although recrystallisation at 1020°C greatly improves the corrosion resistance. The significant increase in pitting potential at the specimens annealed from 700°C to 800°C can be associated with the reversed austenite and the reduced defect density with increasing temperature (Figure 8).…”