Effect of Annealing Temperature on the Mechanical and Corrosion Behavior of a Newly Developed Novel Lean Duplex Stainless Steel

Abstract

Abstract:The effect of annealing temperature (1000-1150 °C) on the microstructure evolution, mechanical properties, and pitting corrosion behavior of a newly developed novel lean duplex stainless steel with 20.53Cr-3.45Mn-2.08Ni-0.17N-0.31Mo was studied by means of optical metallographic microscopy (OMM), scanning electron microscopy (SEM), magnetic force microscopy (MFM), scanning Kelvin probe force microscopy (SKPFM), energy dispersive X-ray spectroscopy (EDS), uniaxial tensile tests (UTT), and potentiostatic critical pitting temperature (CPT). The results showed that tensile and yield strength, as well as the pitting corrosion resistance, could be degraded with annealing temperature increasing from 1000 up to 1150 °C. Meanwhile, the elongation at break reached the maximum of 52.7% after annealing at 1050 °C due to the effect of martensite transformation induced plasticity (TRIP). The localized pitting attack preferentially occurred at ferrite phase, indicating that the ferrite phase had inferior pitting corrosion resistance as compared to the austenite phase. With increasing annealing temperature, the pitting resistance equivalent number (PREN) of ferrite phase dropped, while that of the austenite phase rose. Additionally, it was found that ferrite possessed a lower Volta potential OPEN ACCESSMaterials 2014, 7 6605 than austenite phase. Moreover, the Volta potential difference between ferrite and austenite increased with the annealing temperature, which was well consistent with the difference of PREN.

Atmospheric-Induced Stress Corrosion Cracking of Grade 2205 Duplex Stainless Steel—Effects of 475 °C Embrittlement and Process Orientation

“…This can possibly be attributed to the formation of deformation-induced martensite, which is typically indexed as ferrite due to its similar crystallographic structure. Deformation-induced martensite in 2205 DSS has been reported after plastic deformation by cold rolling (ε = 3.38), which supports this assumption [40][41][42].…”

Effects of Heat Input on Microstructure, Corrosion and Mechanical Characteristics of Welded Austenitic and Duplex Stainless Steels: A Review

“…Nitrogen, an austenite stabilizer, is added as both a solid-solution hardener and resistance promoter against pitting corrosion in chloride-containing media. As previously reported, chromium nitrides precipitate in the ferritic phase when a DSS is quenched from a very high annealing temperature [76][77][78]. Chromium nitrides precipitated when rapid cooling occurred in weld metal or the HAZ of welded DSS [78][79][80][81].…”

“…However, their corrosion possibilities are relatively uneven: joint B < joint A < 2205 DSS. The corrosion possibility is a constant index of electrochemical corrosion renitency and exhibits the sensitivity to corrosion of the material [77,91,104]. Table 3.…”

SKPFM measured Volta potential correlated with strain localisation in microstructure to understand corrosion susceptibility of cold-rolled grade 2205 duplex stainless steel

“…Local initiation sites of pitting corrosion in austenite were primarily located in the grain interior, possibly related to regions containing local plastic strains. Alternatively, some of these discrete sites may also be associated with strain-induced martensite, which has been reported for duplex stainless steels [49,50].…”