Effect of thermal aging on corrosion behavior of duplex stainless steels

• Published in: SN applied sciences 2022-04, Vol.4 (4), p.97-18, Article 97
• Main Authors: Murkute, Pratik, Oware Sarfo, Kofi, McGieson, Isak, Santala, Melissa K., Zhang, Yongfeng, Árnadóttir, Liney, Tucker, Julie D., Isgor, O. Burkan
• Format: Article
• Language: English
• Subjects: Aging; Aging (metallurgy); Alloys; Applied and Technical Physics; Boron; Chemistry; Chemistry/Food Science; Corrosion; Corrosion currents; Corrosion effects; Corrosion rate; Corrosion resistance; Corrosion resistant alloys; Corrosion resistant steels; Dissolved oxygen; Duplex stainless steels; Earth Sciences; Electrochemical analysis; Electrochemical characterization; Electrochemistry; Electrolytes; Engineering; Environment; High temperature; Investigations; Materials Science; Mechanical properties; Metallurgy; Nuclear power plants; Pitting (corrosion); Pressurized water reactors; Research Article; Scanning electron microscopy; Stainless steel; Steel alloys; Temperature; Thermal aging; Thermal resistance
• ISSN: 2523-3963; 2523-3971
• DOI: 10.1007/s42452-022-04978-1

Despite their exceptional mechanical and corrosion properties, duplex stainless steels (DSS) have not found widespread use in high-temperature applications due to concerns over thermal aging and embrittlement at elevated operational temperatures (> 300 °C). The present study investigated the effect of thermal aging time on the electrochemical properties of lean and standard grade DSS that are exposed to a range of pressurized water reactors containing LiOH and H 3 BO 3 . The results indicated that the electrolyte chemistry plays a significant role in the corrosion behavior of the DSS alloys. Corrosion resistance decreased with thermal aging time for all DSS alloys; however, standard grade DSS (2205 and 2209-w) alloys showed better corrosion resistance than lean grades (2003, 2101, 2101-w). The presence of dissolved oxygen in the electrolytes resulted in a significant increase in corrosion rate for the DSS alloys, but it did not affect the general trend of corrosion rates with aging time. All DSS alloys became vulnerable to pitting corrosion due to chloride addition, but the pitting resistance decreased with increasing thermal aging time. Increased boron B content resulted in degradation of corrosion resistance of the DSS alloys, while minor changes in pH did not show a significant change in corrosion resistance. Mechanical and metallurgical characterization coupled with electrochemical characterization of the DSS alloys gave a comprehensive insight into the effects of thermal aging on the electrochemical response of the DSS. Graphical abstract Article highlights Effect of thermal aging on corrosion behavior of five DSS in PWR water chemistries are studied. Standard grade DSS show higher corrosion resistance than lean grade DSS after thermal aging. Corrosion current density increases with increasing thermal aging time. Increasing boron content increases the corrosion rates of DSS alloys Chlorides makes all alloys vulnerable to pitting at all aging times.