Kinetics of Cr 2 N Precipitation and Its Effect on Pitting Corrosion of Nickel-Free High-Nitrogen Austenitic Stainless S
- PDF / 2,760,526 Bytes
- 9 Pages / 593.972 x 792 pts Page_size
- 9 Downloads / 234 Views
JMEPEG https://doi.org/10.1007/s11665-020-05098-w
Kinetics of Cr2N Precipitation and Its Effect on Pitting Corrosion of Nickel-Free High-Nitrogen Austenitic Stainless Steel K. Krishna Kumar, J. Anburaj, R. Dhanasekar, T. Satishkumar, J. Abuthakir, P. Manikandan, and R. Subramanian (Submitted May 17, 2020; in revised form July 14, 2020) In the present work, hot-rolled nickel-free high-nitrogen austenitic stainless steels (HNSS) were solution annealed and aged at 700, 800 and 900 °C for 14 h. Precipitation behavior of Cr2N at the grain boundaries (GB) of HNSS was studied using TC-PRISMA simulation and TEM analysis. Pitting corrosion behavior of HNSS at solution annealed and aged conditions were studied using cyclic polarization and electrochemical impedance spectroscopy (EIS) analysis. TC-PRISMA simulation results showed that equal volume fraction of chromium nitride (Cr2N) precipitates was observed in GBs of austenite in all three aging conditions. However, large size precipitates were observed in samples aged at 900 °C compared to samples aged at 700 and 800 °C. TEM investigations showed the presence of discrete needle like Cr2N precipitates at the GBs and coarse lamellar austenite in regions adjoining the GBs in samples aged at 700 °C aging temperature. Disk-type Cr2N precipitates were observed in GBs of austenite in 900 °C aging temperature. Besides, sample aged at 900 °C exhibited relatively higher repassivation behavior compared to solution annealed and samples aged at 700 and 800 °C. Keywords
chromium nitride, cyclic polarization, electrochemical impedance spectroscopy, high-nitrogen austenitic stainless steels, pitting corrosion, TC-PRISMA, TEM
1. Introduction Nickel-free high-nitrogen austenitic stainless steels are a group of non-magnetic and high-strength steels used in medical and oil field applications. These steels exhibit high resistance to pitting corrosion along with high strength and toughness. Though Ni addition enhances engineering properties in stainless steels, it is allergic to human and animals bodies (Ref 1-3). Usage of nickel not only increases the cost but also leads to environmental hazard due to increased energy consumption during stainless steel melting (Ref 3). To counteract these effects, development of low nickel and nickel-free ASS has been carried out by many researchers (Ref 4-15). Manganese and nitrogen are commonly used as substitutes for nickel in austenitic stainless steels. Increase in manganese in austenitic stainless steels causes a significant reduction in general and localized corrosion resistance (Ref 11). However, nitrogen addition counteracts the effect of manganese on corrosion resistance in austenitic stainless steels. Few reports (Ref 12, 13) have reviewed the harmful effects of nitrogen in
K. Krishna Kumar, J. Anburaj, R. Dhanasekar, J. Abuthakir, P. Manikandan, and R. Subramanian, Department of Metallurgical Engineering, PSG College of Technology, Coimbatore, Tamilnadu 641 004, India; and T. Satishkumar, Department of Mechanical Engineering, Amrita School of Engi
Data Loading...
